+----------------------+-----------------------------------------------+
| *                    | **Evaluation of Lightweight Material**        |
| *DOT/FAA/AR-96/110** |                                               |
|                      | **Concepts for Aircraft Turbine**             |
| Office of Aviation   |                                               |
| Research             | **Engine Rotor Failure Protection**           |
|                      |                                               |
| Washington, D.C.     | July 1997                                     |
| 20591                |                                               |
|                      | Final Report                                  |
|                      |                                               |
|                      | This document is available to the U.S. public |
|                      |                                               |
|                      | through the National Technical Information    |
|                      |                                               |
|                      | Service, Springfield, Virginia 22161.         |
|                      |                                               |
|                      | ![](me                                        |
|                      | dia/image1.emf){width="0.34305555555555556in" |
|                      | height="0.3548611111111111in"}                |
|                      |                                               |
|                      | U.S. Department of Transportation             |
|                      |                                               |
|                      | **Federal Aviation Administration**           |
+----------------------+-----------------------------------------------+

**NOTICE**

> This document is disseminated under the sponsorship of the U.S.
> Department of Transportation in the interest of information exchange.
> The United States Government assumes no liability for the contents or
> use thereof. The United States Government does not endorse products or
> manufacturers. Trade or manufacturer\'s names appear herein solely
> because they are considered essential to the objective of this report.

**Technical Report Documentation Page**

+-----------------------+---+---------+-----------+---+--------+----------+
| **1. Report No.**     | * |         |           | * |        |          |
|                       | * |         |           | * |        |          |
| > DOT/FAA/AR-96/110   | 2 |         |           | 3 |        |          |
|                       | . |         |           | . |        |          |
|                       | G |         |           | R |        |          |
|                       | o |         |           | e |        |          |
|                       | v |         |           | c |        |          |
|                       | e |         |           | i |        |          |
|                       | r |         |           | p |        |          |
|                       | n |         |           | i |        |          |
|                       | m |         |           | e |        |          |
|                       | e |         |           | n |        |          |
|                       | n |         |           | t |        |          |
|                       | t |         |           | \ |        |          |
|                       | A |         |           | ' |        |          |
|                       | c |         |           | s |        |          |
|                       | c |         |           | C |        |          |
|                       | e |         |           | a |        |          |
|                       | s |         |           | t |        |          |
|                       | s |         |           | a |        |          |
|                       | i |         |           | l |        |          |
|                       | o |         |           | o |        |          |
|                       | n |         |           | g |        |          |
|                       | N |         |           | N |        |          |
|                       | o |         |           | o |        |          |
|                       | . |         |           | . |        |          |
|                       | * |         |           | * |        |          |
|                       | * |         |           | * |        |          |
+-----------------------+---+---------+-----------+---+--------+----------+
| **4. Title and        |   |         |           | * |        |          |
| Subtitle**            |   |         |           | * |        |          |
|                       |   |         |           | 5 |        |          |
| > EVALUATION OF       |   |         |           | . |        |          |
| > LIGHTWEIGHT         |   |         |           | R |        |          |
| > MATERIAL CONCEPTS   |   |         |           | e |        |          |
| > FOR                 |   |         |           | p |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | t |        |          |
|                       |   |         |           | D |        |          |
|                       |   |         |           | a |        |          |
|                       |   |         |           | t |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | J |        |          |
|                       |   |         |           | u |        |          |
|                       |   |         |           | l |        |          |
|                       |   |         |           | y |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | 1 |        |          |
|                       |   |         |           | 9 |        |          |
|                       |   |         |           | 9 |        |          |
|                       |   |         |           | 7 |        |          |
+-----------------------+---+---------+-----------+---+--------+----------+
| > AIRCRAFT TURBINE    |   |         |           | * |        |          |
| > ENGINE ROTOR        |   |         |           | * |        |          |
| > FAILURE PROTECTION  |   |         |           | 6 |        |          |
|                       |   |         |           | . |        |          |
|                       |   |         |           | P |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | f |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | m |        |          |
|                       |   |         |           | i |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | g |        |          |
|                       |   |         |           | O |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | g |        |          |
|                       |   |         |           | a |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | i |        |          |
|                       |   |         |           | z |        |          |
|                       |   |         |           | a |        |          |
|                       |   |         |           | t |        |          |
|                       |   |         |           | i |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | C |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | d |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           | * |        |          |
+-----------------------+---+---------+-----------+---+--------+----------+
| **7. Author(s)**      |   |         |           | * |        |          |
|                       |   |         |           | * |        |          |
| > Dy D. Le            |   |         |           | 8 |        |          |
|                       |   |         |           | . |        |          |
|                       |   |         |           | P |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | f |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | m |        |          |
|                       |   |         |           | i |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | g |        |          |
|                       |   |         |           | O |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | g |        |          |
|                       |   |         |           | a |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | i |        |          |
|                       |   |         |           | z |        |          |
|                       |   |         |           | a |        |          |
|                       |   |         |           | t |        |          |
|                       |   |         |           | i |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | R |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | p |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | t |        |          |
|                       |   |         |           | N |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | . |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | A |        |          |
|                       |   |         |           | I |        |          |
|                       |   |         |           | R |        |          |
|                       |   |         |           | - |        |          |
|                       |   |         |           | 4 |        |          |
|                       |   |         |           | 4 |        |          |
|                       |   |         |           | 7 |        |          |
|                       |   |         |           | 2 |        |          |
|                       |   |         |           | 0 |        |          |
|                       |   |         |           | 0 |        |          |
|                       |   |         |           | P |        |          |
+-----------------------+---+---------+-----------+---+--------+----------+
| **9. Performing       |   |         |           | * |        |          |
| Organization Name and |   |         |           | * |        |          |
| Address**             |   |         |           | 1 |        |          |
|                       |   |         |           | 0 |        |          |
| > U.S. Army Research  |   |         |           | . |        |          |
| > Lab/Naval Air       |   |         |           | W |        |          |
| > Warfare Center      |   |         |           | o |        |          |
| > Aircraft            |   |         |           | r |        |          |
| > Division-Trenton    |   |         |           | k |        |          |
|                       |   |         |           | U |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | i |        |          |
|                       |   |         |           | t |        |          |
|                       |   |         |           | N |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | . |        |          |
|                       |   |         |           | ( |        |          |
|                       |   |         |           | T |        |          |
|                       |   |         |           | R |        |          |
|                       |   |         |           | A |        |          |
|                       |   |         |           | I |        |          |
|                       |   |         |           | S |        |          |
|                       |   |         |           | ) |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | 1 |        |          |
|                       |   |         |           | 0 |        |          |
|                       |   |         |           | 4 |        |          |
|                       |   |         |           | 7 |        |          |
+-----------------------+---+---------+-----------+---+--------+----------+
| > 1440 Parkway Ave.   |   |         |           | * |        |          |
| >                     |   |         |           | * |        |          |
| > Trenton, NJ         |   |         |           | 1 |        |          |
| > 08628-0176          |   |         |           | 1 |        |          |
|                       |   |         |           | . |        |          |
|                       |   |         |           | C |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | t |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | a |        |          |
|                       |   |         |           | c |        |          |
|                       |   |         |           | t |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | G |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | a |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | t |        |          |
|                       |   |         |           | N |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | . |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | I |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | t |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | a |        |          |
|                       |   |         |           | g |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | c |        |          |
|                       |   |         |           | y |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | A |        |          |
|                       |   |         |           | g |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | m |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | t |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | D |        |          |
|                       |   |         |           | T |        |          |
|                       |   |         |           | F |        |          |
|                       |   |         |           | A |        |          |
|                       |   |         |           | 0 |        |          |
|                       |   |         |           | 3 |        |          |
|                       |   |         |           | - |        |          |
|                       |   |         |           | 9 |        |          |
|                       |   |         |           | 5 |        |          |
|                       |   |         |           | - |        |          |
|                       |   |         |           | X |        |          |
|                       |   |         |           | - |        |          |
|                       |   |         |           | 9 |        |          |
|                       |   |         |           | 0 |        |          |
|                       |   |         |           | 0 |        |          |
|                       |   |         |           | 1 |        |          |
|                       |   |         |           | 0 |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | a |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | d |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | D |        |          |
|                       |   |         |           | T |        |          |
|                       |   |         |           | F |        |          |
|                       |   |         |           | A |        |          |
|                       |   |         |           | 0 |        |          |
|                       |   |         |           | 3 |        |          |
|                       |   |         |           | - |        |          |
|                       |   |         |           | 8 |        |          |
|                       |   |         |           | 8 |        |          |
|                       |   |         |           | - |        |          |
|                       |   |         |           | A |        |          |
|                       |   |         |           | - |        |          |
|                       |   |         |           | 0 |        |          |
|                       |   |         |           | 0 |        |          |
|                       |   |         |           | 0 |        |          |
|                       |   |         |           | 2 |        |          |
|                       |   |         |           | 9 |        |          |
+-----------------------+---+---------+-----------+---+--------+----------+
| **12. Sponsoring      |   |         |           | * |        |          |
| Agency Name and       |   |         |           | * |        |          |
| Address**             |   |         |           | 1 |        |          |
|                       |   |         |           | 3 |        |          |
| > U.S. Department of  |   |         |           | . |        |          |
| > Transportation and  |   |         |           | T |        |          |
| > U.S. Army Research  |   |         |           | y |        |          |
| > Laboratory          |   |         |           | p |        |          |
| >                     |   |         |           | e |        |          |
| > Federal Aviation    |   |         |           | o |        |          |
| > Administration      |   |         |           | f |        |          |
| > Arsenal Street      |   |         |           | R |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | p |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | t |        |          |
|                       |   |         |           | a |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | d |        |          |
|                       |   |         |           | P |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | i |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | d |        |          |
|                       |   |         |           | C |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | v |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | d |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | F |        |          |
|                       |   |         |           | i |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | a |        |          |
|                       |   |         |           | l |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | R |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | p |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | t |        |          |
+-----------------------+---+---------+-----------+---+--------+----------+
| > Atlantic City       |   |         |           | * |        |          |
| > International       |   |         |           | * |        |          |
| > Airport Watertown,  |   |         |           | 1 |        |          |
| > MA 02171-0001       |   |         |           | 4 |        |          |
| >                     |   |         |           | . |        |          |
| > New Jersey 08405    |   |         |           | S |        |          |
|                       |   |         |           | p |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | s |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | r |        |          |
|                       |   |         |           | i |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | g |        |          |
|                       |   |         |           | A |        |          |
|                       |   |         |           | g |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | n |        |          |
|                       |   |         |           | c |        |          |
|                       |   |         |           | y |        |          |
|                       |   |         |           | C |        |          |
|                       |   |         |           | o |        |          |
|                       |   |         |           | d |        |          |
|                       |   |         |           | e |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           | * |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | > |        |          |
|                       |   |         |           |   |        |          |
|                       |   |         |           | A |        |          |
|                       |   |         |           | A |        |          |
|                       |   |         |           | R |        |          |
|                       |   |         |           | - |        |          |
|                       |   |         |           | 4 |        |          |
|                       |   |         |           | 3 |        |          |
|                       |   |         |           | 0 |        |          |
+-----------------------+---+---------+-----------+---+--------+----------+
| **15. Supplementary   |   |         |           |   |        |          |
| Notes**               |   |         |           |   |        |          |
|                       |   |         |           |   |        |          |
| > The FAA William J.  |   |         |           |   |        |          |
| > Hughes Technical    |   |         |           |   |        |          |
| > Center COTR is Bill |   |         |           |   |        |          |
| > Emmerling, AAR-431. |   |         |           |   |        |          |
+-----------------------+---+---------+-----------+---+--------+----------+
| **16. Abstract**      |   |         |           |   |        |          |
|                       |   |         |           |   |        |          |
| > Results of the      |   |         |           |   |        |          |
| > evaluation of       |   |         |           |   |        |          |
| > lightweight         |   |         |           |   |        |          |
| > materials for       |   |         |           |   |        |          |
| > aircraft turbine    |   |         |           |   |        |          |
| > engine rotor        |   |         |           |   |        |          |
| > failure protection  |   |         |           |   |        |          |
| > are presented in    |   |         |           |   |        |          |
| > this report. The    |   |         |           |   |        |          |
| > program consisted   |   |         |           |   |        |          |
| > of two phases.      |   |         |           |   |        |          |
| > Phase 1 was an      |   |         |           |   |        |          |
| > evaluation of a     |   |         |           |   |        |          |
| > group of composite  |   |         |           |   |        |          |
| > materials which     |   |         |           |   |        |          |
| > could possibly      |   |         |           |   |        |          |
| > contain the impact  |   |         |           |   |        |          |
| > energies of 1.0 x   |   |         |           |   |        |          |
| > 10^6^ inch-pounds   |   |         |           |   |        |          |
| > generated by T53    |   |         |           |   |        |          |
| > rotor fragments.    |   |         |           |   |        |          |
| > Phase 2 refined     |   |         |           |   |        |          |
| > system composition  |   |         |           |   |        |          |
| > and weight of the   |   |         |           |   |        |          |
| > optimum materials   |   |         |           |   |        |          |
| > selected from phase |   |         |           |   |        |          |
| > 1 and determined    |   |         |           |   |        |          |
| > their performance   |   |         |           |   |        |          |
| > under elevated      |   |         |           |   |        |          |
| > temperatures. Based |   |         |           |   |        |          |
| > on the results of   |   |         |           |   |        |          |
| > phase 1, the        |   |         |           |   |        |          |
| > aluminum lined      |   |         |           |   |        |          |
| > fiberglass is the   |   |         |           |   |        |          |
| > best system, so     |   |         |           |   |        |          |
| > far. The Aramid     |   |         |           |   |        |          |
| > system with an      |   |         |           |   |        |          |
| > aluminum liner      |   |         |           |   |        |          |
| > performed almost as |   |         |           |   |        |          |
| > effective as        |   |         |           |   |        |          |
| > aluminum lined      |   |         |           |   |        |          |
| > fiberglass under    |   |         |           |   |        |          |
| > ambient conditions. |   |         |           |   |        |          |
| > Dry Kevlar          |   |         |           |   |        |          |
| > performed better    |   |         |           |   |        |          |
| > than Kevlar         |   |         |           |   |        |          |
| > impregnated with    |   |         |           |   |        |          |
| > phenolic resin.     |   |         |           |   |        |          |
| > Under elevated      |   |         |           |   |        |          |
| > temperatures, the   |   |         |           |   |        |          |
| > performances of the |   |         |           |   |        |          |
| > aluminum lined      |   |         |           |   |        |          |
| > fiberglass system,  |   |         |           |   |        |          |
| > based on energy per |   |         |           |   |        |          |
| > weight and          |   |         |           |   |        |          |
| > thickness, reduced  |   |         |           |   |        |          |
| > by 50 and 33        |   |         |           |   |        |          |
| > percent             |   |         |           |   |        |          |
| > respectively. An    |   |         |           |   |        |          |
| > increase of 92      |   |         |           |   |        |          |
| > percent in          |   |         |           |   |        |          |
| > containment ring    |   |         |           |   |        |          |
| > weight and 304      |   |         |           |   |        |          |
| > percent in its      |   |         |           |   |        |          |
| > thickness is        |   |         |           |   |        |          |
| > required to         |   |         |           |   |        |          |
| > compensate for the  |   |         |           |   |        |          |
| > degradation of the  |   |         |           |   |        |          |
| > fiberglass system   |   |         |           |   |        |          |
| > performance under   |   |         |           |   |        |          |
| > high temperatures.  |   |         |           |   |        |          |
| > Fabric composite    |   |         |           |   |        |          |
| > systems absorbed    |   |         |           |   |        |          |
| > the kinetic energy  |   |         |           |   |        |          |
| > of fragments        |   |         |           |   |        |          |
| > through elastic     |   |         |           |   |        |          |
| > deformation and     |   |         |           |   |        |          |
| > interlaminated      |   |         |           |   |        |          |
| > shear of composite  |   |         |           |   |        |          |
| > layers.             |   |         |           |   |        |          |
+-----------------------+---+---------+-----------+---+--------+----------+
| **17. Key Words**     |   |         | **18.     |   |        |          |
|                       |   |         | Dis       |   |        |          |
| > Rotor disc burst,   |   |         | tribution |   |        |          |
| > Containment ring    |   |         | St        |   |        |          |
| > ,Rotor fragment     |   |         | atement** |   |        |          |
| >                     |   |         |           |   |        |          |
| > Uncontained turbine |   |         | > This    |   |        |          |
| > engine failure,     |   |         | >         |   |        |          |
| > Tri-hub failure,    |   |         |  document |   |        |          |
| > Kevlar, Fiberglass, |   |         | > is      |   |        |          |
| > Aramid              |   |         | >         |   |        |          |
|                       |   |         | available |   |        |          |
|                       |   |         | > to the  |   |        |          |
|                       |   |         | > public  |   |        |          |
|                       |   |         | > through |   |        |          |
|                       |   |         | > the     |   |        |          |
|                       |   |         | >         |   |        |          |
|                       |   |         |  National |   |        |          |
|                       |   |         | >         |   |        |          |
|                       |   |         | Technical |   |        |          |
|                       |   |         | > In      |   |        |          |
|                       |   |         | formation |   |        |          |
|                       |   |         | >         |   |        |          |
|                       |   |         |  Service, |   |        |          |
|                       |   |         | > Spr     |   |        |          |
|                       |   |         | ingfield, |   |        |          |
|                       |   |         | >         |   |        |          |
|                       |   |         |  Virginia |   |        |          |
|                       |   |         | > 22161   |   |        |          |
+-----------------------+---+---------+-----------+---+--------+----------+
| **19. Security        |   | **20.   |           |   | **21.  | **22.    |
| Classif. (of this     |   | S       |           |   | No. of | Price**  |
| report)**             |   | ecurity |           |   | P      |          |
|                       |   | C       |           |   | ages** |          |
| Unclassified          |   | lassif. |           |   |        |          |
|                       |   | (of     |           |   | > 86   |          |
|                       |   | this    |           |   |        |          |
|                       |   | page)** |           |   |        |          |
|                       |   |         |           |   |        |          |
|                       |   | > Uncla |           |   |        |          |
|                       |   | ssified |           |   |        |          |
+-----------------------+---+---------+-----------+---+--------+----------+

**Form DOT F1700.7** **(8-72)** **Reproduction of completed page
authorized**

PREFACE

The entire program was sponsored by the FAA William J. Hughes Technical
Center, Atlantic City International Airport, New Jersey 08405. This
report was prepared by the Naval Air Warfare Center Aircraft Division,
Trenton, New Jersey 08628, according to the Interagency Agreement No.
DTFA03-95-X-90010 agreed upon by the William J. Hughes Technical Center
Atlantic City International Airport, NJ, and the Naval Air Warfare
Center Aircraft Division-Trenton, NJ (NAWCAD-TRN). Monsieurs Bruce
Fenton, Robert Pursel, John Reinhardt, and William Emmerling of the
William J. Hughes Technical Center served as FAA program monitors for
the program. Dr. Steve Petrie of the University of Massachusetts,
Lowell, Massachusetts 01854, and Monsieurs John Deluca, and Jay Connors
of the U.S. Army Research Laboratory (ARL), Aberdeen Proving Ground,
Maryland 21005, served as Army program monitors for the development and
fabrication of containment rings. Their contributions and assistance
during this program were greatly appreciated.

Program managers at NAWCAD-TRN who were responsible for this program
were James Salvino from 1989 through 1994 and Dy Le from 1994 to
completion. Project engineers assigned were Tracy Russo and Robert
Delucia.

The author would like to commend Monsieurs Edward Schaeffer, John
Grotheer, Glenn Myers, Bruce Rymovich, and Paul Lane, NAWCAD-TRN's
aircraft engine mechanics, for their hard work and dedication to the
program. This program would not have been successfully completed without
their professional support.

Rejected T53 second power turbine discs used in the burst tests were
provided by the Corpus Christi Army Depot, Corpus Christi, Texas 78419.
Ms. Robin Bonham processed and handled all disc shipments to NAWCAD-TRN.
Her assistance and contributions were essential to the success of the
program and were also greatly appreciated.

TABLE OF CONTENTS

Page

EXECUTIVE SUMMARY xi

1\. INTRODUCTION 1

2\. TEST PROGRAM 2

2.1 Material Development 2

2.2 Equipment Development 4

2.3 Ring Fabrication Technique 4

3\. ROTOR SPIN FACILITY 4

3.1 RSF Mission 4

3.2 RSF Description 5

4\. DESIGN OF TRI-HUB DISC FAILURE 6

4.1 Fragment Energy 6

4.2 Rotor Fragment Generator Analysis 9

5\. METHOD OF TEST 9

6\. CONTAINMENT RING DAMAGE ASSESSMENT AND TEST RESULTS 13

7\. CONCLUSIONS 64

8\. REFERENCES 64

APPENDICES

AKINETIC ENERGY OF DISC FRAGMENTS

BROTOR FRAGMENT GENERATOR ANALYSIS

LIST OF FIGURES

Figure Page

1 NAWCAD-TRN Largest Spin Chamber 6

2 T53 Power TurbineThree Fragment Modification 7

3 Distribution of Translational and Rotational Kinetic Energy of Rotor
Burst

Fragment as a Function of Fragment Angle (*φ*) 8

4 Sequence of Rotor Failure Measured in Milliseconds 10

5 Typical Plot of Containment Ring Burst Test 10

6 A Typical Containment Ring and a Modified T53 Turbine 11

7 A Typical Containment Ring Burst Test Setup (Radial Direction) 11

8 A Typical Containment Ring Burst Test Setup (Axial Direction) 12

9 A Typical Deformed Containment Ring After Burst 12

10 Failed Rotor Fragments 13

11 Containment Ring Perforation Failure 14

12 Containment Ring Tensile Failure 15

13 Unraveled Effect of Fabric Containment Ring 15

14 Posttest Pictures of Rings 31, 35, 36, and 37 20

15 Failure Event of Rings 31 and 36 21

16 Group 1Fiberglass-Aluminum 22

17 Posttest Pictures of Rings 2, 10, and 20 23

18 Failure Event of Ring 10 24

19 Group 2Fiberglass-Phenolic 25

20 Posttest Pictures of Rings 3, 9, and 17 26

21 Failure Event of Rings 3 and 9 27

22 Failure Event of Rings 17 and 24 28

23 Failure Event and Posttest Pictures of Ring 28 29

24 Group 3Fiberglass-Polyester 30

25 Posttest Pictures of Rings 22 and 30 31

26 Failure Event of Ring 30 32

27 Group 4Dry Kevlar 29 33

28 Posttest Pictures of Rings 29, 32, 33, and 34 34

29 Failure Event of Ring 32 35

30 Failure Event of Rings 33 and 34 36

31 Group 5Dry Kevlar 29-Aluminum 37

32 Posttest Pictures of Rings 1, 11, and 16 38

33 Failure Event of Rings 1 and 11 39

34 Failure Event of Rings 16 and 25 40

35 Group 6Kevlar 29-Phenolic 41

36 Posttest Pictures of Rings 6, 13, and 21 42

37 Failure Event of Rings 13 and 21 43

38 Group 7Steel-Fiberglass-Phenolic 44

39 Posttest Pictures of Rings 7, 14, and 19 45

40 Failure Event of Rings 7 and 19 46

41 Group 8Steel-Fiberglass-Polyester 47

42 Posttest Pictures of Rings 4, 12, and 15 49

43 Failure Event of Rings 4 and 12 50

44 Failure Event of Ring 15 51

45 Group 9Titanium-Dry Kevlar-Phenolic 52

46 Posttest Pictures of Rings 5, 8, and 18 53

47 Failure Event of Ring 18 54

48 Group 10Titanium 55

49 Weight Increase Versus Penetrating Duration 56

50 Thickness Increase Versus Penetrating Duration 57

51 Posttest Pictures of Ring 38 61

52 Failure Event of Ring 38 62

53 Failure Event and Pre/Posttest Pictures of Ring 40 63

LIST OF TABLES

Table Page

1 Initial Containment Ring Property Characteristics 3

2 FAA/Army Composite Materials 17

3 FAA/Army Composite Materials Groups 18

4 FAA/Army Composite Material Rings (Contained All Fragments) 19

5 Rankings of Containment Rings Based on Energy Per Weight

(Contained All Fragments) 58

6 Rankings of Containment Rings Based on Energy Per Thickness

(Contained All Fragments) 58

7 Combined Rankings of Containment Rings (Contained All Fragments) 59

8 Heated Containment Rings 60

9 Heated Containment Ring Performance (Contained All Fragments) 60

EXECUTIVE SUMMARY

The Federal Aviation Administration William J. Hughes Technical Center,
Atlantic City International Airport, NJ, and the U.S. Army Research
Laboratory (ARL), Watertown, Massachusetts, conducted research and
development under an interagency agreement to identify the
state-of-the-art lightweight material concepts that could provide
suitable containment and/or isolation from the worst case small turbine
engine rotor disc failure hazard. The Naval Air Warfare Center Aircraft
Division, Trenton, NJ, was tasked by the William J. Hughes Technical
Center and ARL to conduct rotor disc burst containment tests on the
containment rings designed and fabricated by ARL. A fully bladed
Textron-Lycoming T53-L-11 second stage engine power turbine rotor, was
designed and modified to fail into three fragments in order to evaluate
the containment materials. This program consisted of two phases:

1.  The purpose of phase 1 was to screen a group of composite materials
    which possibly would be capable of containing the impact energies of
    1.0 x 10^6^ inch-pounds generated by T53 rotor fragments in the
    NAWCAD-TRN rotor spin chamber under the ambient condition. The
    results obtained from phase 1 were incorporated into phase 2.

2.  The purpose of phase 2 was to refine system composition and weight
    of the materials selected from phase 1 to the minimum for the
    designated protection level under predetermined elevated
    temperatures. The service temperature required for the selected
    materials was between 500 and 1,000°F. The selected candidate
    materials, screened from phase 1, were experimentally evaluated as
    panels by high energy impact tests and later as cylindrical ring
    specimens in the NAWCAD-TRN rotor spin chamber under the elevated
    temperature of 500°F or higher.

# 1. INTRODUCTION.

The Naval Air Warfare Center Aircraft Division located in Trenton, New
Jersey, was tasked by the FAA William J. Hughes Technical Center and the
U.S. Army Research Laboratory to conduct the engine rotor containment
tests in its rotor spin chamber. This program was sponsored by the
William J. Hughes Technical Center under the Interagency Agreement
DTFA03-95-X-90010 and DTFA03-88-A-00029. The purpose was to identify the
state-of-the-art lightweight materials which could provide suitable
containment and/or isolation from the worst case small turbine engine
rotor failure hazard. These materials might be considered for possible
use in helicopter turbine engine rotor containment structures.

Uncontained failure of engine rotating components in turbine engine
aircraft is considered a serious safety hazard to occupants and to the
aircraft itself. Rotating components include turbine, compressor, and
fan disc, as well as blades and other rotating components. They can
release high-energy fragments which are capable of penetrating the
engine cowling and damaging the fuel tank, hydraulic lines, auxiliary
power units, and other accessories.

According to the Aerospace Information Report 4003 (AIR-4003) prepared
by the Society of Automobile Engineers (SAE) in 1987, there were a total
of 315 uncontained rotor failures from 1976 to 1983 in commercial,
general, and rotorcraft aviation. For events causing significant and
severe commercial transport aircraft damage, 52 percent of uncontained
rotor failures recorded were due to discs; 2 percent were caused by fan
blades. In general aviation, two incidents were due to turbine blades
and three were from turbine discs. In rotorcraft aviation, 93 percent of
uncontained failures which resulted in significant and severe aircraft
damage were due to discs and spacers.

The uncontained failure of a gas turbine engine rotor is defined as a
rotor failure that produces fragments which penetrate and escape the
confines of the engine casing. Based on field experience in the past,
aircraft engine turbine and compressor discs usually fail into three
fragments (tri-hub failure), approximately 120 degrees apart.

The William J. Hughes Technical Center, recognizing the threat,
established the Aircraft Catastrophic Failure Prevention Research
Program in complying with the Omnibus Reconciliation Act of 1990. This
act requires that the FAA develop technologies and methods to assess the
risk and to prevent defects, failures, and malfunctions of products,
parts, processes, and articles manufactured for use in aircraft,
engines, propellers, and appliances which could result in a catastrophic
failure of an aircraft. In the area of turbine engine failure
prevention, three tasks have been identified and are being performed:
(1) failure characterization, (2) vulnerability assessment, and (3)
mitigation.

Tasks 1 and 2 were not directly performed by NAWCAD-TRN and ARL and are
not discussed in this report. The goals of task 3 include the
development of analytical models which would simulate and evaluate the
effectiveness of containment and shielding materials. Under the same
task a parallel research effort is the evaluation of light weight
ballistic armor materials and its technology to select materials that
are cost-effective and, yet, are capable of containing or mitigating the
potential damage of burst rotor fragments.

In response to the William J. Hughes Technical Center's initiative in
the hazard threat protection area, task 3, NAWCAD-TRN and ARL proposed a
composite material research and evaluation program which was divided
into two phases. The first phase was to screen a group of material
systems which consisted of high-temperature, ballistic, fiber materials.
Some of those composite fiber materials, with different weaving
patterns, were combined with different resins and/or metallic alloys.
More than two composite material systems were selected for the second
phase of the program when system composition and weight were refined to
the minimum for the designated protection level. In the second phase,
selected composite material systems were tested under a minimum
temperature of 500 °F.

# 2. TEST PROGRAM.

Materials development, equipment development, fabrication technique, and
testing of the generic containment rings against the fully bladed T53
second stage power turbine were critical and fully studied in this
project. ARL developed the materials and fabrication techniques.
NAWCAD-TRN performed all the spin burst tests of ARL's containment rings
in a vacuum spin chamber. NAWCAD-TRN was also tasked, at the conclusion
of the test program, to analyze test results and write a final report
for FAA publication. Three testing techniques were performed to
determine the capability of a material for containing turbine rotor
fragments: subscale rotor fragment simulation testing, full-scale
simulation testing, and spin testing. A detailed explanation of the
first two techniques may be found in reference 1.

## 2.1 Material Development.

During the subscale rotor fragment simulation testing phase, a standard
ballistic V~50~ impact criterion and test were used. This subscale test
was selected because it was cost-effective and widely used. The baseline
V~50~ ballistic criterion, a velocity for which a projectile would have
50 percent probability of penetrating and perforating a certain
containment system thickness, was derived. Based on the previous
NAWCAD-TRN's spin test data, a cast steel ring 1.0 inch long and 0.625
inch thick is capable of containing all rotor fragments generated from
the General Electric T58 power turbine. This initial containment value,
during this analytical process, was used. Existing ballistic data,
experimentally determined by Mascianica \[2\] was also extrapolated to
predict a V~50~ criterion of 2,000 feet per second. Before conducting a
ballistic test of flat panels of candidate materials, a mathematical
model using similitude analysis was developed to obtain a set of scaled
factors of the actual rotor spin burst test conditions. The kinematic
properties of the T53 second stage power turbine and of the prototype,
the properties of candidate materials, and the responses of containment
ring materials upon impact were incorporated in the analysis. The scaled
factors obtained from the similitude analysis were then applied to the
model for a ballistic test. A 20-mm smooth bore gun barrel and 20-mm
masses which simulated the T53 turbine fragments were used for the
subscale tests. The results of the tests were used to estimate the areal
density required for the rotor spin burst tests conducted at NAWCAD-TRN.
A detailed description of the mathematical model and V~50~ subscale
tests are explained in reference 1.

Based on the results from the V~50~ subscale tests, a full-scale
projectile testing was developed as a screening containment test before
rotor spin burst testing began. The work involved single and triple full
mass projectiles utilizing explosive devices. A detailed procedure and
description of the experiments are explained in reference 1.

Seven general candidate material systems which include phenolic and
polyester thermosetting resins were selected and compared against the
all cast steel system for the full-scale projectile testing, table 1.
Titanium 6AL-4V was the only metallic material which would be evaluated
against steel due to lighter weight. High-strength fiberglass (S-2) and
aramid (Kevlar 29) materials which have been extensively used in armor
protection systems were also selected. Steel material was also used as a
liner for fiberglass and phenolic and for fiberglass and polyester
systems. Titanium was additionally used as a liner with aramid and
phenolic system. A separate system which contained aramid impregnated
with phenolic was also made. Two fiberglass composite systems were
created: fiberglass fibers impregnated with polyester and fiberglass
fibers impregnated with phenolic resin. Polyester and phenolic resin
temperature capability is rated at approximately 350°F.

TABLE 1. INITIAL CONTAINMENT RING PROPERTY CHARACTERISTICS

  ---------------------------- --------- ----------- ----------- --------- ----------- -------------- ---------- -------------
  Materials                    Areal                 Thickness             Estimated                  Weight     
                               Density               (in)                  Weight                     Saving (%) 
                               (psf)                                       (lbs)                                 

  Cast Steel (300 BHN)         25.6                  0.625                 75.4                       Baseline   

  Titanium (6AL-4V)            14.0                  0.620                 41.2                       45.3       

  Steel-Fiberglass-Phenolic    19.3                  0.953                 56.8                       24.7       

  Steel-Fiberglass-Polyester   19.3                  0.953                 56.8                       24.7       

  Titanium-Aramid-Phenolic     12.4                  1.110                 36.4                       51.7       

  Aramid-Phenolic              10.7                  1.600                 31.5                       58.2       

  Fiberglass-Polyester         15.0                  1.500                 44.2                       41.4       

  Fiberglass-Phenolic                    15.0                    1.500                 44.2                      41.4
  ---------------------------- --------- ----------- ----------- --------- ----------- -------------- ---------- -------------

Cast steel, 300 BHN, and titanium 6AL-4V were the metallic materials
used in some containment rings and as liners in other fabric systems.

Aramid material selected for testing was 1500 denier Kevlar 29, 35 x 35,
2 x 2, 13.6 ounce per square yard basket-weave fabric. Three thousand
denier Kevlar 29, 17 x 17, 13.6 ounce per square yard plain weave fabric
was also used for testing.

The fiberglass material was a 24 ounce per square yard woven roving
produced with high-strength S-2 grade fiberglass.

Table 1 contains the areal density and containment thickness results
from the subscale and full-scale simulation testing.

## 2.2 Equipment Development.

Several types of equipment were utilized to fabricate containment rings
for testing at NAWCAD-TRN. A McClean Anderson model W-60, three-axis
filament winder was used because of its large mandrel capacity. A
different mandrel was designed and built to wind all composite
containment rings which were 14 inches in diameter and 9 inches in axial
length. It was capable of fabricating the three test specimens mentioned
earlier. This mandrel could withstand the 100 pounds per square inch
autoclave pressure required for processing the phenolic matrix
materials. A fabric dispensing stand was also built to dispense the
preimpregnated fabric with controllable tension. A compaction stand was
constructed to improve the compaction of the materials as they were fed
to the winding mandrel. Finally, a fabric splitting stand was also built
to slit the preimpregnated fabric from its original width to the width
required for the containment rings to be tested at NAWCAD-TRN rotor spin
facility (RSF). Detail design, machining, and operation of these items
of equipment are explained in reference 1.

## 2.3 Ring Fabrication Technique.

Composite containment rings were fabricated from preimpregnated fabric.
This was because fabric is easier to construct, and their ballistics
properties are superior to those of filament wound yarns. The critical
parameter is the ring thickness which must be precisely controlled to
achieve uniformity. Two characteristics were required for achieving
uniformity of ring thickness: controllable tension of fabric and fabric
movement while being wound.

Several fabrication techniques were developed and attempted before
making the test containment rings. Generally, the composite cylinders
would have to be completely wound and cured before being machined to a
final length. Wound and cured cylinders of fabric materials were then
placed on the lathe and cut by a diamond cutting wheel to the exact
length required.

The metallic systems were fabricated and machined to their final
dimensions without a lengthy process as that of fabric systems. The
metal lined composite containment rings were fabricated differently.
One-sixteenth-inch-thick metallic liners were machined to their final
dimensions and then were used as winding mandrels upon which the fabric
materials were wound. The metallic liners remained within the composite
system.

The details of the technique for each system is explained by Deluca
\[1\].

# 3. ROTOR SPIN FACILITY (RSF).

## 3.1 RSF Mission. 

The rotor spin facility at NAWCAD-TRN features the U.S. Navy's largest
spin chamber. The RSF's general mission is to provide the experimental
support for the engine rotor stress analysis, rotor low- and high-cycle
fatigue evaluation, rotor structural integrity investigation, rotor
burst characterization studies, and blade and disk containment
evaluation.

The U.S. Navy aircraft propulsion component tests are conducted, under
simulated engine conditions, to evaluate rotor stress distribution,
critical stress locations, and crack initiation and propagation
phenomena. RSF performs spin testing to evaluate exploratory and
advanced development concepts as well as to verify component life
prediction methodology developed by engine manufacturers. Spin testing
of the U.S. Navy propulsion rotating components such as low-cycle
fatigue and overspeed tests is used for qualification and release to
production. Rotor vibration and diagnostics can be studied using a
sophisticated diagnostic vibration instrument system. Centrifuge testing
can be used to evaluate new materials for rotating components as well as
for commercial containment applications.

## 3.2 RSF Description. 

The facility has four vertical vacuum chambers which have different
sizes to accommodate various sizes of rotor assemblies. The spin chamber
has a removable lid which when removed allows access to the interior.
The selected drive turbine and test vehicle assembly can be configured
and built under the lid overhung from the steel tower located in the
work-built area. The chamber lid and wall can accommodate various sizes
of drive turbines, instrumentation sensors, and other accessories. Other
component accessories such as high-speed cameras can be adapted to the
spin chamber wall. A typical spin chamber has an outer cylindrical steel
shell which has several ports, an air space, an inner laminated steel
liner, and an inner containment chamber liner. Materials for the inner
containment chamber liner may be wood, lead, or aluminum. The outer
shell and inner liners are capable of absorbing up to 100 million in-lbs
of the energy generated from rotor burst fragments when testing.
Although all vacuum chambers can be modified to adapt various auxiliary
equipment, the largest chamber is the only one which has been modified
to accommodate a high-speed camera for the FAA containment burst tests.
Figure 1 is the schematic of the largest chamber, 110 inches in working
diameter and 72 inches in height. RSF is equipped with four oil seal
vacuum pumps ranging from 15 to 20 hp. Each vacuum pump has the capacity
of providing a spin chamber vacuum in millitorr. Air for the spin
testing is provided by the axial/centrifugal and reciprocating air
compressors which are capable of producing air flow rates from 750 to
4,050 cubic feet per minute (cfm).

The NEFF Series 4000 Differential Multiplexer is a complete high-speed
analog data application system designed to capture real-time test data
and output them to the RSF automatic data acquisition and computer
system for processing. The system is capable of allowing simultaneous
multiple tests and unattended operations and providing up to 256
channels. Data sampling and recording are performed at a controlled rate
of 100 samples per second (s/s).

RSF is also equipped with four state-of-the-art strip chart recording
and analyzing devices. Each system is capable of recording up to 8
channels and can be upgraded to a maximum of 32 channels. Failure events
can be captured, plotted, and automatically stored in the 1-gigabyte
hard disk drive. Each system has 16 megabytes of random access memory.

![](media/image2.emf){width="4.575694444444444in"
height="3.0076388888888888in"}FIGURE 1. NAWCAD-TRN LARGEST SPIN CHAMBER

# 4. DESIGN OF TRI-HUB DISC FAILURE.

## 4.1 Fragment Energy.

In order to evaluate the containment rings, fully bladed unserviceable
Textron-Lycoming second power turbine wheels of the T53-L-13 engine were
analyzed. They were designed to fail into three equal fragments at
approximately 120 degrees apart and at a speed which was capable of
producing a specific amount of kinetic energy at burst. The tri-hub
rotor burst was designed to simulate the worst case failure of an actual
turbine engine rotor. The burst energy of the rotor was selected to be
1.0 x 10^6^ in-lbs which approximated the amount of the total kinetic
energy produced by a turbine rotor of a medium-size commercial
turboshaft engine. The calculated speed of this particular rotor, which
produced 1.0 x 10^6^ in-lbs of kinetic energy at burst, equated to
approximately 20,400 rpm using equation 23 of appendix A. Figure 2 is a
drawing of the T53-L-13 modified turbine rotor with its material
properties. The slot terminal radius (STR) or b-cut was defined as the
distance from the center of the turbine rotor to the end of the cut.
Appendix A shows the derivations for the kinetic energy of disk
fragments having a sector angle *φ*.

DISK BLADES![](media/image3.emf){width="4.9222222222222225in"
height="3.707638888888889in"}

ROTOR: T53-L-13 Power Turbine Materials AMS-5509 AMS-5391

DESCRIPTION: 3 Fragment Modification PROPERTIES

ROTOR WEIGHT: 10.80 lbs SU (KPSI): 175 110 (min)

FRAGMENT CENTROIDAL DISTANCE: 3.235 inches SY (KPSI): 125 100 (min)

FRAGMENT INERTIA (1/3): 54.61 lb-in^2^ EU, t\> 0.032 inch 8% 3%

FIGURE 2. T53 POWER TURBINETHREE FRAGMENT MODIFICATION

Figure 3, which comes from equations 22-25 in appendix A, shows that the
maximum translational kinetic energy (KE~t~) of a fragment is obtained
when the fragment sector angle is equal to 133.6 degrees. The total
KE~t~ at this angle, however, is lower than the total KE~t~ as the
sector angle becomes smaller or the number of fragments increases. In
the design of the disk failure for the containment tests, the severe
translational kinetic energy produced by a 120-degree disk fragment is
interesting since the difference of KE~t~s between the 120 and 133.6
degrees is insignificant. At the moment of the disk failure, KE~t~ of a
one-third fragment reaches 21% and the rotational kinetic energy (KE~r~)
accounts for 12.3% of the total kinetic energy (KE). However, because of
the fragment energy loss due to the friction from the rubbing of the
disk against the containment ring, only approximately one-half (6.1%) of
the rotational kinetic energy exists. Therefore, most of the damage to
engine casings or other components is caused by the translational
kinetic energy of the fragments. It should also be noted from figure 3
that the translational kinetic energy decreases and reaches zero as the
fragment sector angle increases and reaches 360°. At this point, the
total energy comes completely from the rotational kinetic energy. On the
other hand, as the number of fragments increases, the rotational kinetic
energy of a fragment decreases and becomes small. KE~t~, however,
becomes larger and approaches its limit of 92.6%. At this limit KE~r~ is
very small.

FIGURE 3. DISTRIBUTION OF TRANSLATIONAL AND ROTATIONAL KINETIC
![](media/image4.emf){width="6.065277777777778in"
height="5.756944444444445in"}

> ENERGY OF ROTOR BURST FRAGMENT AS A FUNCTION OF FRAGMENT ANGLE (*φ*)

## 4.2 Rotor Fragment Generator Analysis. 

Most of the experimental work on the rotor fragment generator had been
performed at NAWCAD-TRN. Appendix B shows the detail of the analysis,
extracted from reference 3, to come up with the notches to fail the T53
second power turbine into three equal pieces at a predetermined speed.

# 5. METHOD OF TEST.

A fully bladed Textron-Lycoming T53 second power turbine rotor, which
was modified to fail into three equal fragments, was mounted to the spin
chamber lid and connected to a Barbour Stockwell 8-inch air drive
turbine by a Trans Torque coupling and an eight-inch drive spindle. The
containment ring, 9 inches in axial length and 15 inches in inner
diameter, designed and fabricated by ARL was freely suspended from
mounting brackets and was concentrically positioned around the T53
engine power turbine rotor. Reflective tape was used on the bottom of
the containment ring to illuminate the ring circumference and improve
its dynamic images on 35-mm film when burst. The axial midsection of the
ring was positioned to coincide with the rotor plane of rotation, and
the radial clearance between the tip of the rotor blades and inner
diametrical surface of containment ring was approximately 0.5 inch.

Figure 1 shows a typical test setup for the containment tests. The
mounted rotor was placed inside the spin chamber which was evacuated to
approximately 8 Torrs. The rotor was then accelerated to the burst speed
of 20,400 rpm. To record the failure event on film, parallel foil
stripes were attached on the inner perimeter of a containment ring in
the plane of disc rotation. The lights were flashed when the parallel
foils stripes were shorted by a rotor fragment upon failure. Two
12-million-candle power lights were used for the exposure. A high-speed
framing camera, which was mounted through a port on the side of the spin
chamber, was focused on the surface of a mirror which angled at 45
degrees and viewed the event from the bottom of the chamber. The spin
chamber was completely dark with the camera aperture fully opened and
the camera drum rotating at approximately 13,000 frames per second. When
a failure occurred, the rotor released fragments made contact with the
foil stripes on the inner surface of the ring. The contact interrupted
the low voltage signal of the trip circuit which engaged the strobe
lights thereby causing the failure events to be captured on film. Figure
4 is the typical sequence of the rotor failure measured in milliseconds
just after the impact. The rotor speed was monitored by two independent
magnetic pickups and displayed on the digital tachometers and graphic
display terminals in the RSF control room. All parameters were visually
monitored in the control room and recorded on a magnetic tape by the
automatic data acquisition and processing system at a rate of 100
samples per second. Figure 5 is a typical plot of the speed versus time.
The duration of the test normally lasted less than seventy seconds. At
burst, a sudden drop of the load caused a jump in the speed of the drive
turbine momentarily before the drive turbine sharply decelerated as seen
in figure 5. Figure 6 shows a pretest picture of the fiberglass-phenolic
ring. Figure 7 shows the pretest setup of the containment burst test
taken in the radial direction of the ring. Figure 8 shows the pretest
setup taken in the axial direction from the bottom of the ring. Notice
the reflective tape at the bottom of the ring to make the
circumferential cross section of the ring visible during burst event.
Figure 9 is the picture of the containment ring and rotor fragments
after failure. Figure 10 shows the picture of three equal pieces of
failed rotor fragments.

FIGURE 4. SEQUENCE OF ROTOR FAILURE MEASURED IN MILLISECONDS
(MS)![](media/image5.emf){width="5.845833333333333in"
height="3.683333333333333in"}

![](media/image6.emf){width="6.063888888888889in"
height="3.2645833333333334in"}

FIGURE 5. TYPICAL PLOT OF THE CONTAINMENT RING BURST TEST

![](media/image7.emf){width="4.620138888888889in"
height="3.657638888888889in"}

FIGURE 6. A TYPICAL CONTAINMENT RING AND A MODIFIED T53 TURBINE

![](media/image8.emf){width="3.151388888888889in"
height="2.446527777777778in"}

FIGURE 7. A TYPICAL CONTAINMENT RING BURST TEST SETUP (RADIAL

> DIRECTION)

![](media/image9.emf){width="5.1in" height="3.959722222222222in"}

FIGURE 8. A TYPICAL CONTAINMENT RING BURST TEST SETUP (AXIAL

> DIRECTION)

FIGURE 9. A TYPICAL DEFORMED CONTAINMENT RING AFTER
BURST![](media/image10.emf){width="4.717361111111111in"
height="3.6625in"}

![](media/image11.emf){width="4.715277777777778in"
height="3.745833333333333in"}

FIGURE 10. FAILED ROTOR FRAGMENTS

For heated burst tests in the range of 500-1,000°F, high-temperature and
high-impedance silicon based adhesive was used to attach an aluminum
foil stripe on the inner perimeter of the containment ring. Six
Thermolyne Briskheat flexible electric heating tapes, four 620-watt, and
two 836-watt tapes were used to cover the outer surface of the
containment ring in the area where it would be in the same plane of disc
rotation. Three J-typed thermocouples were installed. One thermocouple
was attached on the inner surface of the containment ring. The second
thermocouple was embedded in the middle of the ring and was on the same
plane of rotation of the T53 rotor. The third thermocouple was attached
on or close to the outer surface of the ring. Heat soaking was done
under the vacuum. As soon as the whole ring temperature reached between
500-1,000°F, air drive would be introduced into the drive system to
accelerate the T53 rotor to 20,400 rpm when the rotor would burst into
three equal fragments.

# 6. CONTAINMENT RING DAMAGE ASSESSMENTS AND TEST RESULTS.

When a fully bladed disc burst, the containment ring might or might not
contain all fragments. Sometimes, some of the blade debris escaped and
penetrated the containment ring. This is due to the fact that the ring
might not contain small and sharp-edge blade fragments because of its
smaller local impact area. However, these blade debris were so small
compared to the disc fragments that the residual energy might be
insignificant. These debris might, hence, present no severe threat to
the surrounding accessories.

Another phenomenon was that, during the burst event, blades were pushed
through the rings by impacting rotor disc fragments. The blades could
have penetrated through the containment ring thickness, but the rotor
fragment might only embed inside the ring. Under these two situations,
the ring would be considered to contain all disc fragments.

A thin aluminum sheet witness ring was used for each test to record the
trajectory of rotor disc fragments which penetrated and escaped the
containment ring. Sometimes, a fragment at burst impacted the inner ring
surface, flipped over the top of the ring, penetrated the witness ring,
and landed on the chamber floor outside the deformed ring.

The metallic and fiber composite material systems behaved differently
upon being impacted by rotor fragments. All metallic material systems
absorbed the kinetic energy of fragments through permanent deformation
and failed either in perforation or in tensile as shown in figures 11
and 12. The fiber composite material systems, however, absorbed the
kinetic energy of fragments through elastic deformation and
interlaminated shear of composite layers. No evidence of tensile failure
of fibers was found in tested fabric rings.

![](media/image12.emf){width="4.5472222222222225in"
height="3.5506944444444444in"}

FIGURE 11. CONTAINMENT RING PERFORATION FAILURE

In the fiber composite material systems, when the fragments were
impacting the inner surface of the fabric ring, they were still rotating
and tended to unravel the wraps or layers in the direction\
of their rotation. Because of this phenomenon, fabric layers were
wrapped in the opposite direction of rotor rotation. This measure,
however, did not eliminate the unraveling effect of the dry fabric
containment ring as shown in figure 13.

FIGURE 12. CONTAINMENT RING TENSILE FAILURE (SOURCE: SALVINO
1977)![](media/image13.emf){width="5.079166666666667in"
height="2.6256944444444446in"}

![](media/image14.emf){width="4.996527777777778in"
height="3.6319444444444446in"}

FIGURE 13. UNRAVELED EFFECT OF FABRIC CONTAINMENT RING

Another observation during testing is that, sometimes, high-speed
photographs taken during the burst event of the fiber composite systems
were not as definite and clear as that of all metallic systems. This is
due to the small debris generated from the fabric containment ring.

The test results of candidate materials were analyzed and ranked in the
order of their capability to contain the burst energy of rotor disk
fragments. Containment is defined as the capability of the ring to fully
contain all rotor fragments. The process is to define the threshold
containment capability of each group of candidate material systems. This
could be done by varying the weight, thickness, or the number of wraps
of a candidate system until a system would contain all rotor fragments.
However, since the burst speed was not exactly the same on every test, a
containment ring system, in a group, which contained all fragments and
provided the highest energy per weight was used for ranking. Two
parameters which were not considered in the ranking were the number of
wraps and weaving patterns due to insufficient data and records
available.

Ranking was based on the energy per normalized weight (E/w~t~), energy
per thickness (E/t), and the combination of the energy per normalized
weight and the energy per thickness. Containment ring normalized weight
was obtained by multiplying the ratio of its weight per actual axial
length to 9 inches. In aircraft design and application, weight is one of
the critical criteria. The normalized weight of containment rings,
therefore, would be of primary interest. The condition for the test
results to be valid was that the generated energy must be greater than
925 x 10^3^ in-lbs and less than 1,060 x 10^3^ in-lbs. This range is
based on the average burst energy of 992 x 10^3^ ± 67 x 10^3^ in-lbs for
all tests conducted at NAWCAD-TRN. If the generated energy is greater
than 1,060 x 10^3^ in-lbs and the ring contained all fragments, the test
was valid and included in the result.

Ranking was done by screening out all candidate systems which contained
all rotor fragments. There were a total of 24 systems which met the
containment criterion. A system which contained a threshold
configuration or highest energy in each group was selected. This process
gave ten different systems which contained all fragments. The system
that had a highest energy per weight or energy per thickness, in this
group of ten candidates, would be given a rank of ten. The containment
ring material or composite system that had the highest weight ranking
would be the best system. The system that had a lowest energy per weight
or energy per thickness would be given a rank of one. A combined ranking
per weight and per thickness could be obtained by multiplying the weight
ranking of a system to its thickness ranking.

Table 2 shows all candidate systems with their characteristics and
performance which had been tested in chronological order. Table 3 shows
the results of containment tests, contained or not contained, of
candidate composite materials and metals tested in group order. There
were a total of ten groups. Table 4 shows rings which contained all
rotor fragments.

TABLE 2. FAA/ARMY COMPOSITE MATERIALS

<table style="width:100%;">
<colgroup>
<col style="width: 5%" />
<col style="width: 21%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 10%" />
<col style="width: 10%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 9%" />
<col style="width: 8%" />
</colgroup>
<tbody>
<tr class="odd">
<td>Ring No.</td>
<td>Materials</td>
<td><p>Weight</p>
<p>(lbs)</p></td>
<td><p>Normal-ized</p>
<p>Weight</p>
<p>(lbs)</p></td>
<td><p>Radial Thickness</p>
<p>(in)</p></td>
<td><p>Axial Length</p>
<p>(in)</p></td>
<td>No. of High-Speed Photos</td>
<td>Failed Speed (rpm)</td>
<td><p>Contained (C) or Not Contained</p>
<p>(NC)</p></td>
<td><p>Test Temp-erature</p>
<p>(°F)</p></td>
</tr>
<tr class="even">
<td>1</td>
<td>Kevlar 29-Phenolic</td>
<td>32.00</td>
<td>28.83</td>
<td>1.62</td>
<td>9.99</td>
<td>38</td>
<td>20400</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>2</td>
<td>Fiberglass-Phenolic</td>
<td>48.25</td>
<td>46.84</td>
<td>1.63</td>
<td>9.27</td>
<td>0</td>
<td>20400</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>3</td>
<td>Fiberglass-Polyester</td>
<td>49.00</td>
<td>47.52</td>
<td>1.65</td>
<td>9.28</td>
<td>44</td>
<td>20945</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>4</td>
<td>Ti-Kevlar-Phenolic</td>
<td>37.25</td>
<td>37.13</td>
<td>1.10</td>
<td>9.03</td>
<td>42</td>
<td>20700</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>5</td>
<td>Titanium (6A14V)</td>
<td>44.00</td>
<td>43.95</td>
<td>0.62</td>
<td>9.01</td>
<td>1</td>
<td>20550</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>6</td>
<td>Steel-Fiberglass-Phenolic</td>
<td>60.00</td>
<td>58.82</td>
<td>1.00</td>
<td>9.18</td>
<td>1</td>
<td>21400</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>7</td>
<td>Steel-Fiberglass-Polyester</td>
<td>65.75</td>
<td>63.90</td>
<td>1.20</td>
<td>9.26</td>
<td>28</td>
<td>20700</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>8</td>
<td>Titanium (6A14V)</td>
<td>27.25</td>
<td>26.37</td>
<td>0.40</td>
<td>9.30</td>
<td>1</td>
<td>20300</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>9</td>
<td>Fiberglass-Polyester</td>
<td>36.75</td>
<td>36.51</td>
<td>1.18</td>
<td>9.06</td>
<td>40</td>
<td>20400</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>10</td>
<td>Fiberglass-Phenolic</td>
<td>34.00</td>
<td>34.00</td>
<td>1.07</td>
<td>9.00</td>
<td>40</td>
<td>21120</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>11</td>
<td>Kevlar 29-Phenolic</td>
<td>19.25</td>
<td>19.25</td>
<td>0.93</td>
<td>9.00</td>
<td>41</td>
<td>21400</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>12</td>
<td>Ti-Kevlar-Phenolic</td>
<td>22.50</td>
<td>22.38</td>
<td>0.63</td>
<td>9.05</td>
<td>41</td>
<td>21080</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>13</td>
<td>Steel-Fiberglass-Phenolic</td>
<td>35.00</td>
<td>35.00</td>
<td>0.63</td>
<td>9.00</td>
<td>42</td>
<td>21360</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>14</td>
<td>Steel-Fiberglass-Polyester</td>
<td>39.50</td>
<td>39.50</td>
<td>0.71</td>
<td>9.00</td>
<td>0</td>
<td>19040</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>15</td>
<td>Ti-Kevlar-Phenolic</td>
<td>27.50</td>
<td>27.50</td>
<td>0.73</td>
<td>9.00</td>
<td>37</td>
<td>20556</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>16</td>
<td>Kevlar 29-Phenolic</td>
<td>20.00</td>
<td>20.00</td>
<td>0.98</td>
<td>9.00</td>
<td>40</td>
<td>20665</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>17</td>
<td>Fiberglass-Polyester</td>
<td>22.00</td>
<td>22.00</td>
<td>0.71</td>
<td>9.00</td>
<td>37</td>
<td>21584</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>18</td>
<td>Titanium (6A14V)</td>
<td>35.00</td>
<td>35.00</td>
<td>0.50</td>
<td>9.00</td>
<td>37</td>
<td>21583</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>19</td>
<td>Steel-Fiberglass-Polyester</td>
<td>29.00</td>
<td>29.00</td>
<td>0.59</td>
<td>9.00</td>
<td>37</td>
<td>19750</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>20</td>
<td>Fiberglass-Phenolic</td>
<td>18.50</td>
<td>18.50</td>
<td>0.58</td>
<td>9.00</td>
<td>37</td>
<td>20060</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>21</td>
<td>Steel-Fiberglass-Phenolic</td>
<td>26.00</td>
<td>26.00</td>
<td>0.60</td>
<td>9.00</td>
<td>37</td>
<td>20570</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>22</td>
<td>Kevlar 29</td>
<td>18.00</td>
<td>18.00</td>
<td>1.50</td>
<td>9.00</td>
<td>37</td>
<td>19760</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>23</td>
<td>Kevlar 29</td>
<td>24.00</td>
<td>21.60</td>
<td>1.56</td>
<td>10.00</td>
<td>0</td>
<td>15000</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>24</td>
<td>Fiberglass-Polyester</td>
<td>21.00</td>
<td>20.86</td>
<td>0.69</td>
<td>9.06</td>
<td>67</td>
<td>20583</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>25</td>
<td>Kevlar 29-Phenolic</td>
<td>22.50</td>
<td>22.50</td>
<td>1.67</td>
<td>9.00</td>
<td>4</td>
<td>21260</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>26</td>
<td>Fiberglass-Phenolic</td>
<td>18.75</td>
<td>18.26</td>
<td>0.58</td>
<td>9.06</td>
<td>0</td>
<td>20280</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>27</td>
<td>Kevlar 29-Al Liner</td>
<td>24.75</td>
<td>24.08</td>
<td>1.5/0.063</td>
<td>9.25</td>
<td>0</td>
<td>20240</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>28</td>
<td>Fiberglass-Polyester</td>
<td>14.75</td>
<td>14.70</td>
<td>0.50</td>
<td>9.03</td>
<td>40</td>
<td>20640</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>29</td>
<td>Kevlar 29-Al Liner</td>
<td>20.25</td>
<td>18.26</td>
<td>1.1/0.063</td>
<td>9.98</td>
<td>0</td>
<td>19800</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>30</td>
<td>Kevlar 29</td>
<td>17.00</td>
<td>13.91</td>
<td>1.10</td>
<td>11.00</td>
<td>38</td>
<td>20588</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>31</td>
<td>Fiberglass-Al Liner</td>
<td>17.50</td>
<td>14.32</td>
<td>0.76</td>
<td>11.00</td>
<td>39</td>
<td>21280</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>32</td>
<td>Kevlar 29-Al Liner</td>
<td>12.00</td>
<td>10.65</td>
<td>0.76</td>
<td>10.14</td>
<td>38</td>
<td>20140</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>33</td>
<td>Kevlar 29-Al Liner</td>
<td>21.50</td>
<td>18.61</td>
<td>1.1/0.063</td>
<td>10.40</td>
<td>39</td>
<td>21300</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>34</td>
<td>Kevlar 29-Al Liner</td>
<td>18.50</td>
<td>16.00</td>
<td>0.96/0.063</td>
<td>10.40</td>
<td>38</td>
<td>19675</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>35</td>
<td>Fiberglass-Al Liner</td>
<td>23.50</td>
<td>20.53</td>
<td>0.95/0.063</td>
<td>10.30</td>
<td>39</td>
<td>20790</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>36</td>
<td>Fiberglass-Al Liner</td>
<td>19.25</td>
<td>15.75</td>
<td>0.69/0.063</td>
<td>11.00</td>
<td>43</td>
<td>20500</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>37</td>
<td>Fiberglass-Al Liner</td>
<td>15.00</td>
<td>15.00</td>
<td>0.44/0.063</td>
<td>9.00</td>
<td>0</td>
<td>21700</td>
<td>NC</td>
<td>ambient</td>
</tr>
</tbody>
</table>

TABLE 3. FAA/ARMY COMPOSITE MATERIAL GROUPS

<table>
<colgroup>
<col style="width: 5%" />
<col style="width: 6%" />
<col style="width: 17%" />
<col style="width: 7%" />
<col style="width: 8%" />
<col style="width: 10%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 7%" />
<col style="width: 10%" />
<col style="width: 7%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>G</p>
<p>r</p>
<p>o</p>
<p>u</p>
<p>p</p></td>
<td>Ring No.</td>
<td>Materials</td>
<td>Weight (lbs)</td>
<td><p>Normal-ized</p>
<p>Weight (lbs)</p></td>
<td><p>Radial Thickness</p>
<p>(in)</p></td>
<td>Axial Length (in)</td>
<td>No. of High-Speed Photos</td>
<td>Failed Speed (rpm)</td>
<td>Contained (C) or Not Contained (NC)</td>
<td>Test Temp-erature (<sup>°</sup>F)</td>
</tr>
<tr class="even">
<td>1</td>
<td>31</td>
<td>Fiberglass-Al Liner</td>
<td>17.50</td>
<td>14.32</td>
<td>0.76</td>
<td>11.00</td>
<td>39</td>
<td>21280</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>35</td>
<td>Fiberglass-Al Liner</td>
<td>23.50</td>
<td>20.53</td>
<td>0.95/0.063</td>
<td>10.30</td>
<td>39</td>
<td>20790</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>36</td>
<td>Fiberglass-Al Liner</td>
<td>19.25</td>
<td>15.75</td>
<td>0.69/0.063</td>
<td>11.00</td>
<td>43</td>
<td>20500</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>37</td>
<td>Fiberglass-Al Liner</td>
<td>15.00</td>
<td>15.00</td>
<td>0.44/0.063</td>
<td>9.00</td>
<td>0</td>
<td>21700</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>2</td>
<td>2</td>
<td>Fiberglass-Phenolic</td>
<td>48.25</td>
<td>46.84</td>
<td>1.63</td>
<td>9.27</td>
<td>0</td>
<td>20400</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>10</td>
<td>Fiberglass-Phenolic</td>
<td>34.00</td>
<td>34.00</td>
<td>1.07</td>
<td>9.00</td>
<td>40</td>
<td>21120</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>20</td>
<td>Fiberglass-Phenolic</td>
<td>18.50</td>
<td>18.50</td>
<td>0.58</td>
<td>9.00</td>
<td>37</td>
<td>20060</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>26</td>
<td>Fiberglass-Phenolic</td>
<td>18.75</td>
<td>18.26</td>
<td>0.58</td>
<td>9.06</td>
<td>0</td>
<td>20280</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>3</td>
<td>3</td>
<td>Fiberglass-Polyester</td>
<td>49.00</td>
<td>47.52</td>
<td>1.65</td>
<td>9.28</td>
<td>44</td>
<td>20945</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>9</td>
<td>Fiberglass-Polyester</td>
<td>36.75</td>
<td>36.51</td>
<td>1.18</td>
<td>9.06</td>
<td>40</td>
<td>20400</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>17</td>
<td>Fiberglass-Polyester</td>
<td>22.00</td>
<td>22.00</td>
<td>0.71</td>
<td>9.00</td>
<td>37</td>
<td>21584</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>24</td>
<td>Fiberglass-Polyester</td>
<td>21.00</td>
<td>20.86</td>
<td>0.69</td>
<td>9.06</td>
<td>67</td>
<td>20583</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>28</td>
<td>Fiberglass-Polyester</td>
<td>14.75</td>
<td>14.70</td>
<td>0.50</td>
<td>9.03</td>
<td>40</td>
<td>20640</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>4</td>
<td>22</td>
<td>Kevlar 29</td>
<td>18.00</td>
<td>18.00</td>
<td>1.50</td>
<td>9.00</td>
<td>37</td>
<td>19760</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>23</td>
<td>Kevlar 29</td>
<td>24.00</td>
<td>21.60</td>
<td>1.56</td>
<td>10.00</td>
<td>0</td>
<td>15000</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>30</td>
<td>Kevlar 29</td>
<td>17.00</td>
<td>13.91</td>
<td>1.10</td>
<td>11.00</td>
<td>38</td>
<td>20588</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>5</td>
<td>27</td>
<td>Kevlar 29-Al Liner</td>
<td>24.75</td>
<td>24.08</td>
<td>1.5/0.063</td>
<td>9.25</td>
<td>0</td>
<td>20240</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>29</td>
<td>Kevlar 29-Al Liner</td>
<td>20.25</td>
<td>18.26</td>
<td>1.1/0.063</td>
<td>9.98</td>
<td>0</td>
<td>19800</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>32</td>
<td>Kevlar 29-Al Liner</td>
<td>12.00</td>
<td>10.65</td>
<td>0.76</td>
<td>10.14</td>
<td>38</td>
<td>20140</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>33</td>
<td>Kevlar 29-Al Liner</td>
<td>21.50</td>
<td>18.61</td>
<td>1.1/0.063</td>
<td>10.40</td>
<td>39</td>
<td>21300</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>34</td>
<td>Kevlar 29-Al Liner</td>
<td>18.50</td>
<td>16.00</td>
<td>0.96/0.063</td>
<td>10.40</td>
<td>38</td>
<td>19675</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>6</td>
<td>1</td>
<td>Kevlar 29-Phenolic</td>
<td>32.00</td>
<td>28.83</td>
<td>1.62</td>
<td>9.99</td>
<td>38</td>
<td>20400</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>11</td>
<td>Kevlar 29-Phenolic</td>
<td>19.25</td>
<td>19.25</td>
<td>0.93</td>
<td>9.00</td>
<td>41</td>
<td>21400</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>16</td>
<td>Kevlar 29-Phenolic</td>
<td>20.00</td>
<td>20.00</td>
<td>0.98</td>
<td>9.00</td>
<td>40</td>
<td>20665</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>25</td>
<td>Kevlar 29-Phenolic</td>
<td>22.50</td>
<td>22.50</td>
<td>1.67</td>
<td>9.00</td>
<td>4</td>
<td>21260</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>7</td>
<td>6</td>
<td>Steel-Fiberglass-Phenolic</td>
<td>60.00</td>
<td>58.82</td>
<td>1.00 0.31/0.69</td>
<td>9.18</td>
<td>1</td>
<td>21400</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>13</td>
<td>Steel-Fiberglass-Phenolic</td>
<td>35.00</td>
<td>35.00</td>
<td>0.63 0.18/0.45</td>
<td>9.00</td>
<td>42</td>
<td>21360</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>21</td>
<td>Steel-Fiberglass-Phenolic</td>
<td>26.00</td>
<td>26.00</td>
<td>0.60 0.13/0.49</td>
<td>9.00</td>
<td>37</td>
<td>20570</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>8</td>
<td>7</td>
<td>Steel-Fiberglass-Polyester</td>
<td>65.75</td>
<td>63.90</td>
<td>1.20 0.31/.89</td>
<td>9.26</td>
<td>28</td>
<td>20700</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>14</td>
<td>Steel-Fiberglass-Polyester</td>
<td>39.50</td>
<td>39.50</td>
<td>0.71 0.19/0.52</td>
<td>9.00</td>
<td>0</td>
<td>19040</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>19</td>
<td>Steel-Fiberglass-Polyester</td>
<td>29.00</td>
<td>29.00</td>
<td>0.59 0.12/0.47</td>
<td>9.00</td>
<td>37</td>
<td>19750</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>9</td>
<td>4</td>
<td>Ti-Kevlar-Phenolic</td>
<td>37.25</td>
<td>37.13</td>
<td>1.10 0.31/0.79</td>
<td>9.03</td>
<td>42</td>
<td>20700</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>12</td>
<td>Ti-Kevlar-Phenolic</td>
<td>22.50</td>
<td>22.38</td>
<td>0.63</td>
<td>9.05</td>
<td>41</td>
<td>21080</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>15</td>
<td>Ti-Kevlar-Phenolic</td>
<td>27.50</td>
<td>27.50</td>
<td>0.73 0.25/0.48</td>
<td>9.00</td>
<td>37</td>
<td>20556</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>10</td>
<td>5</td>
<td>Titanium (6A14V)</td>
<td>44.00</td>
<td>43.95</td>
<td>0.62</td>
<td>9.01</td>
<td>1</td>
<td>20550</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>8</td>
<td>Titanium (6A14V)</td>
<td>27.25</td>
<td>26.37</td>
<td>0.40</td>
<td>9.30</td>
<td>1</td>
<td>20300</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>18</td>
<td>Titanium (6A14V)</td>
<td>35.00</td>
<td>35.00</td>
<td>0.50</td>
<td>9.00</td>
<td>37</td>
<td>21583</td>
<td>C</td>
<td>ambient</td>
</tr>
</tbody>
</table>

TABLE 4. FAA/ARMY COMPOSITE MATERIAL RINGS (CONTAINED ALL

> FRAGMENTS)

<table>
<colgroup>
<col style="width: 5%" />
<col style="width: 7%" />
<col style="width: 20%" />
<col style="width: 9%" />
<col style="width: 8%" />
<col style="width: 7%" />
<col style="width: 13%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 8%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>G</p>
<p>r</p>
<p>o</p>
<p>u</p>
<p>p</p></td>
<td>Ring No.</td>
<td>Materials</td>
<td>Normal-ized Weight (W<sub>t</sub>) (lbs)</td>
<td><p>Radial Thick-ness</p>
<p>(t) (in)</p></td>
<td><p>Failed Speed</p>
<p>(rpm)</p></td>
<td><p>Kinetic Energy (KE) x1000</p>
<p>(in.lbs)</p></td>
<td><p>KE/W<sub>t</sub> x1000</p>
<p>(in.lbs/lb)</p></td>
<td><p>KE/t</p>
<p>x1000</p>
<p>(in.lbs/in)</p></td>
<td><p>Test Temp-erature</p>
<p>( <sup>°</sup>F)</p></td>
</tr>
<tr class="even">
<td>1</td>
<td>36</td>
<td>Fiberglass-Al-Liner</td>
<td>15.75</td>
<td>0.75</td>
<td>20500</td>
<td>977</td>
<td>62</td>
<td>1303</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>2</td>
<td>2</td>
<td>Fiberglass-Phenolic</td>
<td>46.84</td>
<td>1.63</td>
<td>20400</td>
<td>968</td>
<td>21</td>
<td>594</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>10</td>
<td>Fiberglass-Phenolic</td>
<td>34.00</td>
<td>1.07</td>
<td>21120</td>
<td>1038</td>
<td>31</td>
<td>970</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>26</td>
<td>Fiberglass-Phenolic</td>
<td>18.62</td>
<td>0.58</td>
<td>20280</td>
<td>957</td>
<td>52</td>
<td>1650</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>3</td>
<td>3</td>
<td>Fiberglass-Polyester</td>
<td>47.52</td>
<td>1.65</td>
<td>20945</td>
<td>1021</td>
<td>21</td>
<td>619</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>9</td>
<td>Fiberglass-Polyester</td>
<td>36.50</td>
<td>1.18</td>
<td>20400</td>
<td>968</td>
<td>26</td>
<td>820</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>17</td>
<td>Fiberglass-Polyester</td>
<td>22.00</td>
<td>0.71</td>
<td>21584</td>
<td>1084</td>
<td>49</td>
<td>1527</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>24</td>
<td>Fiberglass-Polyester</td>
<td>20.86</td>
<td>0.69</td>
<td>20583</td>
<td>986</td>
<td>47</td>
<td>1429</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>4</td>
<td>22</td>
<td>Kevlar 29</td>
<td>18.00</td>
<td>1.50</td>
<td>19760</td>
<td>908</td>
<td>50</td>
<td>605</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>23</td>
<td>Kevlar 29</td>
<td>21.60</td>
<td>1.56</td>
<td>15000</td>
<td>523</td>
<td>24</td>
<td>335</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>5</td>
<td>27</td>
<td>Kevlar 29-Al Liner</td>
<td>24.08</td>
<td>1.53</td>
<td>20240</td>
<td>953</td>
<td>40</td>
<td>623</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>29</td>
<td>Kevlar 29-Al Liner</td>
<td>18.26</td>
<td>1.19</td>
<td>19800</td>
<td>912</td>
<td>50</td>
<td>766</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>33</td>
<td>Kevlar 29-Al Liner</td>
<td>18.61</td>
<td>1.16</td>
<td>21300</td>
<td>1055</td>
<td>57</td>
<td>910</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>34</td>
<td>Kevlar 29-Al Liner</td>
<td>16.00</td>
<td>1.02</td>
<td>19675</td>
<td>901</td>
<td>56</td>
<td>883</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>6</td>
<td>1</td>
<td>Kevlar 29 -Phenolic</td>
<td>28.83</td>
<td>1.62</td>
<td>20400</td>
<td>968</td>
<td>34</td>
<td>598</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>7</td>
<td>6</td>
<td>Steel-Fiberglass-Phenolic</td>
<td>58.82</td>
<td>1.00</td>
<td>21400</td>
<td>1065</td>
<td>18</td>
<td>1065</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>13</td>
<td>Steel-Fiberglass-Phenolic</td>
<td>35.00</td>
<td>0.63</td>
<td>21360</td>
<td>1061</td>
<td>30</td>
<td>1698</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>8</td>
<td>7</td>
<td>Steel-Fiberglass-Polyester</td>
<td>63.90</td>
<td>1.20</td>
<td>20700</td>
<td>996</td>
<td>16</td>
<td>831</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>14</td>
<td>Steel-Fiberglass-Polyester</td>
<td>39.50</td>
<td>0.71</td>
<td>19040</td>
<td>843</td>
<td>21</td>
<td>1187</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>19</td>
<td>Steel-Fiberglass-Polyester</td>
<td>29.00</td>
<td>0.57</td>
<td>19750</td>
<td>907</td>
<td>31</td>
<td>1591</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>9</td>
<td>4</td>
<td>Ti-Kevlar-Phenolic</td>
<td>37.13</td>
<td>1.10</td>
<td>20700</td>
<td>997</td>
<td>27</td>
<td>906</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>15</td>
<td>Ti-Kevlar-Phenolic</td>
<td>27.50</td>
<td>0.73</td>
<td>20556</td>
<td>983</td>
<td>36</td>
<td>1347</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>10</td>
<td>5</td>
<td>Titanium (6A14V)</td>
<td>43.95</td>
<td>0.62</td>
<td>20550</td>
<td>982</td>
<td>22</td>
<td>1584</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>18</td>
<td>Titanium (6A14V)</td>
<td>35.00</td>
<td>0.50</td>
<td>21583</td>
<td>1084</td>
<td>31</td>
<td>2168</td>
<td>ambient</td>
</tr>
</tbody>
</table>

Four dry fiberglass systems (rings 31, 35, 36, and 37), group 1, using
aluminum liners were fabricated and tested. Ring 31 did not contain all
fragments. As shown in the high-speed photographs, two fragments fully
penetrated the outer layers of the containment ring at approximately
0.75 milliseconds. Ring 37 did not contain all fragments. One disc
fragment penetrated the ring and escaped. Ring 36 contained all
fragments. Its normalized weight was 15.75 lbs. Its radial thickness was
0.75 inch. The rotor burst at 20,500 rpm generating 62 kips/lb (10^3^
in-lbs/lb) of kinetic energy per normalized weight (KE~w~) and 1,303
kips/in of kinetic energy per thickness (KE~t~). These values
represented the threshold configuration of aluminum lined fiberglass
system. Three fragments were embedded in the inner layers of the
containment ring. Ring 35 was heavier and thicker. It did not, however,
contain all fragments. The rotor burst at 20,790 rpm producing 1,005
kips of total kinetic energy. One disc fragment penetrated the ring and
escaped. In both rings, 35 and 36, their weight and thickness were close
to the design threshold and the overspeed burst increases the kinetic
energy of the rotor fragments, which would be sufficient to penetrate
the containment system. Additionally, containment ring performance may
not be directly proportional to the ring thickness and the number of ply
due to variations in fabrication technique. Figure 14 shows the posttest
pictures of rings 31, 35, 36, and

37\. Figure 15 shows the failure event of rings 31 and 36 recorded by
the Cordin high-speed camera. Time at burst (t~b~), the time when the
trip circuit was hit by the blades momentarily after burst, was set at
zero. Initial impact time was t~i~, the time when the disc surface first
impacted the inner surface of the ring. The time when one or all
fragments just completely penetrated and escaped the containment ring
outer surface was t~e~. The duration of complete penetration was the
period between t~i~ and t~e~. Last recorded event shows the last picture
recorded by the high speed camera at time t~l~.

Figure 16 shows the threshold containment and a typical residual kinetic
energy. The residual energy of the fragment leaving ring 31 was 13.3
kips. It was derived from the estimated penetrating duration taken from
the high-speed film. Based on this approximation, the uncontained
fragment was leaving ring 31 at the speed of approximately 1,690 inches
per second, an equivalence of 96 miles per hour.

![](media/image15.emf){width="6.497916666666667in"
height="5.470138888888889in"}

FIGURE 14. POSTTEST PICTURES OF RINGS 31, 35, 36, AND 37

![](media/image16.emf){width="5.897916666666666in"
height="6.961805555555555in"}

FIGURE 15. FAILURE EVENT OF RINGS 31 AND 36

![](media/image17.emf){width="5.709722222222222in"
height="4.268055555555556in"}

<table>
<colgroup>
<col style="width: 4%" />
<col style="width: 0%" />
<col style="width: 6%" />
<col style="width: 0%" />
<col style="width: 16%" />
<col style="width: 0%" />
<col style="width: 7%" />
<col style="width: 0%" />
<col style="width: 9%" />
<col style="width: 0%" />
<col style="width: 10%" />
<col style="width: 0%" />
<col style="width: 8%" />
<col style="width: 0%" />
<col style="width: 7%" />
<col style="width: 0%" />
<col style="width: 7%" />
<col style="width: 0%" />
<col style="width: 9%" />
<col style="width: 0%" />
<col style="width: 10%" />
</colgroup>
<tbody>
<tr class="odd">
<td colspan="2"><p>G</p>
<p>r</p>
<p>o</p>
<p>u</p>
<p>p</p></td>
<td colspan="2">Ring No.</td>
<td colspan="2">Materials</td>
<td colspan="2"><p>Weight</p>
<p>(lbs)</p></td>
<td colspan="2"><p>Normal-ized</p>
<p>Weight</p>
<p>(lbs)</p></td>
<td colspan="2"><p>Radial Thickness</p>
<p>(in)</p></td>
<td colspan="2"><p>Axial Length</p>
<p>(in)</p></td>
<td colspan="2">No. of High-Speed Photos</td>
<td colspan="2">Failed Speed (rpm)</td>
<td colspan="2"><p>Contained (C) or Not Contained</p>
<p>(NC)</p></td>
<td><p>Test Temp-erature</p>
<p>(<sup>°</sup>F)</p></td>
</tr>
<tr class="even">
<td></td>
<td colspan="2">31</td>
<td colspan="2">Fiberglass-Al liner</td>
<td colspan="2">17.50</td>
<td colspan="2">14.32</td>
<td colspan="2">0.76</td>
<td colspan="2">11.00</td>
<td colspan="2">39</td>
<td colspan="2">21280</td>
<td colspan="2">NC</td>
<td colspan="2">ambient</td>
</tr>
<tr class="odd">
<td>1</td>
<td colspan="2">35</td>
<td colspan="2">Fiberglass-Al liner</td>
<td colspan="2">23.50</td>
<td colspan="2">20.53</td>
<td colspan="2">0.95/0.063</td>
<td colspan="2">10.30</td>
<td colspan="2">39</td>
<td colspan="2">20790</td>
<td colspan="2">NC</td>
<td colspan="2">ambient</td>
</tr>
<tr class="even">
<td></td>
<td colspan="2">36</td>
<td colspan="2">Fiberglass- Al liner</td>
<td colspan="2">19.25</td>
<td colspan="2">15.75</td>
<td colspan="2">0.69/0.063</td>
<td colspan="2">11.00</td>
<td colspan="2">43</td>
<td colspan="2">20500</td>
<td colspan="2">C</td>
<td colspan="2">ambient</td>
</tr>
<tr class="odd">
<td></td>
<td colspan="2">37</td>
<td colspan="2">Fiberglass-Al liner</td>
<td colspan="2">15.00</td>
<td colspan="2">15.00</td>
<td colspan="2">0.44/.0063</td>
<td colspan="2">9.00</td>
<td colspan="2">0</td>
<td colspan="2">21700</td>
<td colspan="2">NC</td>
<td colspan="2">ambient</td>
</tr>
</tbody>
</table>

FIGURE 16. GROUP 1FIBERGLASS-ALUMINUM

Group 2, fiberglass impregnated with phenolic resin, had four systems
(rings 2, 10, 20, and 26). Rings 2, 10, and 26 contained all fragments.
Normalized weight and thickness of ring 2 were 46.84 lbs and 1.63
inches, ring 10 were 34.00 lbs and 1.07 inches, and ring 26 were 18.62
lbs and 0.58 inch respectively. KE~w~ and KE~t~ of ring 2 were 21
kips/lb and 594 kips/in, ring 10 were 31 kips/lb and 970 kips/in, and
ring 26 were 52 kips/lb and 1,650 kips/in respectively. System 26
provided threshold values for this group. One disc fragment penetrated
ring 20 and escaped. Rings 10 and 2 inner fiberglass layers were
severely damaged. Two-thirds of the outer most layers were not
significantly distorted. Figure 17 shows the posttest pictures of rings
2, 10, and 20. Figure 18 shows the failure event of ring 10. Figure 19
shows the contained area and threshold containment of group 2.

FIGURE 17. POSTTEST PICTURES OF RINGS 2, 10, AND
20![](media/image18.emf){width="5.320138888888889in" height="7.98125in"}

![](media/image19.emf){width="6.493055555555555in"
height="4.009722222222222in"}FIGURE 18. FAILURE EVENT OF RING 10

Group 3, fiberglass impregnated with polyester resin, had five systems
(rings 3, 9, 17, 24, and 28). Rings 3, 9, 17, and 24 contained all
fragments. No significant damage on the outer most layers of these rings
was recorded. Normalized weight and thickness of ring 3 were 47.52 lbs
and 1.65 inches, ring 9 were 36.50 lbs and 1.18 inches, ring 17 were
22.00 lbs and 0.71 inch, and ring 24 were 20.86 lbs and 0.69 inch
respectively. KE~w~ and KE~t~ of ring 3 were 21 kips/lb and 619 kips/in,
ring 9 were 26 kips/lb and 820 kips/in, ring 17 were 49 kips/lb and
1,527 kips/in, and ring 24 were 47 kips/lb and 1,429 kips/in
respectively. System 24 represented the threshold configuration. System
17, however, provided higher energy absorbed per unit weight, and it was
selected for ranking. One disc fragment penetrated ring 28 and escaped.
Figure 20 shows the posttest pictures of rings 3, 9, and 17. Figures 21
and 22 show the failure event of ring 3, 9, 17, and 24. Figure 23 shows
the failure event and posttest pictures of ring 28. Figure 24 shows the
contained area of group 3. The residual energy of the fragment leaving
ring 28 at the speed of 317 inches per second or 18 miles per hour was
approximately 467 in-lbs.

![](media/image20.emf){width="4.882638888888889in"
height="3.7284722222222224in"}

<table>
<colgroup>
<col style="width: 4%" />
<col style="width: 6%" />
<col style="width: 16%" />
<col style="width: 8%" />
<col style="width: 9%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 10%" />
<col style="width: 9%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>G</p>
<p>r</p>
<p>o</p>
<p>u</p>
<p>p</p></td>
<td>Ring No.</td>
<td>Materials</td>
<td><p>Weight</p>
<p>(lbs)</p></td>
<td><p>Normal-ized</p>
<p>Weight</p>
<p>(lbs)</p></td>
<td><p>Radial Thick-ness</p>
<p>(in)</p></td>
<td><p>Axial Length</p>
<p>(in)</p></td>
<td>No. of High-Speed Photos</td>
<td>Failed Speed (rpm)</td>
<td><p>Contained (C) or Not Contained</p>
<p>(NC)</p></td>
<td><p>Test Temp-erature</p>
<p>(<sup>°</sup>F)</p></td>
</tr>
<tr class="even">
<td></td>
<td>2</td>
<td>Fiberglass-phenolic</td>
<td>48.25</td>
<td>46.84</td>
<td>1.63</td>
<td>9.27</td>
<td>0</td>
<td>20400</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>2</td>
<td>10</td>
<td>Fiberglass-phenolic</td>
<td>34.00</td>
<td>34.00</td>
<td>1.07</td>
<td>9.00</td>
<td>40</td>
<td>21120</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>20</td>
<td>Fiberglass-phenolic</td>
<td>18.50</td>
<td>18.50</td>
<td>0.58</td>
<td>9.00</td>
<td>37</td>
<td>20060</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>26</td>
<td>Fiberglass-phenolic</td>
<td>18.75</td>
<td>18.26</td>
<td>0.58</td>
<td>9.06</td>
<td>0</td>
<td>20280</td>
<td>C</td>
<td>ambient</td>
</tr>
</tbody>
</table>

FIGURE 19. GROUP 2FIBERGLASS-PHENOLIC

![](media/image21.emf){width="4.551388888888889in"
height="6.930555555555555in"}

FIGURE 20. POSTTEST PICTURES OF RINGS 3, 9, AND 17

![](media/image22.emf){width="4.922916666666667in"
height="5.9527777777777775in"}

Figure 21. FAILURE EVENT OF RINGS 3 AND 9

![](media/image23.emf){width="5.054861111111111in"
height="5.876388888888889in"}

FIGURE 22 FIALURE EVENT OF RINGS 17 AND 24

![](media/image24.emf){width="6.499305555555556in"
height="6.4534722222222225in"}FIGURE 23. FAILURE EVENT AND POSTTEST
PICTURES OF RING 28

![](media/image25.emf){width="5.927083333333333in"
height="4.614583333333333in"}

<table>
<colgroup>
<col style="width: 4%" />
<col style="width: 6%" />
<col style="width: 17%" />
<col style="width: 8%" />
<col style="width: 9%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 10%" />
<col style="width: 9%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>G</p>
<p>r</p>
<p>o</p>
<p>u</p>
<p>p</p></td>
<td>Ring No.</td>
<td>Materials</td>
<td><p>Weight</p>
<p>(lbs)</p></td>
<td><p>Normal-ized</p>
<p>Weight</p>
<p>(lbs)</p></td>
<td><p>Radial Thick-ness</p>
<p>(in)</p></td>
<td><p>Axial Length</p>
<p>(in)</p></td>
<td>No. of High-Speed Photos</td>
<td>Failed Speed (rpm)</td>
<td><p>Contained (C) or Not Contained</p>
<p>(NC)</p></td>
<td><p>Test Temp-erature</p>
<p>(<sup>°</sup>F)</p></td>
</tr>
<tr class="even">
<td></td>
<td>3</td>
<td>Fiberglass-polyester</td>
<td>49.00</td>
<td>47.52</td>
<td>1.65</td>
<td>9.28</td>
<td>44</td>
<td>20945</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>9</td>
<td>Fiberglass-polyester</td>
<td>36.75</td>
<td>36.51</td>
<td>1.18</td>
<td>9.06</td>
<td>40</td>
<td>20400</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>3</td>
<td>17</td>
<td>Fiberglass-polyester</td>
<td>22.00</td>
<td>22.00</td>
<td>0.71</td>
<td>9.00</td>
<td>37</td>
<td>21584</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>24</td>
<td>Fiberglass-polyester</td>
<td>21.00</td>
<td>20.86</td>
<td>0.69</td>
<td>9.06</td>
<td>67</td>
<td>20583</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>28</td>
<td>Fiberglass-polyester</td>
<td>14.75</td>
<td>14.70</td>
<td>0.50</td>
<td>9.03</td>
<td>40</td>
<td>20640</td>
<td>NC</td>
<td>ambient</td>
</tr>
</tbody>
</table>

FIGURE 24. GROUP 3FIBERGLASS-POLYESTER

Groups 4 and 5 had Kevlar 29 systems. The systems in group 4 did not
have aluminum liners. Rings 22 and 23 contained all fragments.
Normalized weight and thickness of ring 22 were 18.00 lbs and 1.50
inches and ring 23 were 21.60 lbs and 1.56 inches respectively. KE~w~
and KE~t~ of ring 22 were 50 kips/lb and 605 kips/in and ring 23 were 24
kips/lb and 335 kips/in respectively. System 22 therefore represented
the threshold configuration for this group. One disc fragment penetrated
ring 30 and escaped. Figure 25 shows the posttest pictures of rings 22
and 30. Figure 26 shows the failure event of ring 30.

![](media/image26.emf){width="4.604861111111111in"
height="7.207638888888889in"}

FIGURE 25. POSTTEST PICTURES OF RINGS 22 AND 30

![](media/image27.emf){width="5.676388888888889in"
height="3.2423611111111112in"}

FIGURE 26. FAILURE EVENT OF RING 30

Figure 27 shows the contained area of group 4. The uncontained fragment
was leaving ring 30 at the speed of approximately 399 inches per second
or 23 miles per hour. Its residual energy was approximately 740 in-lbs.

Group 5 had four aluminum lined Kevlar systems (rings 27, 29, 33, and
34) which contained all fragments. Normalized weight and thickness of
ring 27 were 24.08 lbs and 1.53 inches, ring 29 were 18.26 lbs and 1.19
inches, ring 33 were 18.61 lbs and 1.16 inches, and ring 34 were 16.00
lbs and 1.02 inches respectively. KE~w~ and KE~t~ of ring 27 were 40
kips/lb and 623 kips/in, ring 29 were 50 kips/lb and 766 kips/in, ring
33 were 57 kips/lb and 910 kips/in, and ring 34 were 56 kips/lb and 883
kips/in respectively. System 33 had the threshold values. One disc
fragment penetrated rings 32 and 33. Figure 28 shows the posttest
picture of rings 29, 32, 33, and 34. Figures 29 and 30 show the failure
event of rings 32, 33, and 34.

![](media/image28.emf){width="6.010416666666667in"
height="4.614583333333333in"}

<table>
<colgroup>
<col style="width: 4%" />
<col style="width: 6%" />
<col style="width: 10%" />
<col style="width: 8%" />
<col style="width: 10%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 11%" />
<col style="width: 11%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>G</p>
<p>r</p>
<p>o</p>
<p>u</p>
<p>p</p></td>
<td>Ring No.</td>
<td>Materials</td>
<td><p>Weight</p>
<p>(lbs)</p></td>
<td><p>Normal-ized</p>
<p>Weight</p>
<p>(lbs)</p></td>
<td><p>Radial Thick-ness</p>
<p>(in)</p></td>
<td><p>Axial Length</p>
<p>(in)</p></td>
<td>No. of High-Speed Photos</td>
<td>Failed Speed (rpm)</td>
<td><p>Contained (C) or Not Contained</p>
<p>(NC)</p></td>
<td><p>Test</p>
<p>Temperature</p>
<p>(<sup>°</sup>F)</p></td>
</tr>
<tr class="even">
<td></td>
<td>22</td>
<td>Kevlar 29</td>
<td>18.00</td>
<td>18.00</td>
<td>1.50</td>
<td>9.00</td>
<td>37</td>
<td>19760</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>4</td>
<td>23</td>
<td>Kevlar 29</td>
<td>24.00</td>
<td>21.60</td>
<td>1.56</td>
<td>10.00</td>
<td>0</td>
<td>15000</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>30</td>
<td>Kevlar 29</td>
<td>17.00</td>
<td>13.91</td>
<td>1.10</td>
<td>11.00</td>
<td>38</td>
<td>20588</td>
<td>NC</td>
<td>ambient</td>
</tr>
</tbody>
</table>

FIGURE 27. GROUP 4DRY KEVLAR 29

![](media/image29.emf){width="5.490277777777778in"
height="4.506944444444445in"}

FIGURE 28. POSTTEST PICTURES OF RINGS 29, 32, 33, AND 34

![](media/image30.emf){width="4.821527777777778in"
height="7.292361111111111in"}

FIGURE 29. FAILURE EVENT OF RING 32

#### ![](media/image31.emf){width="5.820833333333334in" height="7.2125in"}

FIGURE 30. FAILURE EVENT OF RINGS 33 AND 34

Figure 31 shows the uncontained area. The uncontained fragment of ring
32 had the residual energy of 2,981 in-lbs. The uncontained fragment
left ring 32 at the speed of approximately 800 inches per second or 44
miles per hour.

Group 6 had four Kevlar systems impregnated with phenolic resin (rings
1, 11, 16, and 25). Only ring 1 contained all rotor fragments.
Normalized weight and thickness of ring 1 were 28.83 lbs and 1.62
inches. KE~w~ and KE~t~ of ring 1 were 34 kips/lb and 598 kips/in. These
were the threshold values for this group. Three disc fragments
penetrated and escaped ring 11. Two penetrated and escaped ring 16. One
penetrated and escaped ring 25. Figure 32 shows the pictures of rings 1,
11, and 16. Figure 33 shows the failure event of rings 1 and 11. Figure
34 show the failure event of rings 16 and 25.

> ![](media/image32.emf){width="5.6618055555555555in"
> height="4.351388888888889in"}

<table>
<colgroup>
<col style="width: 4%" />
<col style="width: 6%" />
<col style="width: 16%" />
<col style="width: 8%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 7%" />
<col style="width: 10%" />
<col style="width: 10%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>G</p>
<p>r</p>
<p>o</p>
<p>u</p>
<p>p</p></td>
<td>Ring No.</td>
<td>Materials</td>
<td><p>Weight</p>
<p>(lbs)</p></td>
<td><p>Normal-ized</p>
<p>Weight</p>
<p>(lbs)</p></td>
<td><p>Radial Thick-ness</p>
<p>(in)</p></td>
<td><p>Axial Length</p>
<p>(in)</p></td>
<td>No. of High-Speed Photos</td>
<td>Failed Speed (rpm)</td>
<td><p>Contained (C) or Not Contained</p>
<p>(NC)</p></td>
<td><p>Test Temp-erature</p>
<p>(<sup>°</sup>F)</p></td>
</tr>
<tr class="even">
<td></td>
<td>27</td>
<td>Kevlar 29 - Al liner</td>
<td>24.75</td>
<td>24.08</td>
<td>1.5/.063</td>
<td>9.25</td>
<td>0</td>
<td>20240</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>29</td>
<td>Kevlar 29 - Al liner</td>
<td>20.25</td>
<td>18.26</td>
<td>1.1/.063</td>
<td>9.98</td>
<td>0</td>
<td>19800</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td>5</td>
<td>32</td>
<td>Kevlar 29 - Al liner</td>
<td>12.00</td>
<td>10.65</td>
<td>0.76</td>
<td>10.14</td>
<td>38</td>
<td>20140</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>33</td>
<td>Kevlar 29 - Al liner</td>
<td>21.50</td>
<td>18.61</td>
<td>1.1/.063</td>
<td>10.40</td>
<td>39</td>
<td>21300</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>34</td>
<td>Kevlar 29 - Al liner</td>
<td>18.50</td>
<td>16.00</td>
<td>0.96/0063</td>
<td>10.40</td>
<td>38</td>
<td>19675</td>
<td>C</td>
<td>ambient</td>
</tr>
</tbody>
</table>

FIGURE 31. GROUP 5DRY KEVLAR 29-ALUMINUM

![](media/image33.emf){width="5.695833333333334in"
height="6.408333333333333in"}

Figure 32. POSTTEST PICTURES OF RINGS 1, 11, AND 16

![](media/image34.emf){width="6.0625in" height="7.342361111111111in"}

FIGURE 33. FAILURE EVENT OF RINGS 1 AND 11

![](media/image35.emf){width="6.499305555555556in"
height="7.870833333333334in"}FIGURE 34. FAILURE EVENT OF RINGS 16 AND 25

Figure 35 shows that the uncontained fragment of ring 11 had the
residual energy of 15.5 kips. The fragment was leaving ring 11 at the
speed of approximately 1,824 inches per second or 104 miles per hour.

Group 7 had three steel and fiberglass composite systems (rings 6, 13,
and 21). Fiberglass was also impregnated with phenolic resin. Rings 6
and 13 contained all rotor fragments. Steel layer thicknesses of rings 6
and 13 were 0.31 and 0.18 inch respectively. Normalized weight and
thickness of ring 6 were 58.82 lbs and 1.00 inch and ring 13 were 35.00
lbs and 0.63 inch. KE~w~ and KE~t~ of ring 6 were 18 kips/lb and 1,065
kips/in and ring 13 were 30 kips/lb and 1,698 kips/in. System 13
represented the threshold configuration for this group. One disc
fragment penetrated and escaped ring 21. Figure 36 shows the posttest
event of rings 6, 13, and 21. Figure 37 shows the failure event of ring
13 and 21.

![](media/image36.emf){width="5.6618055555555555in"
height="4.351388888888889in"}

<table>
<colgroup>
<col style="width: 4%" />
<col style="width: 6%" />
<col style="width: 17%" />
<col style="width: 8%" />
<col style="width: 9%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 10%" />
<col style="width: 9%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>G</p>
<p>r</p>
<p>o</p>
<p>u</p>
<p>p</p></td>
<td>Ring No.</td>
<td>Materials</td>
<td><p>Weight</p>
<p>(lbs)</p></td>
<td><p>Normal-ized</p>
<p>Weight</p>
<p>(lbs)</p></td>
<td><p>Radial Thick-ness</p>
<p>(in)</p></td>
<td><p>Axial Length</p>
<p>(in)</p></td>
<td>No. of High-Speed Photos</td>
<td>Failed Speed (rpm)</td>
<td><p>Contained (C) or Not Contained</p>
<p>(NC)</p></td>
<td><p>Test Temp-erature</p>
<p>(<sup>°</sup>F)</p></td>
</tr>
<tr class="even">
<td></td>
<td>1</td>
<td>Kevlar 29 - phenolic</td>
<td>32.00</td>
<td>28.83</td>
<td>1.62</td>
<td>9.99</td>
<td>38</td>
<td>20400</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>6</td>
<td>11</td>
<td>Kevlar 29 - phenolic</td>
<td>19.25</td>
<td>19.25</td>
<td>0.93</td>
<td>9.00</td>
<td>41</td>
<td>21400</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>16</td>
<td>Kevlar 29 - phenolic</td>
<td>20.00</td>
<td>20.00</td>
<td>0.98</td>
<td>9.00</td>
<td>40</td>
<td>20665</td>
<td>NC</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td></td>
<td>25</td>
<td>Kevlar 29 - phenolic</td>
<td>22.50</td>
<td>22.50</td>
<td>1.67</td>
<td>9.00</td>
<td>4</td>
<td>21260</td>
<td>NC</td>
<td>ambient</td>
</tr>
</tbody>
</table>

FIGURE 35. GROUP 6KEVLAR 29-PHENOLIC

![](media/image37.emf){width="5.70625in" height="7.930555555555555in"}

FIGURE 36. POSTTEST PICTURES OF RINGS 6, 13, AND 21

![](media/image38.emf){width="6.499305555555556in"
height="7.413194444444445in"}FIGURE 37. FAILURE EVENT OF RINGS 13 AND 21

Figure 38 shows the uncontained fragment leaving ring 21 with the
residual energy of 284 in-lbs at the speed of 247 inches per second or
14 miles per hour.

All systems (rings 7, 14, and 19) in group 8 contained all rotor
fragments. Steel layer thickness of rings 7, 14, and 19 were 0.31, 0.19,
and 0.12 inch respectively. Normalized weight and thickness of ring 7
were 63.90 lbs and 1.20 inches, ring 14 were 39.50 lbs and 0.71 inch,
and ring 19 were 29.00 lbs and 0.57 inch respectively. KE~w~ and KE~t~
of ring 7 were 16 kips/lb and 831 kips/in, ring 14 were 21 kips/lb and
1,187 kips/in, and ring 19 were 31 kips/lb and 1.591 kips/in
respectively. No system represented the threshold configuration. System
7 was, however, selected for ranking due to its higher energy absorbed
per unit weight. Minimum damage was done on these systems. Figure 39
shows the posttest pictures of rings 7, 14, and 19. Figure 40 shows the
failure event of ring 7 and 19. Figure 41 shows the contained area
without the threshold value.

![](media/image39.emf){width="6.010416666666667in"
height="4.614583333333333in"}

<table style="width:100%;">
<colgroup>
<col style="width: 4%" />
<col style="width: 5%" />
<col style="width: 19%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 9%" />
<col style="width: 7%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 10%" />
<col style="width: 8%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>G</p>
<p>r</p>
<p>o</p>
<p>u</p>
<p>p</p></td>
<td>Ring No.</td>
<td>Materials</td>
<td><p>Weight</p>
<p>(lbs)</p></td>
<td><p>Normal-ized</p>
<p>Weight</p>
<p>(lbs)</p></td>
<td>Radial Thick-ness (in)</td>
<td><p>Axial Length</p>
<p>(in)</p></td>
<td>No. of High-Speed Photos</td>
<td>Failed Speed (rpm)</td>
<td>Contained (C) or Not Contained (NC)</td>
<td><p>Test Temp-erature</p>
<p>(<sup>°</sup>F)</p></td>
</tr>
<tr class="even">
<td></td>
<td>6</td>
<td>Steel-fiberglass-phenolic</td>
<td>60.00</td>
<td>58.82</td>
<td>1.00 0.31/0.69</td>
<td>9.18</td>
<td>1</td>
<td>21400</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>7</td>
<td>13</td>
<td>Steel-fiberglass-phenolic</td>
<td>35.00</td>
<td>35.00</td>
<td>0.63 0.18/0.45</td>
<td>9.00</td>
<td>42</td>
<td>21360</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>21</td>
<td>Steel-fiberglass-phenolic</td>
<td>26.00</td>
<td>26.00</td>
<td>0.60 0.13/0.49</td>
<td>9.00</td>
<td>37</td>
<td>20570</td>
<td>NC</td>
<td>ambient</td>
</tr>
</tbody>
</table>

FIGURE 38. GROUP 7STEEL-FIBERGLASS-PHENOLIC

![](media/image40.emf){width="5.790972222222222in"
height="6.477083333333334in"}

FIGURE 39. POSTTEST PICTURES OF RINGS 7, 14, AND 19

![](media/image41.emf){width="6.493055555555555in"
height="8.195833333333333in"}FIGURE 40. FAILURE EVENT OF RINGS 7 AND 19

![](media/image42.emf){width="6.010416666666667in"
height="4.614583333333333in"}

<table style="width:100%;">
<colgroup>
<col style="width: 4%" />
<col style="width: 7%" />
<col style="width: 16%" />
<col style="width: 8%" />
<col style="width: 9%" />
<col style="width: 10%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 7%" />
<col style="width: 10%" />
<col style="width: 9%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>G</p>
<p>r</p>
<p>o</p>
<p>u</p>
<p>p</p></td>
<td>Ring No.</td>
<td>Materials</td>
<td><p>Weight</p>
<p>(lbs)</p></td>
<td><p>Normal-ized</p>
<p>Weight</p>
<p>(lbs)</p></td>
<td>Radial Thickness (in)</td>
<td><p>Axial Length</p>
<p>(in)</p></td>
<td>No. of High-Speed Photos</td>
<td>Failed Speed (rpm)</td>
<td><p>Contained (C) or Not Contained</p>
<p>(NC)</p></td>
<td><p>Test Temp-erature</p>
<p>(<sup>°</sup>F)</p></td>
</tr>
<tr class="even">
<td></td>
<td>7</td>
<td>Steel-fiberglass-polyester</td>
<td>65.75</td>
<td>63.90</td>
<td>1.20 0.31/0.89</td>
<td>9.26</td>
<td>28</td>
<td>20700</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>8</td>
<td>14</td>
<td>Steel-fiberglass-polyester</td>
<td>39.50</td>
<td>39.50</td>
<td>0.71 0.19/0.52</td>
<td>9.00</td>
<td>0</td>
<td>19040</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>19</td>
<td>Steel-fiberglass-polyester</td>
<td>29.00</td>
<td>29.00</td>
<td>0.59 0.12/0.47</td>
<td>9.00</td>
<td>37</td>
<td>19750</td>
<td>C</td>
<td>ambient</td>
</tr>
</tbody>
</table>

FIGURE 41. GROUP 8STEEL-FIBERGLASS-POLYESTER

Group 9 had three titanium-Kevlar composite systems (rings 4, 12, and
15). Kevlar was also impregnated with phenolic resin. Rings 4 and 15
contained all fragments. Titanium layer thickness of rings 4 and 15 was
0.31 and 0.25 inch. Normalized weight and thickness of ring 4 were 37.13
lbs and 1.10 inches and ring 15 were 27.50 lbs and 0.73 inch
respectively. KE~w~ and KE~t~ of ring 4 were 27 kips/lb and 906 kips/in
and ring 15 were 36 kips/lb and 1,347 kips/in respectively. System 15
gave threshold values. One fragment penetrated the titanium layer and
punched a hole in the Kevlar ring. System 4 was selected for ranking due
to its higher energy absorbed per unit weight. Two disc fragments
penetrated and escaped ring 15. Figure 42 shows the posttest pictures of
ring 4, 12, and 15. Figures 43 and 44 show the failure event of rings 4,
12, and 15.

Figure 45 shows the typical residual energy of the uncontained fragment
of this group. The fragment was leaving ring 12 with the energy of 9.5
kips at the speed of approximately 1,432 inches per seconds or an
equivalence of 81 miles per hour.

The last group, group 10, consisted of three titanium systems (rings 5,
8, and 18). Rings 5 and 18 contained all rotor fragments. Minimum damage
was recorded on these rings. Normalized weight and thickness of ring 5
were 43.95 lbs and 0.62 inch and ring 18 were 35.00 lbs and 0.50 inch.
KE~w~ and KE~t~ of ring 5 were 22 kips/lb and 1,584 kips/in and ring 18
were 31 kips/lb and 2,168 kips/in. System 18 gave threshold values for
this group and provided highest energy absorbed per unit weight. One
disc fragment penetrated and escaped ring 8. Figure 46 shows the
posttest pictures of rings 5, 8, and 18. Figure 47 shows the failure
event of ring 18.

Figure 48 shows the contained area of this group.

Figure 49 shows the containment ring weight versus penetrating duration
for uncontained systems. For a given penetrating duration, dry Kevlar
performed better than Kevlar-phenolic system based on its weight. There
are not sufficient data on other uncontained systems to make a
parametric comparison.

Similarly, figure 50 confirms the observation made in figure 49 that dry
Kevlar also performed better than the Kevlar-phenolic system based on
its thickness.

#### ![](media/image43.emf){width="6.493055555555555in" height="7.426388888888889in"}

FIGURE 42. POSTTEST PICTURES OF RINGS 4, 12, AND 15

#### ![](media/image44.emf){width="6.057638888888889in" height="7.925694444444445in"}

FIGURE 43. FAILURE EVENT OF RINGS 4 AND 12

![](media/image45.emf){width="4.976388888888889in"
height="7.4215277777777775in"}

FIGURE 44. FAILURE EVENT OF RING 15

![](media/image46.emf){width="6.010416666666667in"
height="4.614583333333333in"}

<table>
<colgroup>
<col style="width: 4%" />
<col style="width: 6%" />
<col style="width: 16%" />
<col style="width: 8%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 10%" />
<col style="width: 9%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>G</p>
<p>r</p>
<p>o</p>
<p>u</p>
<p>p</p></td>
<td>Ring No.</td>
<td>Materials</td>
<td><p>Weight</p>
<p>(lbs)</p></td>
<td><p>Normal-ized</p>
<p>Weight</p>
<p>(lbs)</p></td>
<td>Radial Thick-ness (in)</td>
<td><p>Axial Length</p>
<p>(in)</p></td>
<td>No. of High-Speed Photos</td>
<td>Failed Speed (rpm)</td>
<td><p>Contained (C) or Not Contained</p>
<p>(NC)</p></td>
<td><p>Test Temp-erature</p>
<p>(<sup>°</sup>F)</p></td>
</tr>
<tr class="even">
<td></td>
<td>4</td>
<td>Ti-kevlar-phenolic</td>
<td>37.25</td>
<td>37.13</td>
<td>1.10 0.31/0.79</td>
<td>9.03</td>
<td>42</td>
<td>20700</td>
<td>C</td>
<td>ambient</td>
</tr>
<tr class="odd">
<td>9</td>
<td>12</td>
<td>Ti-kevlar-phenolic</td>
<td>22.50</td>
<td>22.38</td>
<td>0.63</td>
<td>9.05</td>
<td>41</td>
<td>21080</td>
<td>N</td>
<td>ambient</td>
</tr>
<tr class="even">
<td></td>
<td>15</td>
<td>Ti-kevlar-phenolic</td>
<td>27.50</td>
<td>27.50</td>
<td>0.73 0.25/0.48</td>
<td>9.00</td>
<td>37</td>
<td>20556</td>
<td>C</td>
<td>ambient</td>
</tr>
</tbody>
</table>

FIGURE 45. GROUP 9TITANIUM-DRY KEVLAR-PHENOLIC

![](media/image47.emf){width="6.499305555555556in"
height="7.618055555555555in"}

FIGURE 46. POSTTEST PICTURES OF RINGS 5, 8, AND 18

![](media/image48.emf){width="5.475in" height="7.627777777777778in"}

FIGURE 47. FAILURE EVENT OF RING 18

![](media/image49.emf){width="6.010416666666667in"
height="4.614583333333333in"}

<table>
<colgroup>
<col style="width: 5%" />
<col style="width: 6%" />
<col style="width: 16%" />
<col style="width: 8%" />
<col style="width: 9%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 0%" />
<col style="width: 9%" />
<col style="width: 0%" />
<col style="width: 7%" />
<col style="width: 0%" />
<col style="width: 10%" />
<col style="width: 0%" />
<col style="width: 9%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>G</p>
<p>r</p>
<p>o</p>
<p>u</p>
<p>p</p></td>
<td>Ring No.</td>
<td>Materials</td>
<td><p>Weight</p>
<p>(lbs)</p></td>
<td><p>Normal-ized</p>
<p>Weight</p>
<p>(lbs)</p></td>
<td><p>Radial Thick-ness</p>
<p>(in)</p></td>
<td colspan="2"><p>Axial Length</p>
<p>(in)</p></td>
<td colspan="2">No. of High-Speed Photos</td>
<td colspan="2">Failed Speed (rpm)</td>
<td colspan="2"><p>Contained (C) or Not Contained</p>
<p>(NC)</p></td>
<td><p>Test Temp-erature</p>
<p>(<sup>°</sup>F)</p></td>
</tr>
<tr class="even">
<td></td>
<td>5</td>
<td>Titanium (6A14V)</td>
<td>44.00</td>
<td>43.95</td>
<td>0.62</td>
<td>9.01</td>
<td colspan="2">1</td>
<td colspan="2">20550</td>
<td colspan="2">C</td>
<td colspan="2">ambient</td>
</tr>
<tr class="odd">
<td>10</td>
<td>8</td>
<td>Titanium (6A14V)</td>
<td>27.25</td>
<td>26.37</td>
<td>0.40</td>
<td>9.30</td>
<td colspan="2">1</td>
<td colspan="2">20300</td>
<td colspan="2">NC</td>
<td colspan="2">ambient</td>
</tr>
<tr class="even">
<td></td>
<td>18</td>
<td>Titanium (6A14V)</td>
<td>35.00</td>
<td>35.00</td>
<td>0.50</td>
<td>9.00</td>
<td colspan="2">37</td>
<td colspan="2">21583</td>
<td colspan="2">C</td>
<td colspan="2">ambient</td>
</tr>
</tbody>
</table>

FIGURE 48. GROUP 10TITANIUM

> ![](media/image50.emf){width="5.8125in" height="5.145833333333333in"}

## Systems

> Ring 12: Titanium-Kevlar-Phenolic
>
> Ring 21: Steel-Fiberglass-Polyester
>
> Rings 11, 16, and 25: Kevlar-Phenolic
>
> Ring 31: Fiberglass-Aluminum
>
> Ring 28: Fiberglass Polyester
>
> Rings 32 and 30: Kevlar-Aluminum

FIGURE 49. WEIGHT INCREASE VERSUS PENETRATING DURATION

> ![](media/image51.emf){width="6.041666666666667in" height="4.96875in"}

## SystemS

> Ring 12: Titanium-Kevlar-Phenolic
>
> Ring 21: Steel-Fiberglass-Polyester
>
> Rings 11, 16, and 25: Kevlar-Phenolic
>
> Ring 31: Fiberglass-Aluminum
>
> Ring 28: Fiberglass Polyester
>
> Rings 32 and 30: Kevlar-Aluminum

FIGURE 50. THICKNESS INCREASE VERSUS PENETRATING DURATION

Tables 5 and 6 summarizes the kinetic energy per weight, energy per
thickness, and rankings of the ten systems selected in order from the
highest to lowest ranking.

Based on the energy per weight and thickness, as seen in tables 5 and 6,
the aluminum-lined fiberglass system has the highest energy per weight,
62 kips/lb, and hence has the highest KE~w~ ranking. The titanium system
has the highest energy per thickness ranking, 2,168 kips/in, and hence
has the highest KE~t~ ranking. A combined ranking score was established
by multiplying the weight to thickness rankings. Fiberglass impregnated
with phenolic resin has the highest score as seen in table 7. The
aluminum-lined fiberglass system came in second. The fiberglass
impregnated with polyester came in third. Since the energy per weight is
considered critical, the aluminum-lined fiberglass system, therefore,
represents an optimum system based on its energy per weight. It is
interesting to recognize that three out of the top five systems in E~w~
ranking had fiberglass. Four out of the top five systems in E~t~ had
fiberglass. In the combined rankings, four out of the top five systems
were also fiberglass.

TABLE 5. RANKINGS OF CONTAINMENT RINGS BASED ON ENERGY PER WEIGHT

> (CONTAINED ALL FRAGMENTS)

  ---------- ---------------------------- ----------------------- ----------
  Ring No.   Materials                    KE/W~t~ x1000           Rankings
                                          (in.lbs/lb)             

  36         Fiberglass-Al Liner          62                      10

  33         Kevlar-Al Liner              57                      9

  26         Fiberglass-Phenolic          51                      8

  22         Kevlar 29                    50                      7

  17         Fiberglass-Polyester         49                      6

  15         Ti-Kevlar-Phenolic           36                      5

  1          Kevlar 29-Phenolic           34                      4

  19         Steel-Fiberglass-Polyester   31                      3

  18         Titanium (6A14V)             31                      2

  13         Steel-Fiberglass-Phenolic    30                      1
  ---------- ---------------------------- ----------------------- ----------

TABLE 6. RANKINGS OF CONTAINMENT RINGS BASED ON ENERGY Per

> THICKNESS (CONTAINED ALL FRAGMENTS)

  ---------- ---------------------------- ----------------------- -----------
  Ring No.   Materials                    KE/t~r~ x1000           Rankings
                                          (in.lbs/in)             

  18         Titanium (6A14V)             2168                    10

  13         Steel-Fiberglass-Phenolic    1698                    9

  26         Fiberglass-Phenolic          1650                    8

  19         Steel-Fiberglass-Polyester   1591                    7

  17         Fiberglass-Polyester         1527                    6

  15         Ti-Kevlar-Phenolic           1347                    5

  36         Fiberglass- Al Liner         1303                    4

  33         Kevlar 29-Al Liner           910                     3

  22         Kevlar 29                    605                     2

  1          Kevlar 29-Phenolic           598                     1
  ---------- ---------------------------- ----------------------- -----------

TABLE 7. COMBINED RANKINGS OF CONTAINMENT RINGS

> (CONTAINED ALL FRAGMENTS)

  --------- ---------------------------- ------------- ------------- ----------------
  Ring No.  Materials                    Weight        Thickness     Combined Ranking
                                         Rankings      Rankings      Scores

  26        Fiberglass-Phenolic          8             8             64

  36        Fiberglass- Al Liner         10            4             40

  17        Fiberglass-Polyester         6             6             36

  33        Fiberglass-Al Liner          9             3             27

  15        Ti-Kevlar-Phenolic           5             5             25

  19        Steel-Fiberglass-Polyester   3             7             21

  18        Titanium (6A14V)             2             10            20

  22        Kevlar 29                    7             2             14

  13        Steel-Fiberglass-Phenolic    1             9             9

  1         Kevlar 29-Phenolic           4             1             4
  --------- ---------------------------- ------------- ------------- ----------------

Based on the results of phase 1, the aluminum lined fiberglass ring was
the best system so far, and it was selected for further testing under
elevated temperatures. Three OCF S2 dry fiberglass, bonded to a
0.0625-inch aluminum liner by GE SR240 silicon, containment rings were
fabricated. Only ring 40 contained all rotor fragments under elevated
temperatures. However, a small hole, approximately one inch, was found
on the ring. It appeared that a small fragment, probably a small piece
of blade debris with low energy, penetrated the containment ring. By the
time blade debris escaped the ring, its energy was further reduced due
to energy absorption of the ring and, hence, probably became less
harmful.

Three type "J" thermocouples (TCs) were used for ring 40 and located at
the laminate/aluminum interface, at the 22nd, and at the 43rd ply. TCs 2
and 3 were fiberglass insulated and able to withstand the higher
temperatures better than the Teflon sleeved wire. Normalized weight and
thickness of ring 40 were 30.27 lbs and 2.10 inches. KE~w~ and KE~t~
were 31 kips/lb and 432 kips/in respectively. One disc fragment
penetrated and escaped ring 38. Another disc fragment penetrated and
almost escaped the ring. Tables 8 and 9 show the containment ring
characteristics and their performance. Figures 51 shows the posttest
pictures of ring 38. Figure 52 shows the failure event of rings 38.
Figure 53 shows the failure event and pre- and posttest pictures of
ring 40.

TABLE 8. HEATED CONTAINMENT RINGS

  ------ --------------- -------- ------------ ------------ -------- ------------ -------- ----------- -------------
  Ring   Materials       Weight   Normalized   Radial       Axial    No. of       Failed   Contained   Test
  No.                    (lbs)    Weight (lbs) Thickness    Length   High-Speed   Speed    (C) or Not  Temperature
                                               (in)         (in)     Photos       (rpm)    Contained   (^°^F)
                                                                                           (NC)        

  38     Fiberglass-Al   19.00    18.83        0.63/063     9.08     48           21260    NC          596-869
         Liner                                                                                         

  39     Fiberglass-Al   29.00    29.00        0.94/0.063   9.00     0            20400    NC          510-780
         Liner                                                                                         

  40     Fiberglass-Al   37.00    30.27        2.1/0.06     11.00    50           20224    C           504-878
         Liner                                                                                         
  ------ --------------- -------- ------------ ------------ -------- ------------ -------- ----------- -------------

TABLE 9. HEATED CONTAINMENT RING PERFORMANCE

> (CONTAINED ALL FRAGMENTS)

<table>
<colgroup>
<col style="width: 6%" />
<col style="width: 12%" />
<col style="width: 7%" />
<col style="width: 10%" />
<col style="width: 10%" />
<col style="width: 7%" />
<col style="width: 10%" />
<col style="width: 8%" />
<col style="width: 14%" />
<col style="width: 11%" />
</colgroup>
<tbody>
<tr class="odd">
<td>Ring No.</td>
<td>Materials</td>
<td>Weight (lbs)</td>
<td>Normalized Weight (lbs)</td>
<td><p>Radial Thickness</p>
<p>(in)</p></td>
<td>Axial Length (in)</td>
<td>KE<sub>w</sub> x1000 in-lbs/lb</td>
<td>KE<sub>t</sub> x1000 in-lbs/in</td>
<td><p>Contained (C) or Not Contained</p>
<p>(NC)</p></td>
<td>Test Temperature (<sup>°</sup>F)</td>
</tr>
<tr class="even">
<td>40</td>
<td>Fiberglass-Al Liner</td>
<td>37.00</td>
<td>30.27</td>
<td>2.1/0.06</td>
<td>11.00</td>
<td>31</td>
<td>432</td>
<td>C</td>
<td>504-878</td>
</tr>
</tbody>
</table>

Under the high temperature, the absorption capability of the fiberglass
material is significantly reduced. This reduction results in an increase
of approximately 92 percent in material weight and 304 percent in
thickness. Its E~w~ and E~t~ are reduced about 50 and 33 percent
respectively.

It may not be correct to assume that all other composite systems would
behave exactly similar to the fiberglass system under the high
temperature. Other composite systems, i.e., dry aramid or aramid
impregnated with different types of resins, could have been selected for
testing under the high temperature to assess their performance and
compare it with the performance of the fiberglass system. Aramid, such
as Kevlar 29, performed almost the same as fiberglass at ambient
temperature. Only the fiberglass system was selected for high
temperature testing.

#### ![](media/image52.emf){width="6.495833333333334in" height="5.595833333333333in"}

FIGURE 51. POSTTEST PICTURES OF RING 38

#### 

![](media/image53.emf){width="5.7652777777777775in"
height="8.065972222222221in"}

FIGURE 52. FAILURE EVENT OF RING 38

![](media/image54.emf){width="6.497222222222222in"
height="7.195138888888889in"}

FIGURE 53. FAILURE EVENT AND PRE/POSTTEST PICTURES OF RING 40

# 7. CONCLUSIONS.

a.  Under phase 1, based on the energy per weight, we have successfully
    identified fiberglass as the best lightweight material so far. Dry
    aramid, Kevlar 29, with an aluminum liner performed almost as
    effectively as fiberglass under ambient conditions.

b.  Fiberglass systems, with compromised weight and thickness, still
    outperformed other composite systems.

c.  Based on the energy per weight or thickness, dry Kevlar 29 performed
    better than Kevlar impregnated with phenolic resin. Dry Kevlar
    appeared to prolong the penetrating duration.

d.  Under the average temperature of 691°F, in phase 2, the performances
    of the aluminum lined fiberglass system, based on energy per weight
    and thickness, are reduced by 50 and 33 percent respectively. An
    increase of 92 percent in containment ring weight and 304 percent in
    its thickness are required to compensate for the degradation of the
    fiberglass system under high temperatures.

e.  Fabric composite systems absorbed the kinetic energy of fragments
    through elastic deformation and interlaminated shear of composite
    layers. No evidence of tensile failure of fibers existed.

# 8. REFERENCES.

1.  Deluca, J. J., [Development of Turbine Containment for
    Aircraft]{.underline}, Ph.D. Thesis, University of Lowell, Lowell,
    MA, September 1991.

2.  Mascianica, F. S., [Ballistic Technology of Lightweight Armor1979
    (U),]{.underline} pg. 566, AMMRC TR 7910, February 1979.

3.  Dy, L. D., [Aircraft Engine Fragment Containment Simulation Theory
    and Application]{.underline}, M.S. Thesis, The Pennsylvania State
    University, Malvern, October 1992.

4.  Cheng, W. F. and Han, D. J., [Plasticity for Structure
    Engineers]{.underline}, pages 409-427, New York: Spring-Verlag New
    York Inc., 1988.

## APPENDIX AKINETIC ENERGY OF DISK FRAGMENTS

The transitional kinetic energy of the pie-shaped sector is

KE~t~ = $\frac{1}{2}$mV^2^ = $\frac{1}{2}$m($\overline{r}$ω)^2^ (1)

where V is the centroid linear velocity of mass m with angular velocity
ω with respect to y axis

m = ρυ (2)

where ρ is the density and υ is the volume of the sector.

Assume $f$is very small, then

υ =$\int_{\text{ri}}^{r0}{}$r$f$tdr (3)

where

t = $\frac{\text{dt}(r)}{\text{dr}}$ = t'(r)

Substitute equation 3 into equation 2, we obtain

m = ρ$f$$\int_{\text{ri}}^{r0}{}$rt'(r)dr = ρ $f$R~y~ (4)

where R~y~ is the first moment of dA with respect to y axis.

Also

$\overline{r}$A = $\int_{\text{ri}}^{r0}{}$$\overline{r}$~el~dA (5)

where $\overline{r}$~el~ is the centroid of element dA as seen in figure
A.1.

Since

$\overline{r}$~el~ = $\frac{r\text{sin}f}{f}$ (6)

dA = tdr = t'(r)dr (7)

A = $\int_{\text{ri}}^{r0}{}$t'(r)dr (8)

Substitute equations 6, 7, and 8 into equation 5, then

> $\int_{\text{ri}}^{r0}{}$$\frac{\text{sin}f}{f}$rt'(r) dr
>
> $\overline{r}$ = (9)
>
> $\int_{\text{ri}}^{r0}{}$t'(r)dr

Multiply the denominator and nominator of equation 9 by $\frac{r}{r}$,
we have

> $\frac{\text{sin}f}{f}$$\int_{\text{ri}}^{r0}{}$r^2^ t'(r)dr
>
> $\overline{r}$ = (10)
>
> $\int_{\text{ri}}^{r0}{}$rt'(r)dr

Let R~y~ and M~y~ be the first and second moment of dA with respect to y
axis, then

R~y~ = $\int_{\text{ri}}^{r0}{}$rt'(r)dr (11)

and

M~y~ = $\int_{\text{ri}}^{r0}{}$ r^2^t'(r) dr (12)

Substitute R~y~ and M~y~ into equation 10, we obtain

$\overline{r}$ = $\frac{\text{sin}f}{f}$.$\frac{My}{Ry}$ (13)

Therefore,

V = $\overline{r}$ω = $\frac{\text{sin}f}{f}$.$\frac{My}{Ry}$ω (14)

Substitute equations 4 and 14 into equation 1, we obtain

> KE ~t~=$\frac{1}{2}$mv^2^ = $\frac{1}{2}$ρω^2^
> $\frac{\text{sin}^{2}fM_{y}^{2}}{{fR}_{y}}$$$ (15)

First and second moment of dA, as seen in figure A.2, with respect to y
axis are also expressed as

R~y~ = $\int_{A}^{}{}$rdA = $\int_{A}^{}{}$($\overline{r}$ + r')dA
=$\int_{A}^{}{}$$\overline{r}$dA + $\int_{A}^{}{}$r'dA = $\overline{r}$A
(16)

where

$\int_{A}^{}{}$$\overline{r}$dA =$\overline{r}$A and $\int_{A}^{}{}$r'dA
= r'A = 0 as area A rotates about its own axis AA'

> M~y~ = $\int_{A}^{}{}$ r^2^dA = $\int_{A}^{}{}$($\overline{r}$ +
> r')^2^dA = $\int_{A}^{}{}$($\overline{r}$^2^dA + 2$\overline{r}$r'dA +
> r'^2^dA)

$\int_{A}^{}{}$$\overline{r}$^2^dA = A$\overline{r}$^2^

$\int_{A}^{}{}$`<!-- -->`{=html}2$\overline{r}$r'dA = 2$\overline{r}$r'A
= 0 as area A rotates about its own axis AA'

$\int_{A}^{}{}$r'^2^dA = M~AA'~

Therefore,

M~y~ = M~AA'~ + A$\overline{r}$^2^

Also M~AA'~ = k~g~^2^A where k~g~ is the radius of gyration of area A
with respect to y axis.

M~y~ = k~g~^2^A + A$\overline{r}$^2^ = (k~g~^2^ + $\overline{r}$^2^)A
(17)

Finally,

> $\text{KE}_{t} = \frac{\text{ρv}^{2}\text{sin}^{2}f\left\lbrack \left( k_{g}^{2} + \overline{r} \right) \right\rbrack^{2}A}{2f\overline{r}}$
> (18)

The maximum translational kinetic energy occurs when equation 18 is
minimized. Let

u = sin^2^$f$ , $\frac{\text{du}}{df}$ = 2sin$f$cos$f$ (19)

v = $f$ ,$\frac{\text{dv}}{df}$ = 1 (20)

$\frac{d(\text{KE}_{t})}{df} = \frac{{\rho Av}^{2}\left( k_{g}^{2} + {\overline{r}}^{2} \right)^{2}\left\lbrack 2f\text{sin}f\text{cos}f - \text{sin}^{2}f \right\rbrack}{2f^{2}\overline{r}} = 0$$$
(21)

Solving equation 21 gives the maximum translational kinetic energy at
$f$ = 66.8°. The maximum translational kinetic energy of the whole
sector (2$f$) is, therefore, 133.6°.

The rotational kinetic energy can be calculated from

KE~total~ = KE~t~ + KE~r~ (22)

where

KE~total~ = $\frac{1}{2}$mv^2^ + $\frac{1}{2}$M~y~ω^2^ (23)

and M~y~ is the second moment of inertia of the fragment with respect to
y axis.

The distributions of the translational and rotational kinetic energy,
therefore, are

KE~t~ (%) = $\frac{\text{KE}t}{\text{KE}\text{tota}l}$ (24)

or

KE~r~ (%) =$\frac{\text{KE}r}{\text{KE}\text{tota}l}$ = \[1 - KE~t~
(%)\] x 100 (25)

APPENDIX BROTOR FRAGMENT GENERATOR ANALYSIS

Limit analysis is used to calculate the size of one or more precut
notches. These notches will cause the failure of the rotor at a speed
which produces 1.0 x 10^6^ in-lbs of the kinetic energy.

To simplify the problem, assume that the T53 turbine rotor was made of
an elastic, perfectly plastic material and was notched as shown in
figure B-1. As the rotor is gradually spinning, starting from the center
of the rotor, the rotor grows elastically until the stress located at
the high stress concentration area reaches the yield stress.

σ ~ij\ =~ σ ~y~ (1)

In this case, the plastic zone will initially start from the end of the
cut, point A, and move inward to the inner radius surface of the rotor.
Further increases in speed will cause the plastic zone to spread, but it
is still contained inside the elastic zone. As the rotor approaches its
burst speed,

N = N~burst~ (2)

The elastic zone is no longer dominant, and the entire section from
point A to the inner radius is covered by the plastic zone.
Theoretically, point A′ will experience the same yield process and
eventually reach the ultimate stress at the same time as point A. At
this burst speed, the material of the rotor reaches its limit stress or
ultimate stress, and the rotor will burst into a predetermined number of
fragments.

According to Chen and Han \[4\], when an equilibrium stress distribution
which balances the applied load is found, plastic flow will not occur.
From the equilibrium stress distribution, a lower bound solution for the
size of the notches can therefore be estimated.

An upper bound solution is determined by equating the rate of the work
done by the external forces to the rate of the internal energy
dissipation. The upper bound theorem considers only the compatible
velocity field which satisfies the constraints, and the stress
distribution is not necessary in equilibrium.

As a simplification, assume that the disk was spinning and was broken in
half by the centripetal force applied to the unnotched region as shown
in figure B-2. The variable b defines the distance from the center of
the disk to the end of the cut (b-cut), a defines the inner radius and t
defines the thickness of the disk which is assumed to be constant. Then
(b - a) is the length of the material left after cutting. The internal
stress in the contract area may be expressed as,

σ ~i~ = $\frac{Fc}{2(b - a)t}$ (3)

or F~c~ = 2(b - a)tσ ~i~ (3a)

![](media/image55.emf){width="3.5194444444444444in"
height="2.984027777777778in"}

> LEGENDS:
>
> a = disk inner radius
>
> b = slot terminal radius
>
> r~0~ = outer disk radius
>
> F~c~ = centripetal force
>
> t = disk thickness
>
> ω = angular velocity
>
> c = cut length

FIGURE B-1. NOTCHED DISK LIMIT ANALYSIS DIAGRAM

![](media/image56.emf){width="4.76875in" height="3.9034722222222222in"}

FIGURE B-2. VELOCITY FIELD OF THE NOTCHED DISK AT FAILURE

but F~c~ = m„ (3b)

and m = $\frac{Wt}{g}$ (3c)

then

$\overset{}{\overline{r}}$π^2^N^2^

„ = $\overset{}{\overline{r}}$ω^2^ = (3d)

900

where

m = mass of fragment

w~t~ = fragment weight

g = gravity constant

$\overset{}{\overline{r}}$ = fragment centroid

ω = angular velocity

N = rotation per minute

„ = acceleration

a = inner radius

equations 3-3d can be combined as

w~t~$\overset{}{\overline{r}}$π^2^N^2^

= (2)(b - a)tσ ~i~ (4)

900g

At collapse, σ~i~ = σ ~u~ = ultimate stress. Substituting σ ~u~ into
equation 4 yields

w~t~$\overset{}{\overline{r}}$π^2^N^2^

= (2)(b - a)tσ ~u~ (4a)

900g

w~t~ $\overset{}{\overline{r}}$π^2^N^2^

or b = a + (4b)

1800gtσ ~u~

Let c equal the minimum cut length and r~0~ be the outer radius of the
disk, then

b = r~0~ - c (5)

equation 4b becomes

w~t~$\overset{}{\overline{r}}$π^2^N^2^

c = (r~0~ - a ) - (6)

1800gtσ ~u~

Equation 4b gives us the lower bound solution which predicts that at
burst or collapse speed the actual b-cut would be equal or larger than
the lower bound b-cut, b~1~.

Figure B-2 shows the kinematically admissible velocity field in which
the upper and lower half of the disk move as rigid bodies relative to
each other along plane CD. If the relative velocity of plane CD is δ~h~,
then, the internal energy dissipation is

Di = (1 cut)(2k)(b-a)tδ~h~ (7)

where k is the yield parameter or collapse parameter in this case.

If the velocity at which the upper and lower disk are separated is δ~v~,
the external work is

w~t~$\overset{}{\overline{r}}$π^2^N^2^δ~v~

D~e~ = F~c~δ~v~ = (8)

900g

By setting equation 7 equal to equation 8, the upper bound b-cut
solution may be derived,

w~t~$\overset{}{\overline{r}}$π^2^N^2^δ~v~

(1 cut)(2k)(b-a)tδ~h~ = (9)

900g

Due to symmetry,

δ~h~ = δ~v~

then,

w~t~$\overset{}{\overline{r}}$π^2^N^2^

b = a + (10)

1800gtk

The cut is obtained as

w~t~$\overset{}{\overline{r}}$π^2^N^2^

c = (r~0~ - a) - (11)

1800gtk

Since we model the disk as an elastic, perfectly plastic material, no
work-hardening exists, then the stress in the disk may be assumed to be
constant after yielding. Also since we are interested only in the disk
burst, then

σ ~y~ = σ ~u~ (12)

The maximum shear stress or Tresca yield criterion predicts that
yielding will occur where the constant k reaches a critical value such
that

σ ~u~

k = (12a)

2

Substituting equation 12a into equation 10 yields

w~t~$\overset{}{\overline{r}}$π^2^N^2^

b = a + (13)

900gtσ ~u~

The distortion energy or Von Mises yield criterion predicts that k may
be expressed as

σ ~u~

k = (13a)

3^1/2^

After the appropriate substitution of equation 13a, equation 10 becomes

w~t~$\overset{}{\overline{r}}$π^2^N^2^

b = a + (14)

1039gtσ ~u~

Figure B-3 shows the plot of speed versus the b-cut length which begins
at the end of the cut and stops at the disk center. From the
experimental test data, the actual b-cut curve when plotted lies to the
right of the lower bound curve and is close to it. The two lines on the
right side of the actual b-cut curve demonstrate the difference between
Von Mises and Tresca yield criteria, and the Von Mises yield criterion
seems to be closer to the true b-cut than Tresca. The area between the
lower bound and Von Mises upper bound curves therefore estimates the
b-cut length corresponding to the design speed.

Due to the aging of the rotors which had been used in service, however,
there is a definite discrepancy between the design and test data. The
lower and upper bound b-cut curves are, therefore, sufficient to
represent the fragment generator design guide curve for the T53 turbine
rotors.

![](media/image57.emf){width="4.925in" height="5.8381944444444445in"}

FIGURE B-3. DESIGNED b-CUT LENGTH VERSUS EXPERIMENTAL b-CUT LENGTH