# Presentation: 036337

## Study of Orbiter-like Cargo Carrier on 

**Crew Launch Vehicle**
**October 25, 2006**
**FEMCI Workshop 2006**
**Goddard Space Flight Center, Greenbelt, Maryland**
**Zoran N. Martinovic**

## 			Content:

**On CLV**

**	****	****	****Content:**
**• ****Study objective and requirements**
**• ****Vehicle size and two candidate designs**
**• ****Structural requirements, loads and interfaces**
**• ****Outline of analytical process**
**• ****Details of two designs and analytical weight prediction**
**• ****Non-optimal weight estimates**
**• ****Summary**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## 			Objective:

**On CLV**

**	****	****	****Objective:**
**• ****Design and determine primary structures analytical **
**weight for an Orbiter-like Cargo Carrier concept that **
**was examined during the early phase of the Crew **
**Launch Vehicle (CLV ) program to fly attached on **
**top of CLV**
** ****• ****This vehicle is not part of the current program**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## 		Design Requirements:

**On CLV**

**	****	****Design Requirements:**
**• ****Cargo Carrier was envisioned to enable delivery **
**of all  International Space Station (ISS) elements **
**(15 ft dia., 48 ft length, 55,000 lb weight)**
**in Orbiter like payload accommodation environment **
**• ****No modifications of existing payload hardware **
**was required**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## Size

**• ****Inner diameter equaled Orbiter’s inner diameter of 15 feet (4.57 meters)**
**• ****Outer diameter was 18 feet (5.49 meters)**
**• ****Length of Cargo Bay equaled the useful length of Orbiter Payload Bay when Orbiter was configured with ISS external airlock and Orbiter Docking Structure, 598 inch or 49.8 feet (15.2 meters).**

**Orbiter-like Cargo Carrier**
**On CLV**

**2 ft**

**49.8 ft**

**16.7 ft**

**18 ft Out. Dia**
**15 ft In. Dia.**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## Design

**Two designs were considered and sized**
**• **_**Open Wall Design**_** that consisted of stiffened skin with stringers, longerons and frames.**
**• **_**Closed Wall Design**_** that had outer stiffened skin closed with inner skin that resists torque loads.**

**Orbiter-like Cargo Carrier**
**On CLV**

**Open Wall Design**

**Closed Wall Design**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## Design (cont.)

**Cargo Bay doors were designed and sized**
**and there influence factored in the Closed**
**Wall Design sizing of Cargo Carrier**

**Orbiter-like Cargo Carrier**
**On CLV**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## 	Structural Requirements

*** ****Space Shuttle System Payload Accommodations, NSTS 07700 Vol. XIV **

**	****Structural Requirements**
**• ****Payload attachments were like in Orbiter and statically determinate ***
**• ****Load Factors: axial 4g, lateral 1g (1.41 g lateral combined).**
**• ****Safety Factor (Ultimate Load/Limit Load) equal to  1.5**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

**Orbiter-like Cargo Carrier**
**On CLV**

## 			Loads 

**• ****Six sets of combined loads **

**• ****Inertia loads due to acceleration: axial 4g, lateral 1g (1.41g for lateral combined).**
**• ****Aero loads due to dynamic pressure of 850 psf: drag and lateral, CD=0.05, CL=0.01 **
**(CL=0.014 for lateral combined) M>2 and Alpha = 1 deg (Bruhn – Saturn V*).**

*** ****Analysis and Design of Missile Structures, E.F. Bruhn, Tri-State Offset Co., 1967**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

**Orbiter-like Cargo Carrier**
**On CLV**

##       Payload and Payload attachment

**On CLV**

**      ****Payload and Payload attachment**
** **
**• ****Payload weight 55,000 lb (25,000 kg)**
**• ****Payload modeled as a lump mass with inertia properties of a cylinder 500 inch long and 168 inch diameter  **

**Payload**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## 	Carrier attachment to launch 	vehicle/service module 

**On CLV**

**	****Carrier attachment to launch ****	****vehicle/service module **
**• ****Six ball joints at longerons (60 deg. apart) **

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## Process Outline

- Vehicle Geometry and Weights
**CONSIZ**

**I-DEAS** FE Model

**POST ** Flight Profile with Accelerations & **CBAERO** generated Aero-forces

- Loaded **I-DEAS** FE Model

**HSLoad / HYPERSIZER** Model

- Panel sizing in
** ****HYPERSIZER**

- Load Balancing
**EXCEL Solver**

- [M], [K]
- Finite elements
- organized in
- groups/Panels

- Running loads [Nx, Ny, Nxy ......]

-  Panel/beam Concept
-  Material
-  Limits on design variables
-  Failure Criteria

- Assign:

- New [K] &
- Struct. [M]

**LOFT** Generated Mesh

**INPUT**
**Geometry**

- I T E R A T I O N    L O O P

**INPUT**
**Lump Mass**

**INPUT**
**Gs & Fs**

**INPUT**
**FE Mesh**

**Process Outline**

**Orbiter-like Cargo Carrier**
**On CLV**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

**Notes:**
Plans for the future
Apply a semi-automated iterative procedure for structural weight estimation of new launch vehicle designs within CoHAVE environment for Level 2 design.
Compare the estimated weight with the Level 1 predictions.

## Open Wall Design 

**On CLV**

**Open Wall Design **

**Al 2024-T3**

**Al 2024-T3**

**Al 2024-T3 face-sheets**
**Hexcel 1/8-5052-.0015 core**

**Al 7075-T6**

**Frame spacing 59.8 inch**
**Longeron spacing 60 deg. **

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## Earlier study showed: 

**On CLV**

**0.88 lbs/sq.ft**

**1.16 lbs/sq.ft**

**1.23 lbs/sq.ft**

**1.52 lbs/sq.ft**

_**Panel concept**_

_**Unit weight**_

**Earlier study showed: **

**Combined fixed/simply **
**supported aluminum panel **
**36 inch x 80 inch, **
**radius 108 inch**
**loaded with 1000 lb/in **
**Ultimate Load = 1.5 Applied**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## Open Wall Design (cont.)

**On CLV**

**Open Wall Design (cont.)**
**• ****Sizing of panels and beams done by an iterative  process between UGS/I-Deas (analysis) and Collier/HyperSizer (sizing) tools.**

| Iteration | Weight (lbs) |
| --- | --- |
| 1 | 12,408 |
| 2 | 13,671 |
| 3 | 15,104 |
| 4 | 14,944 |
| 5 | 15,307 |

**W = 15,307 lbs = 5,333 lbs (Panels) + **_**9,974**_** lbs (Beams)**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## Closed Wall Design 

**Orbiter-like Cargo Carrier**
**On CLV**

**Closed Wall Design **

**Al 2024-T3**
**Outer skin**

**Al 2024-T3**

**Al 2024-T3 face-sheets**
**Hexcel 1/8-5052-.0015 core**

**Al 7075-T6**
**Beam Caps**

**Inner Skin**

**Beam webs**

_**Beam **_
_**Cross**_
_**Section**_

**Sandwich**

**Extrusion**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## Closed Wall Design (cont.)

**On CLV**

**Closed Wall Design (cont.)**
**• ****Same process used for sizing as in Open Wall Design**

| Iteration | Weight (lbs) |
| --- | --- |
| 1 | 8,643 |
| 2 | 7,858 |
| 3 | 8,062 |
| 4 | 8,171 |

**W = 8,171 lbs = 6,675 lbs (Panels) + **_**1,496**_** lbs (Beam Caps)**

| Open Wall Weight (lbs) | 15,307 |
| --- | --- |
| Closed Wall Weight (lbs) | 8,171 |

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## Adding symmetry  to the Closed Wall Design

**On CLV**

**Adding symmetry  to the Closed Wall Design**
**• ****Optimization produces an asymmetric structure**
**about the central vehicle plane due to asymmetric loads**

| Sym. Closed Wall Weight (lbs)
After 5th Iteration | 10,525 |
| --- | --- |
| Closed Wall Weight (lbs) | 8,171 |

**Unit weight (lb/sqft)**

**Unit weight (lb/sqft)**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## Cargo Bay Doors Design

**Cargo Bay Doors Design**
**• ****The same six combined aero/inertia loads were **
**applied as for the rest of the vehicle.**
**• ****Four ball joints modeled doors attachments to the vehicle.**

**Al 2024-T3 face-sheets**
**Hexcel 1/8-5052-.0015 core**

**Al 7075-T6**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

**Orbiter-like Cargo Carrier**
**On CLV**

## Cargo Bay Doors Design (cont.)

**On CLV**

**Cargo Bay Doors Design (cont.)**
**• ****During the last iteration, constraint forces, caused by door loads, were computed at hinge**
**locations and saved for further design**

| Iteration | Weight (lbs) |
| --- | --- |
| 1 | 1,596 |
| 2 | 1,483 |
| 3 | 1,484 |

**W = 1,484 lbs = 1,333 lbs (Panels) + 151 lbs (Beams)**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## Closed Wall Design with Bay Doors loads

**On CLV**

**Closed Wall Design with Bay Doors loads**
**• ****Six sets of ****concentrated loads on cargo bay hinges added to six load cases**

| Iteration | Weight (lbs) |
| --- | --- |
| 1 | 7,882 |
| 2 | 7,897 |
| Symmetry run | 10,613 |

**W = 10,613 = 8963 lbs (Panels) + 1,650 lbs (Beam Caps)**

|  Weight no hinge loads (lbs) | 10,525 |
| --- | --- |
| Weight with hinge loads (lbs) | 10,613 |

**Total vehicle primary structure weight (with doors) = 10,613+1,484 = 12,097 lbs (5,499 kg)**

**Note:**
**One out of **
**six loads shown**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

## 	Non Optimal Weight Estimates

**  **
**• ****12,097 lb is weight of **_**primary analytical**_** structure**
**• ****Assume that non optima and secondary structure **
**add 15% to the weight:**

**Total structural “as-built weight” **
**estimate  would be 13,912 lb**

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**

**Orbiter-like Cargo Carrier**
**On CLV**

## 			Summary

**On CLV**

**	****	****	****Summary**
**• ****Process for rapid design and structural weight estimation was applied to Orbiter-like Cargo Carrier**
**• ****Two structural design concepts were analyzed**
**and one of them – Closed Wall Design was selected **
**as a superior among the two**
**• ****Process produced analytical structural weight **
** ****of 12,097 lb **
**• ****Estimated total structural weight, with non-optimal**
**weight and secondary structure weight, was ****13,912 lb**** **

**Zoran N. Martinovic/NASA LaRC/VAB October 2006**