A Concise Review on the Interaction 

Between Stress Waves and Cracks 

by Cyril Williams 

ARL-TR-4795 April 2009 

Approved for public release; distribution is unlimited. 
NOTICES 

Disclaimers 

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 21005-5066 

ARL-TR-4795 April 2009 

A Concise Review on the Interaction 

Between Stress Waves and Cracks 

Cyril Williams 

Weapons and Materials Research Directorate, ARL 

Approved for public release; distribution is unlimited. 
ii 

REPORT DOCUMENTATION PAGE Form Approved 

OMB No. 0704-0188

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering 

and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, 

including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson 

Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to 

comply with a collection of information if it does not display a currently valid OMB control number. 

PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 

1. REPORT DATE (DD-MM-YYYY)

April 2009 

2. REPORT TYPE 

Final 

3. DATES COVERED (From - To) 

December 2007–August 2008 

4. TITLE AND SUBTITLE 

A Concise Review of the Interaction Between Stress Waves and Cracks 

5a. CONTRACT NUMBER 

5b. GRANT NUMBER 

5c. PROGRAM ELEMENT NUMBER 

6. AUTHOR(S) 

Cyril Williams 

5d. PROJECT NUMBER 

62618AH80 

5e. TASK NUMBER 

5f. WORK UNIT NUMBER 

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 

U.S. Army Research Laboratory 

ATTN: AMSRD-ARL-WM-TC 

Aberdeen Proving Ground, MD 21005-5066 

8. PERFORMING ORGANIZATION 

 REPORT NUMBER 

ARL-TR-4795 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) 

11. SPONSOR/MONITOR'S REPORT 

 NUMBER(S) 

12. DISTRIBUTION/AVAILABILITY STATEMENT 

Approved for public release; distribution is unlimited. 

13. SUPPLEMENTARY NOTES 

14. ABSTRACT 

A very important concern on the dynamic fracture of engineering materials is the initiation and propagation of cracks which are

subjected to elastic, plastic, or shock waves. However, this review is limited to elastic stress waves for which the theory of

elastodynamics is applicable and thereby minimizing the complexity of the report. Several topics were reviewed for this report

and, although they were limited to elastic stress waves. The following areas of interest were covered: the development of an 

experimental method that uses a disc for loading a half-plane crack with a tensile pulse; the response of a crack under planestrain loading using a plate-impact setup; and, finally, the effects of dilatational (longitudinal) and transverse (shear) waves 

interacting with a crack. 

15. SUBJECT TERMS

stress waves, cracks, dynamic fracture, longitudinal wave, shear wave 

16. SECURITY CLASSIFICATION OF: 

17. LIMITATION 

OF ABSTRACT 

UU 

18. NUMBER 

OF PAGES 

24 

19a. NAME OF RESPONSIBLE PERSON

Cyril Williams 

a. REPORT 

Unclassified

b. ABSTRACT 

Unclassified

c. THIS PAGE 

Unclassified

19b. TELEPHONE NUMBER (Include area code) 

410-278-8753 

Standard Form 298 (Rev. 8/98) 

Prescribed by ANSI Std. Z39.18 
iii 

Contents 

List of Figures iv

1. Introduction 1

2. Theory 2

3. Dynamic Fracture Under Plane Wave Loading 4

4. Stress Wave Radiation From a Crack Tip during Dynamic Loading 9

5. Fracture Generated by a Dilatational Wave 10

6. Extension of a Crack by a Shear Wave 13

7. Concluding Remarks 14

8. References 15

Distribution List 17 
iv 

List of Figures 

Figure 1. Wavefronts for diffraction of a plane wave by a semi-infinite crack. .............................3

Figure 2. (a) Interferometers for measuring surface motion and (b) schematic of 

experimental configuration. .......................................................................................................5

Figure 3. Schematic of (a) the specimen and (b) the flyer plate. ....................................................5

Figure 4. Time-distance diagram. ...................................................................................................6

Figure 5. Cross section of specimens after impact for three different shots. ..................................7

Figure 6. Fractographs obtained for room-temperature conditions; dynamic crack 

propagation. ...............................................................................................................................7

Figure 7. Fractographs obtained for –80 °C conditions; dynamic crack initiation and 

propagation. ...............................................................................................................................8

Figure 8. Stress intensity factor history for a plane square pulse. ..................................................8

Figure 9. Schematic of the experimental configuration. .................................................................9

Figure 10. Experimental and predicted (stationary crack) velocity time profiles at four 

monitoring points. ....................................................................................................................10

Figure 11. Fractograph of ductile crack initiation along the crack front. .....................................10

Figure 12. Dilatational wave incident on a crack. ........................................................................11

Figure 13. Pattern of wavefronts for t > 0. ....................................................................................11

Figure 14. Time rates of change of crack closure energy and surface energy. .............................12

Figure 15. Horizontally polarized shear wave incident on a crack. ..............................................13

Figure 16. Incident, reflected, and diffracted waves. ....................................................................14
1

1. Introduction 

A review on the interaction between stress waves and cracks will be incomplete without a brief 

history on the diffraction of elastic waves. The concept of wave diffraction was discovered in 

the 1600s by Francesco Grimaldi and later explained by Augustin Jean Fresnel in the 1800s. 

Alfred Clebsch was probably the first to employ mathematics in the treatment of diffraction of 

elastic waves by a bounded medium (1). Clebsch’s intent was to study the reflection and 

transmission of light through lenses using wave theory and the complete equations of elasticity to 

calculate the diffraction of elastic waves by a rigid sphere. Even though he failed to establish a 

sound basis for a law of the reflection of light, he did however develop a complete mathematical 

analysis of the scattering of waves as a boundary value problem in elastodynamics. In fact, he 

was the first to study spherical solid harmonics what we now know as Spherical Bessel 

Functions. There have been numerous investigations of the scattering and diffraction of waves 

both theoretically and experimentally and the purpose of this paper is to review few of them. 

Normally, when a body with an existing crack is subjected to surface tractions, the crack may or 

may not propagate depending on the magnitude and rate at which the traction is applied. For low 

rates, classical fracture mechanics may be used to solve the problem in which fracture can be 

predicted once the stress level reaches a critical value. However, for high rates, the crack may 

propagate instantaneously depending on the magnitude of the stress wave and the rate at which it 

is applied. Therefore, the stress field around the crack tip is not in equilibrium and the inertial 

effects cannot be ignored. Unlike classical fracture mechanics which is somewhat well 

established, dynamic fracture mechanics is relatively new when compared to other branches of 

engineering. There are no well established laws governing the behavior of cracks when 

subjected to stress waves, therefore the approach to analyzing such problems is based on 

qualitative reasoning and experience with known solutions to specific problems (2). One 

emerging concept in the treatment of fracture initiation and propagation due to dynamic loading 

is the stress intensity concept. It provides a basis for quantifying the resistance of materials to 

the onset of growth of an existing crack. The basis for this approach can be traced back to the 

Irwin criterion in classical fracture mechanics. This criterion states that the onset of crack 

growth occurs when the stress intensity factor of a material has risen to a critical value called the 

fracture toughness KIC. The experimental determination of KIC can be quite difficult. 

Furthermore, it is worthy to note that traditionally, dynamic fracture experiments are difficult 

and expensive to execute because the equipments involved require a steep learning curve and 

high cost. For this reason, fewer than 100 facilities around the world pursue dynamic fracture 

experiments. 
2

2. Theory 

It is appropriate to begin this section with a brief description on the theory of elastodynamics; 

however, a rigorous treatment of this topic can be found in any introductory book on 

elastodynamics or dynamic fracture. If a body occupying a region R with boundaries ∂R is 

considered, then the complete set of the fundamental field equations governing the motion of a 

homogeneous and isotropic elastic body comprises of the infinitesimal strains, listed in both 

tensorial and indicial notation forms 

  T ( ) 2

ε

1

u u     or   ij u j,i ui, j 2

1

   , (1) 

where u is the deformation. The balance of linear momentum equations also both in tensorial 

and indicial notation forms are 

   ρ ρ σ b u or   ij, j    i i b u , (2) 

where σ, ρ, and b are the stress, mass density, and body force per unit volume respectively. 

Symmetry of the stress component guarantees the balance of angular momentum. Finally, the 

linear stress-strain relation is 

 ( )I 2     tr σ ε or  ij   kk ij  2 ij , (3) 

where δij is kronecker delta, λ and μ are the positive Lame elastic constants. These equations are 

to be satisfied throughout the region occupied by the elastic solid in its initial undeformed 

configuration. When the momentum equation (equation 2) is written in terms of the 

displacement u by substituting equation 1 into equation 3 and the resulting equation substituted 

in equation 2, the Navier equation of motion is obtained as follows: 

   

u u b u            2 . (4) 

Using the vector identity     u u u2 x x     , equation 4 can be rewritten as 

    u u b u    x x    2 2

d s c c , (5)
3

where cd is the irrotational or dilational wave speed, cs is the equivoluminal or shear wave speed, 

and are defined as 



    2

l c and 



 cs  . (6) 

Now, consider the stress wave loading of a semi-infinite crack in an infinite elastic body as 

shown in figure 1. This problem was solved by DeHoop (3) and as shown in the figure, the 

crack was loaded with a normal longitudinal plane pulse whose amplitude is σ0. At the point of 

interaction with the crack, the plane wave is reflected as a plane longitudinal wave 1; but at the 

crack tip, two cylindrical wavefronts 4 and 5 are generated, 5 being longitudinal and 4 being 

shear. Head waves 3 are also generated in order to satisfy the traction free faces of the crack. 

Figure 1. Wavefronts for diffraction of a plane wave 

by a semi-infinite crack. 

Freund (2) has shown that for a semi-infinite stationary crack loaded with a step normal tensile 

wave, the stress intensity factor at the crack tip increases with time as derived in (2) using the 

Wiener-Hopf technique and shown in equation 7. 

1/2

1/2 (1 2 )

(1 )

0 2

( ) t Lct I K 



 



 

  





 , (7) 

where σ0 is the tensile stress, cL is the longitudinal wave speed, and υ is Poisson’s ratio. The 
4

longitudinal wave speed is defined as 

1/ 2

2







 





   

 

L c and ρ is the density of the medium, λ and 

μ are the Lame’s constant. Upon closer inspection of equation 1, it can be noticed that the stress 

intensity factor is directly proportional to time because all the other parameters are constant. 

Under plane strain conditions, the stress intensity factor can be related to the energy release rate 

by the following equation 

   2

2 1 KI E

G   , (8) 

where E is the Young’s modulus for the material. It is generally agreed upon by researchers that 

in order to determine the motion of the crack tip for a given dynamic loading, it is necessary to 

use a fracture criterion for the initiation and propagation of the crack. The three fracture criteria 

generally used are the stress intensity factor model, energy release rate model, and the crack 

velocity model. For both the stress-intensity factor and energy-release rate models, it is assumed 

that the onset of crack initiation and propagation is dependent on two critical values. These 

values are the critical energy release rate and the critical stress intensity factor (fracture 

toughness). 

3. Dynamic Fracture Under Plane Wave Loading 

Ravichandran and Clifton (4) have developed an experimental technique to study the dynamic 

fracture processes that occur under plane strain condition with loading times less than a 

microsecond. The experimental setup is as shown in figure 2a and b. The specimen used for this 

experiment was a disc containing a mid-plane pre-fatigued edge crack and is shown in figure 3 

with the associated flyer plate. Using a gas gun, the thin flyer plate of the same high-strength, 

low-ductility steel (4340 VAR) was launched and impacted the specimen. Upon impact, a 

compressive pulse was generated which propagates through the thickness of the specimen and 

reflects back from the back free surface as a tensile pulse. Figure 4 is a time-distance or 

Lagrangian plot and it shows the propagation of the generated stress wave in both the specimen 

and flyer plate. This plane tensile pulse then loads the crack which in turn foster crack growth 

initiation and propagation. 

The authors used a high-strength, low-ductility steel (4340 VAR) so that the plastic flow in the 

specimen would be minimized and therefore, they were able to interpret the experimental results 

using elastodynamic fracture mechanics. For the experimental results to be valid, the plastic 

flow near the crack tip must be negligible or confined to a small region near the crack tip. 
5

 2 (b) 2 (a) 

Figure 2. (a) Interferometers for measuring surface motion and (b) schematic of experimental 

configuration (4). 

Figure 3. Schematic of (a) the specimen and (b) the 

flyer plate (4). 
6

Figure 4. Time-distance diagram (4). 

During the experiment, the back face of the specimen was monitored using interferometer 

techniques. The interferometer used for their experiments consists of both normal displacement 

interferometer (NDI) and normal velocity interferometer (NVI). The NDI was used to monitor 

the displacement of the back face of the specimen and the NVI to monitor the velocity of the 

back face of the specimen. 

The authors (4) found that the growth in the central region of the specimen was fairly uniform 

and the final segment of the crack path was also usually curved towards the impacted face as 

revealed in figure 5. The authors also pointed out that the final segment may have being affected 

by the cylindrical unloading waves from the lateral boundaries which may arrive at the crack tip 

before crack arrest occurs. A scanning electron microscope was used to study the specimens 

before and after the experiment. It was found that for experiments performed under room 

temperature conditions, there was evidence of void growth and coalescence as shown in figure 6. 

This indicates that the fatigue crack grows in a ductile mode, typical of low to moderate cycle 

fatigue. This implies that the primary fracture mechanism appears to be that of void growth and 

coalescence because there is no observable change in the fracture surfaces for the fatigued region 

and the high rate fracture region. Furthermore, another interesting observation was made by the 
7

Figure 5. Cross section of specimens after impact for three different shots (4). 

Figure 6. Fractographs obtained for room-temperature conditions; dynamic crack 

propagation (4). 

authors for experiments conducted at –80 °C. The fractographs shown in figure 7 for the region 

of initiation and propagation revealed that there was a sharp transition from ductile to cleavage 

fracture mode. The dimpled region on the right side of the top fractograph in figure 7 represents 

the pre-fatigued region and the rest of the fractograph represent the cleavage region emanating 

from dynamic fracture. Therefore, at low temperature crack growth initiation occurs by 

cleavage. 
8

Figure 7. Fractographs obtained for –80 °C conditions; dynamic crack 

initiation and propagation (4). 

Using elastodynamic calculations, Ravichandran and Clifton (4) were able to develop the curve 

shown in figure 8. It shows the relationship between the stress intensity factor and time. It is 

clear that the stress intensity factor is directly proportional to time as mentioned earlier and it can 

be seen from the figure that ‘K’ increases and then decays with time. The authors were able to 

show that the growth time (ta - τ) of the pre-fatigued crack is based on a critical stress intensity 

factor, the fracture toughness (KIC). 

Figure 8. Stress intensity factor history for a plane 

square pulse (4).
9

4. Stress Wave Radiation From a Crack Tip during Dynamic Loading 

Plate impact experiments were conducted by Prakash et al. (5) using pre-fatigued 4340 VAR 

steel specimens to understand the dynamic fracture processes which occur during submicrosecond time scales. The experimental loading configuration was identical to that used by 

Ravichandran and Clifton (4) in which a specimen with a plane crack was loaded with a square 

tensile pulse using plane strain condition as shown in figure 9. Motion of the back face of the 

specimen caused by waves diffracted from the stationary crack and by those emitted by the 

running crack was monitored using a laser interferometer. The velocities measured from 

experiments of the back face of the specimen were in good agreement with those obtained from 

elastodynamics calculations except for the spike shown in figure 10 (located at t*c/H = 0.4) 

which is the crack initiation phase. The spike is not predicted by elastodynamic analysis and as 

mentioned earlier is understood to be related to the onset of crack growth. The results obtained 

by Prakash et al. (5) reinforces the idea that the primary fracture mechanism appears to be that of 

void nucleation, growth, and coalescence which was shown earlier by Ravichandran and Clifton 

(4). Figure 11 is a fractograph which shows the void growth and coalescence after a dynamic 

fracture event. 

Figure 9. Schematic of the experimental configuration (5).
10

Figure 10. Experimental and predicted (stationary crack) 

velocity time profiles at four monitoring points (5). 

Figure 11. Fractograph of ductile crack initiation along the 

crack front (5). 

5. Fracture Generated by a Dilatational Wave 

Achenbach and Nuismer (6) analyzed a Griffith crack in a brittle material with a plane 

longitudinal wave as shown in figures 12 and 13. They ensure that the wavefront is parallel to 

the crack. They investigated both the particle velocity and the normal stress in the vicinity of the 

crack-tip. The authors used a balance of rate of energy to determine the shape of the incident 

pulse. They expressed the rate of energy balance for the wave propagation problem in the form 

shown in equation 9. 
11

Figure 12. Dilatational wave incident on a crack (6). 

Figure 13. Pattern of wavefronts for t > 0 (6). 

dt

dD

dt

dT

dt

dV

dt

dU    , (9) 

where dU/dt is the instantaneous rate of work of the external loads, V and T are the strain and 

kinetic energy and D represents the dissipated energy. Considering a half plane, the power 

balance may then be written as 

dt

dT

dt

dV

dt

dE

dt

dU c

2

1

2

1

2

1

2

1

   , (10) 
12

where dEc/dt is the instantaneous rate of work of the surface tractions. It can be easily concluded 

from equations 9 and 10 that 

dt

dE

dt

dD c   . (11) 

Equation 11 then establishes the power balance condition for crack propagation. In figure 14, 

the crack closure energy and the dissipation term are plotted vs. the dimensionless parameter bc 

(b is a constant and c is the crack speed). From the figure, it is clearly evident that dEc/dt is zero 

at bc=0 and bc=some x value, implying vanishing crack speeds and crack speeds equal to that of 

the Rayleigh surface waves respectively. Crack speeds above that of the Rayleigh surface waves 

require energy generation rather than energy absorption at the crack tip. 

Figure 14. Time rates of change of crack closure energy and surface energy (6). 

Achenbach and Nuismer (6) used the notion that if energy is dissipated only as fracture energy 

and if the specific fracture energy is a constant, then the crack propagation at an instantaneous 

velocity occurs only if the stress has a square-root singularity at the wavefront of the incident 

wave. Furthermore, the authors deduced from the above criterion that a step wave cannot induce 

instantaneous crack propagation, irrespective of the jump in stress. This is because dEc/dt and

dD/dt are linear in time and constant respectively and cannot possibly supply enough energy 

instantaneously to create new free surface as shown in figure 14. However, if a crack is 

subjected to a step-stress wave of large enough magnitude, crack propagation at an instantaneous 

velocity should be expected and this is contrary to the previous statement. This may motivate 

the use of a time-dependent dissipation term dD/dt through assumed time-dependence of the 

specific surface energy or through some plasticity mechanism. 
13

6. Extension of a Crack by a Shear Wave 

Achenbach (7) analyzed a problem similar to the one in the previous section, however, the load 

in this case was shear as oppose to dilatational. Shown in figures 15 and 16 is the stress-wave 

loading configuration and the resulting diffraction pattern respectively. The purpose of the 

analytical investigation was to determine the conditions for crack propagation upon diffraction of 

an incident shear wave by an existing crack. Just as in the case for the dilatational wave, 

Achenbach analyzed the problem in two parts. The particle velocity behind the crack tip was 

first analyzed and then the shear stress ahead of the crack tip. Achenbach found that the crack in 

an undisturbed brittle elastic medium can be driven to propagate instantaneously only if the shear 

stress shows a square root singularity at the wavefront. Achenbach also found that if the shear 

stress at the wavefront is finite, the crack may propagate a short time after it has interacted with 

the wave. Furthermore, for a pre-stressed material, crack propagation may be generated instantly 

by a smooth wave if the stress intensity factor of the pre-stressed material is large enough. 

Figure 15. Horizontally polarized shear wave incident on a crack (7). 
14

Figure 16. Incident, reflected, and diffracted waves (7). 

7. Concluding Remarks 

Although the fundamentals concerning the interaction of stress waves and cracks in dynamic 

fracture mechanics have been developed to a reasonable extent; however, when compared to 

other fields of study in engineering such as classical fracture mechanics, dynamic fracture is said 

to be in its infancy. The development of dynamic fracture is seriously impeded by experimental 

measurement techniques because of its inherent time dependency. Because of this inherent time 

dependency, it is extremely difficult to measure the quantities of interest without interfering with 

the process being observed. New experimental techniques are being developed to address such 

problems. For further information on elastodynamics and dynamic fracture mechanics, the 

reader is encouraged to review references 8–16. 
15

8. References 

1. Mow, C.; Pao, Y. The Diffraction of Elastic Waves and Dynamic Stress Concentrations; 

Report R-482-PR; The Rand Corporation: Santa Monica, CA, 1971. 

2. Freund, L. B. Crack Propagation in an Elastic Solid Subjected to General Loading: III. 

Stress Wave Loading. J. of the Mech. and Physics of Solids 1973, 21 47. 

3. DeHoop, A. T. Representation Theorems for the Displacement in an Elastic Solid and their 

Application to Elastodynamic Diffraction Theory. D.Sc. Thesis, Technische Hogeschool: 

Delft, Holland, 1958. 

4. Ravichandran, G.; Clifton, R. J. Dynamic Fracture Under Plane Wave Loading. Int. J. of 

Fracture 1989, 40, 344–349. 

5. Prakash, V.; Freund, L. B.; Clifton, R. J. Stress Wave Radiation from a Crack Tip during 

Dynamic Initiation. J. of Applied Mech. 1992, 59, 356–365. 

6. Achenbach, J. D.; Nuismer, R. Fracture Generated by a Dilational Wave. Int. J. of Fracture 

Mech. 1971, 7 (1), 77–88. 

7. Achenbach, J. D. Extension of a Crack by a Shear Wave. J. of Appld. Mathematics and 

Physics 1971, 21 (6), 887–900. 

8. Achenbach, J. D. Wave Propagation in Elastic Solids; Elsevier: Amsterdam, The 

Netherlands, 1975. 

9. Freund, L. B. Dynamic Fracture Mechanics; Cambridge University Press: Cambridge, UK, 

1998. 

10. Ravi-Chandar, K.; Knauss, W. G. An Experimental Investigation Into Dynamic Fracture: I. 

Crack Initiation and Arrest. Int. J. of Fracture 1984, 25, 247–262. 

11. Ravi-Chandar, K.; Knauss, W. G. An Experimental Investigation Into Dynamic Fracture: II. 

Microstructural Aspects. Int. J. of Fracture 1984, 26, 65–80. 

12. Ravi-Chandar, K.; Knauss, W. G. Dynamic Crack Tip Stresses Under Stress Wave Loading: 

A Comparison of Theory and Experiment. Int. J. of Fracture 1982, 20, 209–222. 

13. Achenbach, J. D.; Keer, L. M.; Mendelsohn, D. A. Elastodynamic Analysis of an Edge 

Crack. J. of Appld. Mech. 1980, 47, 551–556. 
16

14. Chang, S. J. Diffraction of Plane Dilatational Waves by a Finite Crack. J. of Mech. and 

Appld. Mathematic 1971, XXIV, 423–440. 

15. Achenbach, J. D.; Khetan, R. P. Kinking of a Crack Under Dynamic Loading Conditions. J. 

of Elasticity 1979, 9, 113–129. 

16. Ramulu, M.; Kobayashi, A. S.; Kang, B. S. J.; Barker, D. B. Further Studies on Dynamic 

Crack Branching. Experimental Mechanism 1983, 431–437. 
NO. OF 

COPIES ORGANIZATION 

17

 1 DEFENSE TECHNICAL 

 (PDF INFORMATION CTR 

 only) DTIC OCA 

 8725 JOHN J KINGMAN RD 

 STE 0944 

 FORT BELVOIR VA 22060-6218 

 1 DIRECTOR 

 US ARMY RESEARCH LAB 

 IMNE ALC HRR 

 2800 POWDER MILL RD 

 ADELPHI MD 20783-1197 

 1 DIRECTOR 

 US ARMY RESEARCH LAB 

 AMSRD ARL CI OK TL 

 2800 POWDER MILL RD 

 ADELPHI MD 20783-1197 

 1 DIRECTOR 

 US ARMY RESEARCH LAB 

 AMSRD ARL CI OK PE 

 2800 POWDER MILL RD 

 ADELPHI MD 20783-1197 

ABERDEEN PROVING GROUND

 1 DIR USARL 

 AMSRD ARL CI OK TP (BLDG 4600) 
NO. OF NO. OF 

COPIES ORGANIZATION COPIES ORGANIZATION

18

ABERDEEN PROVING GROUND

 55 DIR USARL 

 AMSRD ARL WM 

 J SMITH 

 AMSRD ARL WM MB 

 W DEROSSET 

 AMSRD ARL WM T 

 P BAKER 

 AMSRD ARL WM TA 

 W GOOCH 

 M BURKINS 

 T HAVEL 

 T JONES 

 M KEELE 

 D KLEPONIS 

 B LEAVY 

 J RUNYEON 

 K STOFFEL 

 S SCHOENFELD 

 AMSRD ARL WM TB 

 R BANTON 

 N ELDREDGE 

 R EHLERS 

 R GUPTA 

 AMSRD ARL WM TC 

 G BOYCE 

 N BRUCHEY 

 T BJERKE 

 T DIGLIANI 

 T EHLERS 

 T FARRAND 

 M FERMEN-COKER 

 E KENNEDY 

 K KIMSEY 

 L MAGNESS 

 R MUDD 

 R PHILLABAUM 

 S SCHRAML 

 D SCHEFFLER 

 B SORENSEN 

 R SUMMERS 

 S SEGLETES 

 A TANK 

 C WILLIAMS (10 CPS) 

 W WALTERS 

 AMSRD ARL WM TD 

 A BJERKE 

 D CASEM 

 J CLAYTON 

 N GNIAZDOWSKI 

 M GREENFIELD 

 R KRAFT 

 B LOVE 

 E RAPACKI 

 AMSRD ARL SL 

 R COATES