Historical Perspectives on

Vulnerability/Lethality Analysis

by J. Terrence Klopcic

and Harry L. Reed

EDITORS

ARL-SR-90

Approved for public release; distribution is unlimhd.

April 1999
The findings in this report are not to be construed as an official

Department of the Army position unless so designated by other

authorized documents.

Citation of manufacturer’s or trade names does not constitute an

official endorsement or approval of the use thereof.

Destroy this report when it is no longer needed. Do not return

it to the originator.
Army Research Laboratory

Aberdeen Proving Ground, MD 21005-5068

ARL-SR-90 April 1999

Historical Perspectives on

Vulnerability/Lethality Analysis

J. Terrence Klopcic

Survivability/Lethality Analysis Directorate, ARL

Harry L. Reed

Consultant

EDITORS

Approved for public release; distribution is unlimited.
Abstract

Commencing in the early 199Os, Mr. James O’Bryon of the Offrce of the Secretary of

Defense (OSD), Operational Testing and Evaluation (OT&E), charged the Vulnerability/

Lethality Division (VLD) of what is now the U.S. Army Research Laboratory (ARL) to capture

in a hard-bound book the art/science of vulnerability and lethality (V/L) analysis. This work has

since expanded into the publication of a series of volumes, each dedicated to a particular portion

of the V/L community-ground mobile targets, hardened fixed targets, aircraft, etc.

As a first step in this mammoth effort, a number of articles were commissioned to be

gathered from some of the giants in the history of V/L analysis. These articles gave a foundation

from which the writing of the first of the series commenced and are collected in this report with

the hope that future generations of V/L analysts will find in them inspiration for their own

accomplishments.

ii
Preface

One morning in June of 1990, I found myself sitting in a conference room in La Jolla, CA,

waiting to brief the JASONs, a group of approximately 60 leading academics from across the nation

who consult annually on a myriad of defense-related issues. Mr. Dick Vitali, Acting Director of the

U.S. Army Laboratory Command (LABCOM), had requested a review of the U.S. Army Ballistic

Research Laboratory (BRL) vulnerability/lethality (V/L) program by the JASONs. Such an

examination was timely as it had been barely 5 years since the inception of the Live Fire legislation.

A number of weapon platforms had been tested, and significant variances had been observed

between test and model outcomes. Many practices and strategies were due a reexamination. As I

awaited my opportunity to brief the committee, Mr. Art Stein was presenting material, some of it

gathered as much as 50 years ago. As I listened to the presentation, I was as much struck by the

human and historical elements as the quality and breadth of the technical message. I decided right

then that it was important to bring Art Stein and his message to BRL, particularly for the younger

people to experience.

In the fall of 1992, BRL was reformed and merged into the U.S. Army Research Laboratory .

(ARL). To celebrate the many contributions made in the field of V/L, we invited Art Stein, Dave

Hardison, and a host of senior analysts back to the lab to review our recent accomplishments and to

have them discuss key activities of the past. This volume reproduces a number of those

presentations from “Vulnerability Day.”

A separate project initiated by Mr. James F. O’Bryon, Director, Live Fire Testing, Office of the

Secretary of Defense, has focused on the development of a V/L Handbook. Early on, we expected

to present a number of articles discussing early vulnerability history. As that document has evolved

in other directions, it seemed valuable and prudent to make these hitherto-unpublished manuscripts

available to the community at large.

Particular thanks goes to Dr. J. Terrence Klopcic and Mi-. Harry L. Reed, Jr., for bringing these

historical threads to these pages.

&dgDirec

U.S. Army Mateiel

to r

ystems Analysis Activity

(formerly Chief of ARL’s Vulnerability/Lethality

Division, October 1990 to November 1997)

. . .

Ill
bITENTIONALLY LEFT BLANK.

iv
Table of Contents

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Preface . . . . . . ..~~...~...~~*...~.~.~~~~~~~...~.~~.~~..~~~..~.~.~~~~

Introduction . . . . . . . . ..0.~.0.0~~~~.~~~.~....~......................

Deveiopment of the Ship Design Vuhrerabiiity Analysis Process

Robert K. Barr .~~...~...~..~~...............~.~...,~~~~~.~~~..~~

On the History of Vuinerabiiity/Lethality Analysis

Roland G. Bernier ~~~~010.00.~~~0~~.~~.OI~..~~~~.~~.~..~~.......~

Reflections Related to Assessment of the Vuinerabiiity of Armored Combat

Vehicles and the Lethality of Antiarmor Munitions: The Last Two-Thirds

of the First Fifteen Years [A Meandering Taie of Unverified Remembrances

of an Aged Analyst, Once of BRL]

Davidson C. Hardison .~..0.~~00.~0~~~~~..~....~~..~.~~~.~~~~.~...

Two Turning Points and a Continuing Improvement

Richurd E. Kinsler .*.....0..*...*.0*........*......*.......~.*..*

Milestones in Modeiing the Vulnerability of Military Personnei to

Fragmenting Munitions

William J. Sacco and Wayne S. Copes 00..0...........................

Excerpts on Vuinerabiiity

Joseph Sperrazza ~0.~~.~00~~~00~00~~0~~~~~~.~..~.....~...~....~~~

IM.orical Vignette on Vuinerabiiity/Lethaiity Anaiysis

Arthur Stein .~~.~~~...~O~D~..~00~~.~~~~.~.~.~.~~~.~...~.~.......

Changes in Vuinerabiiity/Lethaiity Anaiysis Over the Years

Stewart W. Turner ~~~~..00~~~~~~0~000~~~~.~~~~......~..~~~.~....~

The Best and Worst of Times

Lawrence G. Ullyatt ~..~~~DO~.O~O~O.OO~~~~~.~~.~~~...~~~~..~.....~

Distribution List . . . ..~..~..DO~..~.OD~~~~..~~.~..~~.......~.........

Report Documentation Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Bage

. . . 111

1

3

12

20

36

42

55

76

121

128

137

153
INTlWYIONALLY LEFT BLANK.

vi
- 1. Introduction

Commencing in the early 199Os, Mr. James O’Bryon of the Office of the Secretary of Defense

(OSD), Operational Testing and Evaluation (OT&E), charged the Vulnerability/Lethality Division

(VLD) of what is now the U.S. Army Research Laboratory (ARE)’ to capture in a hard-bound book

the art/science of vulnerability and lethality (V/L) analysis. This work has since expanded into the

publication of a series of volumes, each dedicated to a particular portion of the V/L

community-ground mobile targets, hardened fixed targets, aircraft, etc.

As a first step in this mammoth effort, a number of articles were commissioned to be gathered

from some of the giants in the history of V/L analysis. These articles gave a foundation from which

the writing of the first of the series commenced. In addition, the editors of this report were drawn

to a chapter in a report written by Dr. Joseph Sperrazza and compiled by Mr. Alvin Hoffmant

It was noted that these historical articles were irreplaceable treasures in themselves. These

writings include anecdotes, lessons learned, and rules of thumb derived from experiences that will

never again be available to the V/L community. Admittedly, many of the anecdotes have been

overcome by events, the lessons made inapplicable by changes in the field, and the rules replaced

by sophisticated algorithms supported by computing power that was incomprehensible at the time

the rules were formulated. However, as has been so often remarked, “You don’t know where you’re

going if you don’t know where you’ve been.”

For this reason, we have assembled the writings of nine individuals (given in alphabetical order)

into this report. Except for that by David Hardison, these vignettes were obtained from the authors

by TASC under Subtask 5, Contract No. MDA 908-88-G-9056 (J6360-411). Hardison’s reflections

’ The U.S. Army Ballistic Research Laboratory was deactivated on 30 September 1992 and subsequently became apart

of the U.S. Army Research Laboratory (ARL) on 1 October 1992.

+ Sperrazza, J., and A. J. Hoffman. “An Historical Perspective on Weapons Performance.” U.S. Army Materiel

Systems Analysis Activity, Aberdeen Proving Ground, MD, June 1997.

1
were recorded in the Proceedings of Vulnerability Day, which was held on 25 September 1992, at

the U.S. Army Ballistic Research Laboratory9 Aberdeen Proving Ground (A.PG), MD.

Care Ras been taken to limit editorial alteration so that the writings retain as much of their

original tone as possible.

Hopefully, future generations of V/L analysts will fmd in these articles inspiration for their own

accomplishments.

2
2. Development of the Ship Design

Vulnerability Analysis Process

by Robert K. Barr

The development of a ship design vulnerability analysis process has endured varying elements

of resistance from within the ship design community. This resistance has had the effect of retarding

development of a single focus analysis process and resulted in a lack of adequate organization

relative to the many diverse modeling capabilities which support ship design analysis. The impact

of the resistance has been the increased attention regarding design test and evaluation of ship

acquisition by the OffIce of the Secretary of Defense (OSD) and Congress. This attention has

effectively increased OSD’s oversight of the ship design community’s vulnerability assessment

capabilities.

_- March 3,1983, was a unique period to initiate my first tour in the Pentagon. Based on my 32 yr

of experience in damage control, engineering, and operations, I had been asked to accept a position

as the Chemical Warfare Defense and Ship Survivability Officer with the Office of Deputy CNO for

Surface Warfare. The primary focus of that office was to support research and development leading

to acquisition of personnel defense equipment and detection tools for chemical agents. A secondary

responsibility was the management of a seven-ship class survivability improvement backfit program.

This program supported vulnerability reduction primarily for “cheap kill” fragmentation protection

and fire spread. The seven ship classes included cruisers, destroyers, and major amphibious units

totaling 47 ships. This effort was the culmination of several years of accidents and incidents which

had received congressional attention regarding major unit readiness reductions in what some

considered should have had less devastating and fiscally costly results. This was also the period the

results of the British Falkland Islands campaign was impacting the U.S. Navy’s ship design

community. The Falkland’s issue was ship loss due to firespread, including personnel injuries and

deaths from Exocet missiles and their unexpended fuel bum within the impacted ship. It became

obvious to me there were more questions regarding the focus and needed improvements in the ship

survivability design arena than there were answers. This conclusion was soon confirmed in April

3
and May 1983 by two separate directives to me calling for CNBO Executive Board (CEB) reviews

of the Passive Fire Safety (Protection) Program for Ship Design and the entire Ship Survivability

PrOgram.

There were no formal programs for either passive fire protection or ship survivability, which

meant programs must be established in order to comply with CEB requirements. The programs were

established and presented to the CEB in December 1983 and February 1984, respectively, and each

was approved with some additional direction on the overall ship survivability program. That

direction was to plan and implement a survivability backfit program to correct all existing ship

design deficiencies within a 2-yr period. A related objective of the overall ship survivability program

was to establish a military worth assessment process to analyze the value of any given survivability

improvement toward warfighting capability. An additional outcome of the CEB involved the

adequacy and intent of the U.S. Navy’s policy statement regarding Public Law 95-485 titled Navy

Shipbuilding Policy. At that time, the Navy’s 1979 directive simply restated the 1978 Public Law,

but lacked direction or responsibility for implementation. It was concluded the directive lacked

viable meaning regarding the Navy’s intent. Interestingly enough, these three key elements, coming

out of the CEB’s of fiscal year 1984, continue to play a major role relative to the need or design

analysis in support of fiscally sound vulnerability reduction.

The proposal to program the two-year implementation of correction of existing survivability

design deficiencies came from the Chief of the Material Command. The program planning effort

to comply with the CEB direction took 1 yr to complete and only included those ships that would

have 10 yr remaining service life following the alteration installation. The planning included the

man-day work load involved, the number of repair yards available, and the operating schedule for

each ship. When completed, the projected cost for the entire program was $5.8 billion, and the

implementation schedule exceeded 5 yr. It became obvious that Navy’s budget would support

implementation of only the highest priority alterations that provided proven payoff value based on

experience. The paramount conclusion reached from the program analysis was that any survivability

alteration to an operating ship design has a cost ratio of 5: 1 over implementation in the original

4
construction cost. The affordability issue is a turning point relative to providing an analysis of early

implementation of survivability into original ship design.

The idea for a miliary worth assessment was a CEB survivability program recommendation that

grew out of the Naval Sea Systems Command. This idea was intended to utilize the combined

analysis capability of cost and vulnerability assessment computers to determine the most viable

survivability improvements toward maintenance of material readiness supporting warfighting

capability. The objective was to evaluate a baseline ship design and several improvements over that

baseline to identify the most cost-effective means to reduce readiness vulnerability over a range of

one, two, or three weapon impacts. The assessment analysis would actually evaluate the baseline

ship and two to three complete ship designs with increasing survivability improvements to establish

a dollar cost curve relative to the number of hits absorbed while maintaining an acceptable degree

of warfighting capability.

The military worth study effort to develop an analysis program was carried out by the Center for

Naval Analysis (CNA) in 1984 under the direction of a CNO Flag Officer Review Board. CNA

utilized an existing ship design, the DD 993, with several potential improvements in survivability.

The analyst took advantage of the U.S. Navy’s ship vulnerability model and the Naval Sea System

Command’s new ship design cost analysis computer in combination with CNA’s computer to

develop and prove a military worth program for analysis of the value of vulnerability reduction

efforts. The Flag Board was progressively briefed during the development, and upon completion of

the study effort approved the concept. DCNO Surface Ships directed and funded development of

the assessment process within the Systems Command in fiscal year 1985. While the CNOKNA

effort was a turning point supporting vulnerability reduction analysis and proving the capability, the

ship design communities’ resistance to this effort was sufficient that the Systems Command did not

expend the funds to develop and implement the program.

In view of the CNO level criticism regarding the Navy’s shipbuilding policy directive supporting

Public Law 95-485, I initiated action to rewrite the directive to support implementation direction and

assign specific responsibilities. The initial action occurred in July 1984. That action involved the

5
ship design community including experts in vulnerability reduction from Naval Sea Systems

Command. A consensus on implementation needs and responsibilities proved very difficult because

of concerns over everything from classification to details regarding potential for variances on

survivability design specifications. Following development of several strawman drafts of the

instruction to meet the concerns of the participants, it became obvious the survivability and ship

design communities were not going to reach an agreeable conclusion in support of any policy. In

the meantime, other more detailed directives were being developed to support passive fire protection,

shock hardening, and damage control and firefighting. Unfortunately, the products of these

directives would not be subject to any overall assessment process or implementation policy. In 1987,

1 determined the CNO policy statement on survivability was essential and required a new approach.

The approach involved developing a CNO level policy with responsibility, levels of survivability

performance by ship class, and identification of specified weapons effects requiring design

consideration for vulnerability reduction. This directive was signed and implemented in September

1988 as OPNAVINST 9070.1 titled Survivability Policy for Surface Ships of the U.S. Navy. While

the directive was reviewed and approved by the Naval Sea Systems Command, prior to

implementation, and requires that command provide the focus for comprehensive development,

assessment, and implementation of Surface Ship Survivability, to date, no NAVSEA directive has

been implemented to meet that responsibility. Although no implementation directive has been

developed at the NAVSEA level, the OPNAV 9070.1 Instruction has been utilized to provide the

basis for quantification of the vulnerability analysis in ship design.

The increased emphasis on vulnerability reduction in ship design over the past 4 0 yr has resulted

in some positive attempts to improve the analysis capability. The military worth study of 1984 did

result in an attempt to utilize the SW, previously used as a ship design tool, to take on an increased

vulnerability analysis role. This effort was further aided by the development of the fast ship

vulnerability model (Fast SVM) to reduce the analysis time. In the latter 198Os, the development

of a computer support shipboard survivability management approach, titled the Integrated

Survivability Management System (SMS), also supported the analysis capability. The ISMS

development led to a refinement of the Fast SVM to improve real-time system analysis that resulted

in a program suitable for PC operation. That program is now known as the Battle Damage Estimator

6
(BDE). The BDE takes weapon impact information produced by the FSVM and relates it to

component, system, and mission impact in both a documented listing and pictorial display relating

to failed capabilities within their proper location in the profiled hull form. The BDE is rapidly

nearing adequate detail and sophistication to support a true vulnerability analysis of a particular

design as it relates to primary damage. The BDE has preliminary inputs supporting some secondary

damage spread effects currently related to fire spread, crew casualties, and directly related flooding.

With continued effort the BDE has the potential to support the damage analysis necessary to

accommodate the needs of vulnerability analysis. The military worth analysis approach would still

require fiscal analysis to adequately assess the true warfighting value of vulnerability reduction.

In September 1990, the U.S. Navy co-sponsored a technical workshop with the American

Defense Preparedness Association (ADPA) Combat Survivability Division, Ship Section. The theme

of the workshop was Survivability Assessment Methodologies, with emphasis on ship vulnerability

reduction and damage recoverability. The following were the workshop objectives:

(1) Examine current assessment methodologies and techniques,

(2) Evaluate how well vulnerability and damage recoverability are addressed in the ship and

system design process, and

(3) Identify proposed improvements that can and should be made in assessment methods and

tools.

The a-day workshop result drew five principal conclusions as follows:

(1)

(2)

There is no formal, documented assessment process which provides quantifiable,

recognized, and accepted assessments of survivability during the ship design process.

The requirements for the Cost and Operational Effectiveness Analysis (COEA) (DOD INST

5000.2) place increased emphasis on the need for organizational guidance and policy for

7
(3)

(4)

(5)

survivability assessment; however, there is a lack of an organized procedural structure and

survivability assessment policy with the Navy to guide the Navy technical community.

Computer methods and programs are nonstandard and inadequate to provide the needed

assessment tools for total ship survivability. This inadequacy is further burdened by the

inability to establish data linkages between the various assessment programs.

Total ship survivability assessment requires consideration of the full spectrum of features

involving both susceptibility and vulnerability in order to converge to a balanced

survivability design Current assessment procedures, techniques, and tools do not fully

provide the integration required to achieve that objective.

Mechanisms need to be improved to encourage and afford greater opportunity for

communication and interface among members of the survivability community.

During the workshop, awareness of the forthcoming DOD INST 5000.2 governing “Defense

Acquisition Management Policies and Procedures” resulted in increasing emphasis on the assessment

process, particularly relative to the Cost and Operational Effectiveness Analysis (COEA). Following

the workshop in February, OSD published the 5000 series of acquisition directives. The

implementation of these new acquisitions resulted in two additional activities. The first was that

NAVSEA asked for formalization of the Navy/ADPA Survivability Assessment Methodology

Report, Since I had participated in the workshop, I was tasked to finalize the report. I completed

that report in June 1992 with the following recommendations submitted to NAVSEA:

(1)

(2)

Methodology and Process: Develop a directive and implement a formal survivability

assessment process that will identify design vulnerability relative to specified threats to

support a determination of the ability to meet operational requirements.

Survivability Policy: Establish

assessment requirements policy.

an organizational structure and guiding survivability

8
(3)

(4)

(5)

Computers and Assessment Programs: Provide standards and guidance for computer to

computer data transfer communication requirements necessary to improve assessment

efficiency.

Assessment Requirements: Continue to develop more effective, fully integrated assessment

tools and processes that will enable the assessment of the total ship design over the full

spectrum of survivability.

Organizational Interface and Communications: Develop an effective means of conducting

COEA for total ship survivability.

I am not aware of any NAVSEA activity that would result in implementing those recommendations

to date.

The second activity following promulgation of the DOD INST 5000.2 was OSD’s LFWzE OfTice

asking me to support the LFTdzE effort through the Institute for Defense Analyses (IDA). This

involved development of a program to conduct an LIT&E process in support of ship design analysis.

That participation resulted in development of a process that is believed to be the most equitable

approach to assessment methodology to achieve LFT&E requirements, short of firing a live weapon

at a ship. The LlT8zE Assessment process consists of four elements:

(1) Component, systems, and full-scale ship tests conducted under research and development

program as design specification proof of technology tests.

(2) Surrogate tests to evaluate design to include armor proof, full-, and sub-scale ship section

tests

(3) Damage scenario-based engineering analysis of specific weapons impacts.
(4) Demonstrating the ability of a full-up ship and crew to combat simulated damage from threat

weapons and continue to fight.

The results of the four component tests are combined to form an LFT&E of the total system. To

date, this system appears to be the most executable approach to achieving the LFT&E objectives and

supporting the ship design community’s needs. The SWBDE computer-supported analysis would

be utilized in appropriate areas of all four components,

Biographical Sketch

CPT Barr is ffom West Palm Beach, FL> where he enlisted in the U.S. Navy, March 195I. His

enlisted service includes tours at the Recruit Training Center, San Diego, CA, Damage Control

Training Center, Treasure Island, San Francisco, CA, USS PRAIRIE (AD-15); Instructor Duty at

Camp Elliott Retraining Command, San Diego, CA, and USS GRAPPLE (ARS-7), where Captain

Barr served as a Chief Damage Controlman until commissioned a Limited Duty OfJicer in October

1961.

Upon completing the LDO course at the O@cer C’andi&te School, Newport, RI, in I962,

CPTBarr was assigned to USS CABILDO (LSD-16) as Damage Control Assistant and Ballasting

Oficer. During the tour in CABILDO, he augmented to unrestricted line, then was assigned to CIC’

Training School atNAS, Glynco, GA, prior to proceeding to USS WALLER (DD-466) as Operations

Oficer in July 196.5. In March 1967, CPTBarr took command of USSROCKVILLE (EPCER-851),

an underwater research ship, homeported at Little Creek, VA. In June 1968, he reported to the Fleet

Training Center, Norfolk, VA, where he served as Director of Navigation and Leadership Training

School until October 1970, at which time he attended the Naval Gunfire Support School, followed

by an assignment with the 3rd Marine Division, Okinawa, Japan, as the Sta$fNaval Gunfire O#icer.

In April 1972, CPTBarr was assigned to the Naval Safety Center’s Surface Ship Directorate as

Destroyer Safety Program Analyst and Head of the Safety Information Division. He served as

Executive Ofice, USS HALEAKALA (AE-25) in the Paci$c Fleet from Jantuuy I975 until October

I976. He was then assigned to the Atlantic Fleet Weapons Training Facility where he served as the

Live Ordnance Air to Ground and Ship Gunfire Range Ofice at Vieques Island, Puerto Rico, from

December I976 to July 1978. In November 1978, he took command of USS PLYMOUTH ROCK

(LSD-29) where he served as Commanding Ofticer until December 1980. He served as Executive

Oflcer of the USS SAIP~fiom February I98I to January IP83. He was then assigned to DCNO

Surface Warfare in the Pentagon as Head of the Ship Safety and Survivability O$fice from March

1983 to January 1990. Following his February I990 retirement, CPT Barr established the

consultant service, Ship Survivability Technologies, andhas continued to provide support to improve

ship design vulnerability reduction efforts.

10
CPT Barr attended Palm Beach High School prior to entering the Navy and while in service

attended Old Dominion University at Norfolk, VA,

His awards include the Legion of Merit., Meritorious Service Medal with Bronze Star, Navy

Commendation Me&l with Bronze Star, Navy Achievement Medal with Bronze Star, Meritorious

Unit Citation, the Battle EfJiciency E, Good Conduct Medal with two Bronze Stars, National Defense

Medal with one Bronze Star, Korean Service Medal, Armed Forces Expeditionary Me&l with

second award, Humanitarian Service Medal with Bronze Star, Republic of Korea Presidential Unit

Citation, and the United Nations Service Medal.

CPT Barr is married to the former Inu Kathryn Cache’ of Alexandria, VA.

11
3. Qn the History of Vullnerability/Lethality Analysis

by Roland 6. Bemier

Vulnerability and lethality are opposite aspects of the interaction between military targets and

the munitions designed to defeat them. Modem analysis originated in the mid- 1940s. It evolved as

a process of definition and quantification in ever-increasing detail. A necessary starting point is clear

definition of target defeat (i.e., kill or damage). Many such levels of degradation in function and/or

mission have been defined and standardized to suit various target-munition encounters-for

example, K, A, B, and C kills for aircraft, K, F, and M kills for tanks; among others. Some standard

kills were defined as time-dependent, others as mission-peculiar, and still others to quantify repair

time. In general, most V/L analyses presume detection and hit of the target.

Historically, the study and application of V/L principles appear to have lagged behind the design

and development of military materiel by one or two decades. Aircraft and armored vehicles were

introduced in the 192Os, but systematic V/L analysis and application were not considered seriously

until the 1940s. Sirnihuly, the helicopter was deployed in Korea in the early 195Os, vulnerability was

analyzed seriously in the late ‘50s and early ‘60s for Vietnam, and vulnerability reduction became

an influential design factor in the new helicopters for the 1970s. Vulnerability reduction is now a

requirement in the early design of all military materiel. Concurrently the design of lethality into new

munitions has become increasingly more formalized and sophisticated.

Formal V/L analysis essentially started with the Gptimum Caliber Program at APG in the

mid-‘40s. When World War II ended, the (new) Department of the Air Force found itself with

hundreds of war-weary aircraft. Many of these (fighters and bombers) were flown to APG. Funds

and personnel were provided for the dual purposes of analyzing vulnerability and developing aircraft

(and antiaircraft) munitions. Selected sections/components of the aircraft were penetrated by

selected bullets, shell, and/or shell fragments, and the damage was described and assessed by aircraft

specialists. Standard damage categories (i.e., KK, K, A, B, C, D, E) were defined for the assessment

12
._

methodology. Firings were conducted against running engines, aircraft structures, and cockpits,

actual and/or simulated. Against fuel, air-stream was simulated by means of an operating slave ship.

These aircraft firings were complemented by more controlled test firings against components such

as fuel cells, flight controls, and hydraulics and against materials such as metal alloys, armor,

transparencies, etc.

Early V/L development of databases and methodology (in the 1940s) originated with aircraft

targets and antiaircraft munitions. But parallel developments soon appeared for other military

material and munitions (e.g., armored tanks, trucks, ships, as well as nonmilitary targets, buildings,

bridges, etc.). Increasingly sophisticated V/L analysis even included personnel (at least males).

Fundamentally, methodology consists of combining size factors (i.e., measured presented areas

and empirically determined probability factors for various components, projectiles [threats], and

defined kills of interest). The basic unit of V/L was (and continues to be) vulnerable area (A,),

simply defined as the product of presented area (A$ and kill (damage) probability (Pk). In general,

total Pk may be the product of various constituent Pk factors (e.g., probability of penetration,

probability of leak, probability of ignition, probability of fire propagation, probability of a functional

or mission kill, et al.). A large variety of such PLs have now been accumulated in computerized data

banks for various combinations of components, mechanical/physical systems, attacking munitions,

and desired forms of damage/kill. When suitable Pks are not already available, they are derived from

firings against materials, components, subsystems, systems, mock-ups, whole targets, static and/or

dynamic, engineering analyses, and even from combat damage data when it is available.

Component and/or total presented areas are either measured or calculated one way or another

from blueprints, photographs, models, projections, computerized target descriptions, and even from

actual hardware (when practical). Probably the first models to be used (early 1940s) were the black

plastic models originally designed for WW II aircraft identification training. In the mid-‘40s (and

later), elaborate wood (balsa) and plastic models with color-coded components and systems were

designed and built specifically for V/L analysis. These were photographed from various angles;

35-mm slides were then projected on a ground glass screen for actual measurements of desired

13
component areas. With the advent of the computer age, the whole process has been mechanized.

Computerized target descriptions became possible to account for masking of components by other

invulnerable and/or vulnerable components and/or structure. Note that vulnerable areas and

presented areas are usually additive. Historically, the evolution of V/E analysis was driven by the

development of ordnance materiel-sometimes new targets, sometimes new threats, and sometimes

both. Near the end of WW II, the proximity (VT) fuze was a most important development for

antiaircraft and other artillery because it greatly increased probability of hit. Such shell were

developed in sizes from 180 mm down to 40 mm and considered (but found impractical) down to

20 mm. While direct hits were capable of immediate kills, usually kills were achieved from single

and/or multiple hits by small fragments down to one gram or even less. Such extremes in threats

required vastly different analyses, both for input damage data and for methodology.

Structure represents the largest component of an-craft, and many other targets, but structural

members are generally not vulnerable to nonexplosive shell, bullets, and fragments. Monocoque and

semi-monocoque structures are employed in modem aircraft and some other targets which are

vulnerable to internal blast from shell larger than 20 mm. A notable exception was the B-l 7 Flying

Fortress structure, which was geodetic. Early damage tests included a WW II German high-capacity

30 mm. Most small rocket warheads are capable of structure kills by internal blast. Conversely,

external blast structure kills require much larger warheads generally from guided missiles. Other

components/systems subject to kill/damage by penetration include fuel, propulsion, controls,

armament, and personnel; all of which are possible to defeat by bullets and/or fragments, sometimes

very small in size/weight.

The aircraft appeared as a military target during WW I primarily because of its fuel tanks. In the

1920s came self-sealing tanks (e.g., the German Heinkel) and all the major U.S. rubber

manufacturers. These were effective against the inert bullets-O.30 cal. and 0.50 cal., ball and armor

piercing. Shortly thereafter, incendiary (and armor-piercing-incendiary [API]) bullets were

developed. Such machine gun bullets included incendiary mix in the nose, and functioned (flashed)

upon impact. Sensitivity depends upon striking velocity, the thickness of material impacted, and the

obliquity of strike. For safe handling, sensitivity had to be compromised. For V/L analysis, data on

14
probability of function (i.e., sensitivity data) had to be developed parametrically by empirical firings.

However, ultimate sensitivity required a fuze, which in turn required projectiles at least as large as

20 mm. The high-explosive-incendiary (HEI) shell is commonly used today in 20- to 40-mm aircraft

and antiaircraft cannon. While these shell kill primarily through fuel fire, their blast and

fragmentation are also effective against personnel, controls, engines, and small structures

(e.g., helicopter rotor blades).

The earliest fuel tanks for aircraft and other vehicles were sheet metal-aluminum alloy or thin

steel-very prone to rupture and leakage from projectile perforations. Self-sealing cells have

reduced this hazard, but metal and nonsealing bladders continue to be employed in many applications

(e.g. trucks, aircraft external tanks, et al.). Some fuel fire kills can result from ullage (vaporspace)

explosions, but in general fuel fires do not ignite inside or outside the tanks. Ignition and fire

propagation normally occur in voids between the fuel cell wall and the external skin/structure.

Hence, external tanks and integral tanks, even nonsealing bladder or metal tanks, are not prone to

kill by fire. And, in some designs fire prevention has been achieved by filling voids and spaces with

lightweight plastic foams.

Fuel type also affects fire vulnerability; diesel and kerosene (P-1) are less flammable than

gasoline and the wide-cut jet fuels (JP-3 and JP-4). Experiments have demonstrated that fires still

occur at high altitudes (i.e., over 50,000 ft), but such fires appear less damaging.

Fuel lines/hoses of all types also pose fire problems, especially high-pressure lines. Conversely,

suction fuel systems/components are not prone to leak (or fire) from projectile damage

(i.e., penetration, perforation or even severance). Hydraulic fluid poses another fire hazard,

especially when under high pressures; however, nonflammable hydraulic fluid is available.

Lubricating oil is combustible, but usually it is not readily ignitable by projectile sparks and flashes;

fuel-oil coolers are a notable exception.

15
Fuel kills are also possible without fiie or explosions (e.g., fuel depletion), which can be avoided

by design (e.g., multiple redundant tanks and/or feeds). Also, completely full tanks are prone to

hydrodynamic rum damage, which can cause tank rupture and sometimes even structural kill.

Fuel fires are readily ignited by single HEI shell at any striking velocity and by single API and

INC bullets at sufficient striking velocities. Ignition by inert steel fragments is also possible at very

high striking velocities. Bullets and shell are launched at velocities of 1,000 to 3,000 fps, but shell

warhead fragments are launched at 2,000 to 10,000 fps. At striking velocities of 5,000 fps or more

on aluminum alloy, vaporific flashes can occur, suffkient for fuel ignition, and sometimes even

sufficient to delaminate some types of structure materials like honeycombs. To achieve

hypervelocities experimentally, controlled fragmentation shell were designed as well as

hypervelocity two-stage light-gas (helium) launchers.

While kills by fire and other means can be achieved by single shot/fragment strikes, most kills

during WW II and before probably resulted from compounding multiple hits, where one hit caused

leakage, and ignition occurred from another hit(s) or from an on-board ignition source.

Analysis of accident and combat damage revealed that crash fires were the most frequent cause

of personnel fatalities, especially for helicopters. This led to the development of crashworthy fuel

systems including structures, tank material, hoses and fittings, which were applied for Vietnam and

to all new helicopters since. Note that fuel fire experimental analysis occurred in the late 1940s and

the 1950s; applications of fire prevention concepts began in the 1960s and have continued since.

Instantaneous fire detectors and lightweight fire suppressors and extinguishers continue to be

developed and applied.

By far, fuel represents the largest source of fire/explosion and loss, but other systems/materials

can also contribute, such as on-board munitions and, in particular, the explosives and propellants in

machine gun and cannon magazines, roclcet, and missile warheads, not to mention logistic loads in

transport ground and air vehicles.

16
The evolution of V/L analysis also covered many dynamic systems and components, especially

reciprocating and turbojet engines and their accessory shafts, gear boxes, gears, bearings, pumps,

et al. In general the heavy reciprocating air-cooled engines were found much tougher than their

contemporary liquid-cooled engines and the modem turbo jet engines. The supply of W II aircraft

and trucks provided targets for dynamic controlled damage studies and firing tests against ,

reciprocating engines. A major finding was their resistance to oil-starvation. Oil-starvation tests

were also conducted on helicopter transmissions. In general, bearings were found more vumerable

than gears. The reciprocating engine testing was conducted during the late 1940s; transmission and

other oil-starvation testing came later in the 1950s.

Turbo machinery vulnerability testing involved #both large turbojets and small turboshaft

helicopter engines. Static and dynamic testing was conducted against centrifugal and axial

compressors and turbines with shrouded and unshrouded blading. Combustor testing involved hole

size effects on thrust. Prototype engines were made available for damage tests, and such testing

continues as sacrificial engines become available. Firing ranges and test vehicles continue to be

improved.

Perhaps the most critical components/system involved controls--especially flight controls on

air vehicles. These involved mechanical, hydraulic, and electrical systems and their small

components (e.g., cables, pulleys, bell-cranks, push-pull rods, torque tubes, as well as hydraulic

lines, pumps, and accumulators and also electronic components as technology progressed from the

1930s to the present).

Detailed wound ballistic and human engineering data has been incorporated into V/L analysis

of air and ground vehicles since the 1940s as the state-of-the-art advanced.

V/L analysis also influenced the development of armor of all types from quilted nylon body

armor through heavy protection against large armor-piercing projectiles including antitank

shaped-charge penetrators. Early concepts involved titanium alloys as well as USMC Doron-a

loosely bonded fiberglass laminate in the 1930s. Before modem lightweight armor became

17
available, tipping plates and over arrangements were improvised in H-21 cockpits and other aircraft

to protect against 0.30-cal. and 7.62~mm bullets in Vietnam in the early 1960s. The development

of ceramic-faced composites was initiated by the need for lightweight armor. Aluminum oxide,

boron carbide, and other ceramic tiles were bonded to Doron or nylon fiber-reinforced plastics for

armor against small caliber armor-piercing and API bullets on seats, and critical components.

Modem technology provided Kevlar to replace fiberglass and nylon for ultralightweight armor

protection.

While modem technology frequently served to reduce vulnerability, more often it tended to

increase vulnerability by decreasing weight and/or increasing performance and sophistication. As

a result, continual improvement of V/L analysis has been required to keep pace with ordnance

evolution.

Biographical Sketch

Roland Bemier received his B.S. porn St. Michael’s College, Winooski Park, VT, in January

194.5. Additional courses were also completed at The Johns Hopkins University (194.5-1948) and

the Ballistic Institute (University of Delaware) (1948-1949).

From January I945 until I979, he was employed at BRL, APG, MD. Since 1948, he pioneered

research and development in lethality and vulnerability, vulnerability reduction, and survivability.

These efforts involved experimental testing and early development of methodology including actual

applications to aircraft design. Since retirement from the BRL (1979), he has functioned as a

technical consultant to various DA and DOD agencies directly, as well as to supporting industries,

such as the SURV’CE Engineering Company (Aberdeen, MD). Early research concerned aircraft

fuel fires, hypewelocity impact, test facility development, and related testing.

In the 1950s and I96Os, his primary effort was dedicated to support the integration of

survivability into current and future Army aircraft. Career progress included Chief of the

Experimental Test Section of the Aircraf Weapons and Vulnerability Branch 1964-l 970, to Chief

of the Vulnerability Reduction Branch 1970-1976, to Chief of the Aerial Targets Branch 1976-1979

(retirement). Local recognition included the Robert H. Kent Award (1973) and membership in the

BRL Fellows. In 1966 and again in 1979, the BRL Vulnerability Team received the Department of

the Army Research and Development Award for Technical Achievement.

Within DA, Bernier was consulted by numerous agencies and Project Managers and served on

the Source Selection Boards for LOH, Hm, DIVAD, et al., including UTTAS and AAH, which

culminated in the Black Hawk and Apache helicopters. Similar service was also provided to the

18
USAF and USN (e.g., AMST). At the tri-Service level, in 1971 he assisted in the formation of the

Joint Technical Coordinating Group for Aircraft Survivability (JTCGIAS), where he served as the

AMC alternate Principal Member for numerous years.

Internationally, he contributed to AGARD, NATO, and TTCP working groups in survivability.

In 1962, he participated in an ARPA team to South Vietnam, actually installing crew armor in

deployed helicopters and other aircraf. Subsequently, he organized the collection of combat

damage and casualty data. Documentation and analysis of such data formed the basis for the

introduction and justi@ation of vulnerability reduction features in the design of new aircraf.

Throughout the years, the expertise of the BRL team was thoroughly utilized and appreciated

by DOD agencies and industry. In testimony, no less than 40 letters of commendationlappreciation

were received from the project managers (e.g., Aircraft Survivability [PMASE]), professional

societies (e.g., MORS, SAE), major aircrafi companies, and their supporting hardware

manufacturers. Among these were the Sikorsky Division of United Technology; the Vertol Division

of Boeing Aircraft Co.; Textron Bell Helicopter; McDonnell AIC Co. (including the MH designers,

Hughes Tool Co.); Lockheed (Georgia); General Electric (Lynn Mass. Aircraf Engine Division),

General Dynamics (Fort Worth); Goodyear Aerospace; FMC Corporation; and the Denver

Research Institute, among others. Not least are appreciation letters from the Deputy Under

Secretary of the Army for Operations Research, and the Presidential Science Advisory Committee

(PSAC).

Mr. Bernier passed away in December 1996.

19
4. Reflections Related to Assessment of the Vulnerability

of Armored Combat Vehicles and

the Lethality of Antiarmor Munitions:

The Last Two-Thirds of the First Fifteen Years

[A Meandering Tale of Unverified

Remembrances of an Aged Analyst, Once of BRL]

by Davidson C. Hardison

Thank you for the kind introduction. And thank you even more for the invitation to be here

among friends of so many years.. After all, I have been “retired” for 8 yr now. It is nice to be

permitted to participate in occasions such as today.

The truth is that, in retirement, I have absolutely no pressing calls on my time. Therefore, I am

free to take part in activities, such as those of today, any time I please. My remarks today are in the

form of a tale. Its title is “Reflections Related to Assessment of the Vulnerability of Armored

Combat Vehicles and the Lethality of Antiarmor Munitions: The Last Two-Thirds of the First

15 yr.” Its subtitle is “A Meandering Tale of Unverified Remembrances of an Aged Analyst, Once

of BRL.” Its filename is “BRL9.25.92.”

To my mind, BRJ_, armored vehicle vulnerability/lethality work spans some 45 yr, more or less.

My tale concerns program years 5-15, or, using a different calendar, 1954-1964. I tell you at the

outset that the sequential ordering of my remembrances have not been verified by document review.

Let a historian do that. For me, the marvel of the aged brain is that it recalls that, not that it

occasionally loses track of when. And besides, in retirement, one is free to put on his shoes and then

his socks, in just that order, if he wishes to do so!

My tale is one of activities and persons, myself included. In Biblical terms, it begins about 40 yr

and 40 days ago when I first arrived at the BRL in August 1952 as the Korean War was approaching

its end. As the Chief of the Ordnance Engineering Laboratory, Herb Weiss was busy publishing at

20
least one technical report every month, and expanding his workforce. As one among numerous

others, my application for employment had been accepted.

Pull of energy, enthusiasm, apprehension, and expectations, I was met by Dick Peterson, Floyd

Hill, Jerry Zeller, Andy Benvenuto, Bill Gholston, Al Vincent, Gene Williams, Sid Wise, George

Scott, and a couple of others who welcomed me and told me that I would be working in the Combat

Analysis Section of the Tank Branch.

To that moment, I had never seen a tank. But, soon, I was supposed to know of their tactical

employment, gunnery procedures, fire control, accuracy, rate of fire, armament, logistic support, and

vulnerability.

Dick Peterson, Chief of the Combat Analysis Section, was my first boss. I-Ie, and his boss, Floyd

Hill, were brainy men who were aheady keenly interested in tank tactical operations. This resulted

in my first assignment being to retrieve and digest all of the After-Action reports of tank battalions

_-

used in NW Europe during WW II. The months I spent examining and analyzing those primary

source documents were among the most informative of my extended sojourn in the wilderness of

operations analysis. To this day, I find my fundamental operational instincts driven more than makes

sense by what I mined from those war records.

But soon Ployd had become impatient with the pace of Dick Peterson and Andy Benvenuto in

publishing the results of their analysis of line-of-sight data taken from topo maps. So I was tasked

to help rewrite their report and get it out. Clearly the role of an editor, and not much more. I still

remember my surprise that Floyd decreed that I, in his words, “the principal writer,” would be listed

as a coauthor. Thus my first major lesson learned with the Army was that credit bestowed and credit

due do not always match even closely. Later9 as I received several awards, I saw that they rarely do.

And then came Project Stalk-a large field experiment in which over 13,000 main rounds were

fired at 5 different target ranges by 25 tank crews using 11 different tank, fire control, armament

systems. Floyd Hill had had a strange notion that, in tank battles, the ability to achieve quick kills

21
might be good. So he decided to get some experimental facts. In the Stalk trials, boxes of data were

gathered regarding firing times, and whether hits occurred.

My attempts to understand the meaning of the Project Stalk data were immensely

interesting-mostly because what had happened in the range firings was not, especially as regards

accuracy, even close to pretest expectations. Yet the test facts remained. Indeed, no targets were

hit after the shooting stopped. Determining why the misses had been so frequent, and so

unrespecting of the claims of system advocates, proved to be fun indeed.

Processing the Stalk data was manual and quite time consuming. It was so slow that one had

ample time to ponder underlying causes. To me, it is unclear whether comparable thought would

have occurred had the fast data processing machines of later years been available; I think not.

The point in relating these tangential ditties is to explain that I was not involved in the

vulnerability activities of the Tank Branch my first 3 yr at BRL, and that the tank vulnerability work

had started a couple of years prior to my arrival. So the first one-third of the first 15 yr of BRL work

on the vulnerability of armored vehicles was over before I became acquainted in detail with what was

being done. Therefore, my focus on the later two-thirds of the first 15 yr.

By 1954, Floyd Hill, with his unquenchable thirst for theory-free empirical data, had D&PS do

a sizable number of trials in which tank-fned AP, APC, HVAP, HEAT, and HEP projectiles were

used to attack M4, M5, M24, M26, T29, M46, and T34 tanks. Jack Shanley and Ernest Kirkpatrick

had done hundreds of static firings of HEAT shells against stacks of steel and other armors. Over

in TBL, Joe Regan had made scores of static shots of HEAT shells into armor arrays backed by

Celotex panels to collect behind-armor fragments, but the data were mu& too precious to be

inspected and used by mere mortal analyst.

Elsewhere on campus, Mort Sultanoff made fast photographs, Julie Simon made x-rays, and Lou

Zemow advanced Nobel schemes--even his smaller ideas were dynamite. Off campus, Charlie

Salter at OTAC saw enormous promise in fused silica, Don Kennedy extolled aluminum liners,

22
Perlmutter at RARDE designed successful APDS projectiles, Picatinny fretted over production

tolerances, and (not yet at BRL) Bob Eichelberger, as always thereafter, lamented the absence of

adequate theory and then proceeded to improve it.

Meanwhile Gene Williams, Bill Gholston, Dan G’Neill, and Al Vincent struggled mightily, but

with at most limited success, to make sense of the results of the vumerability firings that Floyd Hill

had commissioned.

What these persons had to work with were blue, ink-besmudged, smelly, firing records. These,

by and large, did a good job of documenting the materials used in the tests, the conditions of the

tests, the observed physical damage to vehicle components, and the vahtes of three metrics called

‘%I,” “F,” and “K” as scored by persons experienced in tank operations and officially designated as .

“Damage Assessors.‘9

At least in the cockles of my aged brain, it is now unclear precisely how the damage assessors

determined the two-digit values of the M, F, and K metrics. Moreover, if memory is correct, it was

equally unclear at a much earlier time. Whether they were unambiguously related to values in some

Standard Damage Assessment List (SDAL) is not now recalled, but your historian surely can fmd

out if he cares to do so.

So the M, F, and K metrics, and possibly an early SDAL, were m-place and hallowed before I

became involved much in vulnerability matters. Exactly what they were supposed to mean was, to

my mind, both ill-conceived and ill-defined, and so they have remained.

Meanwhile, folks such as Morgan Smith, Harry Kostiak, Jerry Dailey, Tom Coyle, Roland

Bemier, Don Mower, Robbie, and others over in the Aircraft Vulnerability Branch reportedly were

well along in understanding the vulnerability of flying machines, thanks in no small measure to the

work begun mostly by Art Stein during the late ‘40s and early ‘50s. Hopefully, Art will later share

some memories of his pioneering efforts. And Joe Sperrazzo had already overseen his definitive

work in the field of wound ballistics. No more 58 ft-lb; hereafter wound ballisticians would worship

23
MV3’2, and incredible polynomials, and personnel casualty predictions thereafter would be

time-tagged and mission-dependent.

It was fascinating back then to sit, to pretend to be thinking, and to watch the tank vulnerability

analysts work over the large blueprints of a tank spread to, and beyond, full coverage of a drafting

table. Much of their time was spent in trying to figure out what the tank was really like at some

particular point of interest-what was the armor thickness, armor obliquity, and into what

compartment might residual jet, or projectile fragments, or spall, impinge. The conversations were

endless, priceless, and costly. An uninvolved listener sometimes had unasked questions regarding

the ultimate accuracy of the process which he viewed to be mostly S&P. Here S&P is used not as

the abbreviation for Standard and Poor of financial matters, but as the short name of the Stare and

Ponder tank vulnerability assessment method that was used in the early-mid 1950s.

The major issues of substance were the vulnerability of the just-developed M41, M48, and T43

tanks, and the lethality of our Al?, APC, and HEAT projectiles when used to attack the T34, T54, _-

and JSIU tanks. On the other side, there was the vulnerability of Soviet tanks, and the lethality of

their lOO- and 122~mm projectiles against our tanks.

The emphasis definitely was more on “getting the numbers,” that is the M, F, and K “kill

probabilities,” than on practical measures to increase the survivability of our tanks or on feasible

means to increase the lethality of our antiarmor munitions. Perhaps these early steps toward

improvements in measuring the capabilities of existing things had to come first, but then, even as

much later, it seemed wrong to allow it to be the principal objective. Surely the goal had to be

increased survivability and increased lethality of our stuff, not just improved measurements of the

capabilities of existing systems conceived by others. Some, I not included, were bothered about a

potential conflict if one tried to be both impartial assessor and improvement instigator. Others, I

included, judged good materiel to be paramount and found the concerns about conflicts of interests

to be both revealing and insulting.

24
Notice that I just used the words “kill probabilities,” not the more correct ones of “average loss

of function.” That was deliberate to illustrate the point that, even in the early days, there was sloppy

thinking as what the metrics really were and that, even then, the metrics were applied in largely

inapplicable ways.

Up to this time, and perhaps we are now up to about 1955, there was essentially no use of

computers in the study of vulnerability of armored vehicles. The calculations, to the extent the

assessments were not subjective, were all manual; the tools were blue print, slide rule, pencil,

columnar pad, and desk calculator.

In fact, there was no accepted systematic scheme for generalizing the results of the firing records,

and no methodical way for applying their implications to other rounds or other targets. At least in

retrospect, in seems that the usual practice had two steps: (1) infer the fraction of the presented area

of the target that would be perforated by a particular round under selected attack conditions and,

(2) somehow or other, mostly the method of S&P mentioned earlier, estimate the consequence of

damage to exterior and interior components. For convenience in making the estimates, the interior

components were grouped into several more or less homogeneous “compartments” such as fuel,

ammunition, engine, crew compartment, etc. Yes, those were the halcyon days when tanks, not tank

armor programs, were compartmented!

By about this time, the Vulnerability Section had let a contract with AAI, Inc., to fabricate

wire-frame and exterior iconic models of the M47, M48, T43, and JSIII tanks at a scale of about

1: 12. These physical models were conceived to be helpful, when used as a matched pair of

wire-frame and exterior view, for visualization of the components that would be insulted from

particular attacks. AAI did its work fine, and the models were delivered, so far as I recall, on

schedule. But analysts soon found them to be not helpful at all. I believe that the models were never

once used. They remained as curios for years-one more idea that had earlier seemed promising but

that turned out to be not worthwhile. And they had been constructed for four target vehicles when

one would have been sufficient to reveal their lack of worth.

25
Meanwhile, the folks in the Aircraft Vulnerability Branch were justly exhibiting pride that they

knew all that was to be known about the vulnerability of flying machines, and apparently of other

aspects of air warfare as well. Their prewar estimates of the exchange rates between F-86 and

MIG- 15 in air-to-air combat were reportedly shown in the Korean War to be unbelievably exact. So

the early work of Stein, Weiss, Smith, et al. had already paid off, even if it was a little hard to figure

out just how.

And by this time, Kirkpatrick and Shanley were in the glass business in a really big way. It had

turned out that, within limits here of interest, the unit price of custom melts of glass was very close

to the reciprocal of the amount purchased. So Kirkpatrick had ordered tons of glass blocks of

multiple sizes and shapes-he just could not resist the bargain.

Most of these glass blocks eventually wound up in surplus stores. There they saturated the

bookend market east of the Mississippi River for years. But, before they could be declared surplus,

these glass blocks had to be properly accounted, stored, and protected.

The glass blocks had been delivered in cardboard cartons of, say, 6 cubic feet each with metal

bands surrounding the packages in two planes. This packaging in cardboard cartons eased the

handling of the blocks but, exposed to the elements on Spesutia Island, it was not long before the

metal bands began to rust, and the cardboard boxes lost their look of freshness. Moreover, it was

not easy to mow between the stacked boxes so unsightly grass prospered-altogether a most untidy

range.

Nothing would do but that these cartons of glass be stored properly in transport containers, those

ubiquitous 8 x 8 x 10 I3 metal boxes. Of course, these metal containers also rusted. So, to ensure

their longevity, they all were given several coats of paint-paint outside of metal containers outside

of metal bands outside of cardboard boxes outside of blocks of glass, the only impervious material

present. It would have made more sense to build a glass igloo containing the metal boxes containing

the bands around cardboard boxes in which the cans of paint might have been stored. But what made

sense did not matter, what looked good did! Point: don’t believe old timers when they tell you that

26
things were sensible in the “good old days.” Truth is, there was nonsense then just as now and, at

least arguably, in comparable amounts.

As regards tank perforability by ICE projectiles, the five pieces of information treated as essential

were target armor thickness, armor obliquity, a ballistic limit vs. T/D curve for the projectile type,

projectile diameter, and projectile velocity at impact. But, even then, it did seem that projectiles

made of hard dense materials, such as tungsten carbide, did quite well, and that long projectiles such

as the fin-stabilized “Arrow,” on occasion, did better than comparable diameter short projectiles of

the same material, especially on the rare occasions when they happened to hit with small yaw. So

already, the potential advantages, and delivery challenges, of high UD KE rounds were apparent,

even if the measures were crude. For HEAT, only three data were needed: armor thickness, armor

obliquity, and Pen vs. Standoff. If one but understood the application of these, and could ahnost read

a drawing, she, albeit mis-titled, was a journeyman vulnerability analyst.

For KE projectiles, the main focus was on perforability, and with considerable justification. Up

until that time, with the low I/D steel projectiles impacting at modest velocities, it had required a

large diameter shot to perforate the thickest armors on tanks. If perforation occurred, the level of

behind-armor damage was so impressive that precision of measurement was comparatively

unimportant, or so it was believed. But for HEAT, a similar argument did not hold, and

behind-armor damage was at issue from the outset. Moreover, exterior components, not themselves

much hurt by small HEAT shells, often resulted in the HEAT warheads being several feet from the

main armor when warhead detonation occurred. Understandably, improved penetration at long

standoff (i.e., precisely where the poor quality shaped charges then in service were deficient) clearly

was an important need, but one not reflected in official Requirements of the time.

By 1956 or so, Floyd Hill and Ernest Kirkpatrick and Jack Shanley and Gene Williams and other

early beacons had repaired to enriched callings elsewhere. Gerry Zeller was by now a section chief,

and his main challenge was to “make sense out of the Firing Records” and “figure out how to make

vulnerability assessments.” Gerry was not quick, or slick, or clever, or-to my knowledge+ever

very wrong. He was intuitive, plodding, careful, peerless with a French curve, patient to a fault,

27
28

possessed of excellent analytical instincts, and amaster of approximations. He always first imagined

the way output data ought to relate broadly to input data, and then he looked for evidence supporting

or contradicting his intuition. He perhaps too highly respected first moments; he always recognized,

but often set aside, the implications of higher ones.

Gerry tried, with validity that others having insights different from his have later questioned, to

roughly correlate average behind-armor damage to exit hole diameter for both KE and HEAT rounds,

depending on which compartments the perforating rounds insulted. His scatter diagrams showed

enormous scatter, but he thought he saw patterns. He saved as grossly predictive the trends he

thought he saw, and set aside the unaccounted residuals. By so doing, he both advanced the then

current practices and left ample room for later persons having more advanced adding machines to

improve the accounting. But be not deceived: what you do now, though better, is what he did before

you.

WhiIe speaking of Gerry Zeller’s work, let me next recall a few details of the birth of the

Tripartite Standard Tank Targets, later, the NATO Standard Tank Targets. Gerry and I, with our

colleagues Bill Snarr of Canada and Ronnie Shepherd of England, had learned the power of

international means to accomplish matters that we would have been unable to pull off unilaterally

at home. By the mid-late ‘50s it had become plain that tank and antitank munitions, being designed

to meet “requirements,” at minimum cost, were not what they should have been, and in ways that

were fmable but only if the “requirements” were more meaningfully stated. But then, as later,

“requirements” were not our responsibility. So the basic challenge was somehow to arrogate de

facto control in the absence of responsibility and authority. The solution was to have the

co-conspirators tasked by the Tripartite users to look at intelligence information and technical

options open to thoughtful future vehicle designers to identify a standard set of testable range targets,

the defeat of which would be taken as evidence of sufficiency of antitank munitions. That way,

others would continue to state the requirements; we would just assist a little by telling them what

they surely must have meant.
So, in the summer of 1956, or some other good year thereabouts, we repaired to Ottawa for the

seance. Each of us came with initial views, and they were not close to being the same. For what I

now recall as two solid weeks, the examinations continued. The discussions remain in my memory

to this day as my best example of several serious persons trying very hard to get as close as possible

to an admitted unknowable. But it was all for a proper end, and it paid off.

After the fortnight of discussion, we finally reached agreements, only to discover that no one had

been designated the note-taker, and that the many turns in the serpentine path of logic were not easily

reconstructed. In much fatigue, and some despair, Ronnie Shepherd suggested the report be very

short, that it say “We thought long and hard about the assigned task and concluded that: (1) o . .‘9

And so we did. Perhaps nothing speeded acceptance of the proposed targets more than the paucity

of documentation of the rationale of their derivation, another example of “The Law of Sausages:

Consumers Who Observe Production No Longer Are Consumers.” Was it not Henry Ford, who

when found at the site of an early auto accident with a young lady, not his wife, refused to comment,

saying only “Never apologize, never explain”?

If there is anyone here who has not heard of these early Standard Tank Targets, he probably is

in the wrong meeting. They were important drivers in the design of .Westem world antitank

munitions for at least two decades-too long, of course, but with substantial benefits for years.

After only a decade of work in the tank vulnerability business, it had become reasonably clear

at BRL that one really needed to describe each potential target vehicle in such a manner that the

description could be used routinely whatever the attacking projectile. The person most responsible

for doing just that was Dick Hoyt. Dick was quick, slick, clever, and to my personal knowledge,

sometimes very wrong. He had a frontiersman% way of thinking not then found often, now rare

indeed, a willingness to fell a forest one tree at a time. His proposed approach was to select a

particular impact point and attack direction and then to describe the shotline all the way through the

vehicle, noting the compartments traversed and defining all the stuff that would be encountered by,

say, a nondeflected jet of great length.

29
A critic quickly pointed out that vehicles are far from homogeneous. If other impact points

and/or attack direction be selected, the shot-line materials almost certainly would be different. Dick

agreed, and asked how many samples would suffice (i.e., what grid size would make one

comfortable).

Thinking that the effort involved would dissuade him from such a labor-intensive approach, it

took about 10 s for one to suggest a cell size of 4 inn, with one point to be selected uniformly at

random within each cell. Dick’s response was to calculate that, for seven directions of attack, there

would be about 20,000 cells involved, that an industrious analyst should be able to characterize an

average of about 30 cells per hour or 330 per working day. So one should be able to describe a target

vehicle in a mere 2 mo of uninterrupted work.

And then, by golly, he did just that! Others checked cells selected at random and confirmed his

data. The data files of these 20,000 or so cells per vehicle immediately suggested use of ORDVAC

as the bookkeeper. Moreover, comparatively simple algorithms were written to combine the armor

penetrating characteristics of attacking projectiles, the target description, and the results of Zeller’s

behind-armor damage correlations. Howard Ege, surely more than anyone else, was responsible for

this computer application, and for perfecting the ability to generate enormous stacks of printouts

showing what the computer said would happen if a particular round were to hit a particular target

at a particular location under defined conditions. And, of course, integration over these specific

points was an almost trivial computer task, given the distributions to be used to weight them. So,

to Howard Ege, more than to others, belongs the credit for introduction of the relentless discipline

intrinsic to the algorithms of the computer-based methods used, with many major improvements to

be sure, until today.

Howard also, with some not-so-subtle prodding, came up with an innovative scheme of using

the three-color alpha-numeric printers then available to construct a slightly distorted color graphic

showing the vulnerability of a vehicle depending on strike location for attack conditions fixed.

Essentially, the scheme exploited the fact that line spacing on the printer was, or could be made,

close to the width of two print characters. For each cell, the average functional loss, correct to two

30
places, was printed in a color depending on its magnitude, at a position on the page corresponding

to its location on the vehicle. What resulted was a first-generation vulnerability color map. It was

quite helpful for briefing analysis procedures and results, and even more so for data quality control..

One simply could not find the errors in tabulated data; it was much easier to see them in pictures.

Once Dick Hoyt had described one target tsnk, he knew quite precisely what it should cost to hire

commercial firms to do as many others as we wished to pay for. As I recall, firms such as Denver

Research Institute were happy to have the money-it was not much-and we were happy to have

the tank description data in this highly usable form. I admit we were even happier to not have to do

the knuckle work. Altogether, a good deal for all parties.

Dick Hoyt went on in later years to introduce the use of combinations of standard geometric

shapes to represent the armor and interior components of armored vehicles. That process clearly is

in the lineage of current methods, but it will not here be discussed.

By this time, vulnerability questions were spreading from tanks to other armored vehicles such

as APCs and SP howitzers. In particular, the very small shaped-charge bomblets such as those later

carried in cluster shells and munitions were a hot topic. Fortunately, a tall, gangly, fast-thinking,

slow-talking young man from Mississippi named Bob Kirby had returned to BRL after completion

of an active-duty sabbatical in the Army. As I recall matters, it fell to Bob, more than to others, to

do the testing, adapt the analysis methods, and analyze the lethality of these small bomblets and to

estimate the vulnerability of targets to attacks by them. His work, for example, was the first to show

what happens when the tiny jets from smalI shaped charges and massive pistons of tank-sized diesel

engines attack each other.

In the end, Picatinny chose bomblet sizes that probably were other than best. Whether that be

correct or not correct, they had advice from the antipersonnel lethal area technicians of Abe Golub’s

Artillery Branch of BRL. But, what the hey, as the lawyers say, you win some and you lose some,

but you get paid for all of them. And, what is more, in our business, you sometimes even get to

know when you are right. Ample rewards, I would say-who could ask for more!

34
As BRL armored vehicle vulnerability numbers and BRL antiarmor lethality numbers became

available in increasing quantities in the Ordnance Corps, and in the Army more generally, they

stimulated endless questions, mostly from advocates of a particular pet rock, as to whether the “ivory

towered scientists” at BRL were even close to right. That was as it should have been. After all,

persons were threatening to make serious system development decisions based on our numbers,

when elsewhere others were making quite different vulnerability/lethality assessments.

For example, at about this time of 1957-58, the French were selling all who would buy them

antitank missiles carrying HEAT warheads of about lQ@mm diameter, and claiming assured defeat

of known and projected tanks. We were favoring ShiIleIagh-sized warheads and saying that their

considerably larger warhead would prove better suited to defeat of future tanks. Englishmen felt

certain the only prudent thing to do was to carry60 lb of HE as did the Australian Malkara and

English Orange William antitank missiles. Incidentally, neither of Her Majesty’s missiles entered

field service, but it was not because they were found too small!

It was in that context of controversy that I, as now seems to have been my habit, exceeded my

authority and at a meeting in London proposed live-fire tests that later became known as the

Tripartite Trials at CARDE. The trials were Tripartite alright, but the U.S. did provide the test

warheads, the target vehicles, the mechanics to repair target vehicles, most of the vulnerability

analyst, and the strawman test plan and the strawman evaluation plan, both of which were

implemented with minor improvements Canada provided the real estate and range support, and the

UK sent a couple of keen analysts, one of whom was Lynn Jones, who later made many

contributions to the UK, NATO, and even to U.S. defense efforts.

These trials proved to be important but, to my mind, not for the reasons many persons later

seemed to think. They did yield much data, but, in perspective, they added little to what was known

at BRL before them. Contrary to what Chicken Little briefers have crowed, they most certainly were

not the first and only “live-fire test” prior to Chicken Little. What the CARDE trials did do was to

force BBL to expose in detail its armored vehicle vulnerability approach, warts and all, for others

to inspect, to question, and to suggest improvements. And they resulted in comparisons of test

32
results with forecasts of them made prior to the shots. So, importantly, they moved the BRL

approach from a fairly closeted laboratory scheme to a far-from-perfect, but broadly understood,

method used widely in Tripartite circles. Thus, from the CARDE trials, the BRL vulnerability

program gained some valuable data, gained some slight improvements in methodology, and gained

major increases in credibility-as much or more, I judged, as one gets from most tests.

At some point in this tale it would have helped to talk of the efforts to find practical means of

defeating shaped-charge jets, of the work to assess the benefits of spall liners, and of the attempts

to build composite-armor hulls and turrets for the ill-fated T95 tank whose development was

terminated in 1958 because of serious problems in design of the hull, chassis, suspension, track,

fire-control, engine, transmission, gun, and ammunition. But those stories, along with the saga of

MBT-70, the beginning of TOW and Dragon and Sheridan, can best await another day when

questions of classification no longer arise.

Besides, this tale has already meandered for too long. I hope that I have minded, or reminded,

.-

you of some of the activities, and a few of the lasting accomplishments, of the last two-thirds of the

first 15 yr of BRL’s armored vehicle lethality/vulnerability work. Subsequent to the time of this tale,

there have been two additional 15-yr periods during which others have advanced the art and, perhaps

even more, the art-work of vulnerability analysis. Persons more familiar with the contributors and

their contributions must spin those yams at later gatherings.

In closing, I want to return to a point made near the beginning-that credit bestowed and credit

due do not always match. When I reflected back on the early years, I thought fast on what was done

and then next on who did it. I concluded it proper to emphasize the contributions of five particular

individuals whose work proved to matter. Let me again mention them and what, to my mind, they

did:

Q Ployd Hill, who, possessing a never-ending conviction in the value of theory-free empirical

data, caused the initial firings that generated the data that begged to be explained.

33
l Gerry Zeller, who succeeded in interpreting the firing data in terms of more-or-less predictable

interaction of a projectile having measurable terminal ballistic properties with a vehicle having

describable target properties.

l Dick Hoyt, who had an inability to recognize that the amount of work involved in preparation

of detailed descriptions of tanks as targets was prohibitive, and who was both able and willing to do

just that, thus demonstrating a workable way to describe tanks as targets and, as important, that

preparation of target descriptions was mainly a matter of commitment, not principle.

0 Howard Ege, who achieved the lasting discipline and production potential resulting from

putting the target description data on the computer and marrying to it projectile terminal ballistics,

to include the results of the target damage work done by Zeller.

l Bob Kirby, for extending the vulnerability assessment envelop to include armored targets other

than tanks and munitions other than antitank munitions.

So far as I know, not one of these five persons ever received any special recognition from OSD,

OSA, HQDA, AMC, the Director, BRL, or their Laboratory Chief. If they did, fine. If not, it was

a mistake. For, according to the remembrances of this Aged Analyst, once of BRL, each of us, in

no small way, is indebted to each of them for what they did. To be sure, others were there then, and

still others have followed. In many cases, their work was good also. But, it is best thought of as “the

same as,” or as “refinements of,” or “different from” that of these five persons of the later two-thirds

of the first 15 yr. Therefore, without hesitation, we-their contemporary or follow-on coworkers

who knew them best-should now share a sustained applause that loudly acclaims that they have our

unsurpassed accolade: superior craftsmen.

I now lead it, and, if you agree with my assessment, I invite you to join.

34
Biographical Sketch

Mr. David C. Hardison received a B.A. in Mathematics ffom the Atlantic Christian College in

1949, an M.A. in Mathematics from Duke University in 1951, and an MS. in International Afsairs

from the George Washington University in 1972. He also received a diploma from the National War

College in 1972.

From 1952 to 1964, he worked as a weapon system analysis in BRL, including a tour as the

Chief of the Armored Systems Branch. He served as Scientific Advisor to the Commanding General

of the U.S. Army Combat Developments Command from 1964 to 1972, and from 1973 to 1975 as

an Analysis Advisor to the Deputy Chief of Stafs, US. Army.

In 1975, he became the Deputy Under Secretary of the Army for Operations Research, and in

1980, he moved to the Department of Defense as the Deputy Under Secretary of Defense, Tactical

Warfare Programs. He returned to the Army as Director of the U.S. Army Concepts Analysis

Agency, and retiredporn that position in 1984. Since then he has been a defense consultant.

Mr. Hardison’s areas of interest include tactical war$are systems, military operations research, ’

and systems analysis.

35
5. Two Turning Points and a Continuing

by Richard E. Kinsler

Improvement

In the mid-1960s, it became apparent that North Vietnam was supporting the war in the South

by moving large quantities of war materiel south along the Ho Chi Minh trail. Since the bulk of this

war materiel was moved by trucks, the study of the vulnerability of trucks became a priority

throughout the DOD. As a result of this priority, the Science of vulnerability estimation for surface

targets progressed rapidly from manual methods, through the early target description techniques and

Parallel-Ray analyses of single-fragment impacts, to the early Combinatorial Geometry target

descriptions and Point-Burst analytical techniques, all of which are the direct ancestors of the

techniques used today.

BRT, was able to obtain approximately 300 medium weight class cargo trucks simply by paying

for their transportation to Aberdeen. Shortly after the arrival of this motor pool of trucks, we

obtained some 400 new and rebuilt engines for the trucks, again for the cost of transportation The

fact that the trucks were being phased out of the inventory had no effect on their value as targets for

study. As it turned out, these older trucks were of the same design generation as the Soviet trucks

which were being targeted along the Ho Chi Minh trail. A maintenance slhop was established in what

is now the main BRL conference room in building 300, and recent graduates from the mechanics

course in the Ordnance School were used to staff the shop until they received their assignments.

One of the early uses of the trucks was to attempt to understand the different ways that trucks lost

the capability of powered movement, and the types of damage that resulted in the loss of this

capability. Analysis, supported by tests, quickly reveal4 that the ignition system, the lubrication

system, and the cooling system were the three systems which most often resulted in complete loss

of powered movement (mobility) of the truck as a result of impact by a small caliber projectile or

a fragment of reasonable (e.g., about 1,000 grams or less) size. Tests also demonstrated that the

time required for a truck to become nonfunctional was repeatable, given loss of the ignition system

36
(immediate loss), or complete loss of the engine lubricant (about IO-15 min), or complete loss of

engine coolant (about 25-30 min). Heavier power train components (e.g., steering components, gear

trains, axles, etc.) tended to fail immediately after damage, or they did not fail within a meaningful

length of time. Based on these test data, the kill criteria for trucks were established as the time

elapsed between the onset of damage and the complete loss of powered movement. The criteria were

defined as:

Kill Level Elapsed Time

ji

. Establishing these kill criteria based on the measured response of the target to a specific class

of damage (e.g., lower engine damage resulting from complete loss of lubricant) as opposed

to a specific type of damage (e.g., a hole in the oil pan) was a turning point in the field of

vulnerability analysis. For the first time, a kill criterion had been established for surface

targets which was founded on an observed, repeatable phenomenon. Easily observed and

readily understood loss of function (powered movement) was the result of physical processes

acting because damage had been sustained by the truck. As a result of defining the kill criteria

for trucks in this manner, the probability of kill calculated in the analysis of trucks was a true

probability that the truck lost all powered movement, rather than suffered some undefined

reduction of capability.

While we, at BRL, were developing kill criteria having some rational basis, and trying to

establish a rationale for criticality analyses, Falcon Research and Development Company of Denver,

CO, was under contract to the Naval Weapons Center (NWC) at China Lake, CA, to develop a

computerized target description of the ZIL-157 truck and to conduct a single-fragment vulnerability

analysis of the truck. BRL and NWC joined forces to conduct a series of analyses of the truck. The

BRL kill criteria were proposed and accepted for use in the study. The NWC contribution to the

37
study was to be the target description and the analysis program, whose output was to be the

vulnerable area of the truck, based on an array of single fragment mass-velocity combinations. The

BFCL contribution was to be the results of the criticality analysis, a set of Pwhs for each of the critical

components and validation of the analytic results, based on our experience from having examined

a lot of fragment-induced damage on trucks.

At that time, a few experimentally derived P,,s existed; however, Ptis for each critical

component did not exist. Neither time nor resources were available to determine Pklhs

experimentally. Therefore, it became necessary to devise some analytical method of developing

consistent and defensible Ptis for all critical components of the truck. Over the next several months,

the basic concept of performing. a miniature vulnerability analysis of each critical component,

examining each of the six cardinal faces of the component from several obliquities, and using

established engineering techniques (modified by test observation) to estimate the size and placement

of the hole required to render the component nonfunctional was established and reduced to practice.

For the first two targets, the m-157 truck and the KrAZ-214 truck, the Pk,s were calculated by

hand. Only later did we feel that we had enough time to develop and de-bug a computer program

to do the arithmetic, thus freeing analysts from the mechanical calculators of the day and moving

them into the computer age.

. Establishment of a method of developing P,,s anaQtically is seen as the second turning point

described in this vignette. Since components are designed by engineers who are trained in the

application of natural laws, it seems to make eminent good sense to have other engineers

“reverse engineer” a component to predict the level of damage required to render the

component nonfunctional and ratio sensitive areas to presented areas to develop a probability

of kill. Developing the component P,s in this manner produces a P, which is a true

probability that the component will cease to function, rather than some measure of component

degradation short of complete loss of function. One of the criticisms leveled at the method

is that only perforation of the component is considered. This criticism is not entirely

warranted, however, it is true that consideration of other damage mechanisms is somewhat

subjective and heavily dependent on the background and expense of the analyst. It remains

38
for current analysts to expand the method to include other damage mechanisms such as shock,

structural deformation, crack propagation, etc. Perforation of components is the primary kill

mechanism observed in full-scale test programs when a damaged target is examined. When

other damage mechanisms have been observed, damaged components typically had also

sustained killing damage from fragment perforation.

Results of the criticality analysis and the P,s were forwarded to Falcon in Denver. This began

the second most interesting phase of the study. Falcon would run the analysis on the large computers

at NWC and air express the resulting case of computer print-out to the Baltimore-Washington

International Airport. We would meet the plane, claim our case of computer print-out, bring it back

to BRL, and spend the next day or so studying the results. There would then be a 2- or 3-hour

telephone conversation with the analyst at NWC. Modifications would be made, the analysis re-run,

and another case of print-out air expressed east. After about three of these cycles, all decided that

the analytical results did not differ too badly from what had been observed in full-scale testing. The

results were then summarized and forwarded for use in the end game analysis.

Only later, when some of the analyses were run at BRL, did we begin to develop a true

appreciation of the magnitude of a single truck analysis. The first analyses that were run on the

computers at BRL were run either at night, or over a weekend, because one single run required the

complete attention of either the BRLESC I or BRLESC Il computer, and all of the operational tape

drives (for both machines) for somewhere between 8 and 10 hr. Initially, the typical analysis would

run to about 95% completion and then drop off of the computer because of tape parity errors.

Naturally, this typically occurred just before the print cycle began, resulting in the loss of all data.

(All available tape drives were being used to store input data, and none was available to store

output.) Later, as disk drives were developed and BRL began to obtain them, we were able to write

to disk and save the first part of the run.

l The third point implied in this vignette is more of a relentless progression around a spiral

curve which begins slowly, but whose radius is ever decreasing, resulting in an ever-sharper

curve. It is the ever-faster increase in the raw computing power and capability of computers.

39
In the mid- 196Os, a component-level analysis of a not-very-complex truck to a single fragment

impact was completed only by utilizing the entire computational power of the largest

computers available (on either the East or the West Coast) for a period of 8-10 hr. The large

matrices necessary for the conduct of the analysis were kept in volatile memory because they

were always changing and it was not practicable to work with them if they were on tape. As

mentioned above, it was not unusual to lose 6 or 7 hr of computational effort because of tape

parity errors. It was the late 1960s and early 1970s before computers had progressed to the

point where it was practicable to begin conducting complete point-burst analyses of a truck

from all azimuth-elevation combinations in a single run, although single burst points and

limited azimuth-elevation combinations had been calculated as the analysis program was

developed and compared with full-scale test results.

The three turning points identified herein are considered premiere in the science of vuhrerability

analysis because they were basically the tip of the arrow in the sense that they were some of the

initial work done as the field was just being established and was in the process of rapid development.

Although the kill criteria established for trucks in the 1960s were based on observed test results, it

is probably time for the community to re-examine the criteria. Truck design has changed over the

last 25-30 yr, as has the additive packages used in lubricants and coolants. It seems reasonable to

assume that these changes have had some effect on the elapsed time required for a truck to lose the

capacity for powered movement after the onset of the damage.

The basic method of analytically developing a probability of kill, given a hit for a critical

component, has not changed over the last 25-30 yr. True, there have been a number of generations

of the “Pwh Program,” but each of these generations has added capability to the computer code,

without altering the basic premise of developing a probability of kill by developing some type of

ratio of component-sensitive area to component presented area. The current efforts to develop the

Pa GEN methodology with its associated database, and somehow assign a level of conj?dence to

the Pwhs plus incorporate rules of thumb for use by analysts, are long overdue. This effort is a giant

step in providing a basis for consistency among all analysts. It is also seen as an outstanding method

of immediately disseminating useful test results to a target audience.

40
The march of progress of computers is known to all, but is probably best appreciated by those

who remember the bad old days when computers were young and did not nearly have the abilities

of even laptop computers today. Conversations with analysts who conducted analyses on those early

computers or who worked to develop the current methods of target description should result in many

interesting war stories.

Biographical Sketch

Mr. Kinder spent the majority of his professional life as a vulnerability analyst in the Sur$ace

Targets Branch of the VulnerabilitylLethality Division of the BRL. He has written or co-written

more than 70 technical reports covering most phases of vulnerability analysis, ranging from the

unconventional attack of conventional targets through the more conventional vulnerability analyses

conducted today.

His practical experience ranges from the design and conduct of large full-scale test programs

through smaller hands-on studies in demolitions research. He also has extensive experience in the

exploitation offoreign materiel.

41
6. Milestones in Modeling the Vulnerability of Military

Personnel to Fragmenting Munitions

William J. Sacco and Wayne S. Copes

This is a short chronicle of milestones in modeling the vulnerability of military personnel to

fragmenting munitions.

6.1 Milestone 1: Current Incapacitation Criteria. Currently used criteria for estimating the

probability of incapacitation from a single fragment wound were published in 1965. The probability

of incapacitating a soldier given a hit by a fragment is modeled as a function of body region, an

infantryman’s tactical role (attack, defense, supply, or reserve) and the time after wounding (30 s,

5 mill, 12 hr).

These criteria are based on a complex set of experiments, assessments by physicians and

experienced combat soldiers, and analyses of the effects of four steel fragments: the 0.85~grain steel

sphere, and the 2.1-, 16-, and 225-g&n steel cubes. The original wound ballistics assessments of

these fragments were conducted during the period 1954-1960 (references 1,2,3,4, and 5).

Criteria development began with fragment firings into animals and excised animal organs. The

resulting data were the basis for relationships between the mass and impact velocity of a fragment

and its velocity retardation and the hole size created in various organs.

Wound Classes (see Table 1 for examples) were established to define the degree of damage to

anatomic structures. Pertinent wound classes vary with the mass and striking velocity of the

fragment being evaluated. For example, the 0.85~grain steel sphere may, for any impact velocity,

be incapable of producing the severe skull fragmentation or depressed skull fracture of wound class

J%

42