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Terminal Ballistics and Impact Physics

Penetration Efficiency as a Function of Target Obliquity and Projectile Pitch

[+] Author and Article Information
Charles E., Jr. Anderson

Engineering Dynamics Department,
Southwest Research Institute,
P.O. Drawer 28510,
San Antonio, TX 78228-0510

Thilo Behner

Fraunhofer Institute Kurzzeitdynamik,
Ernst-Mach-Institut, Eckerstr. 4,
79104 Freiburg, Germany

Volker Hohler

Retired
Fraunhofer Institute Kurzzeitdynamik,
Ernst-Mach-Institut, Eckerstr. 4,
79104 Freiburg, Germany

It is noted that there is little difference between α1 and total yaw for large angles of yaw (that is, α2 is negligible) as is evident by examining Tables 5–7, and as discussed in the Appendix.

Manuscript received June 4, 2012; final manuscript received August 22, 2012; accepted manuscript posted January 9, 2013; published online April 19, 2013. Assoc. Editor: Bo S. G. Janzon.

J. Appl. Mech 80(3), 031801 (Apr 19, 2013) (11 pages) Paper No: JAM-12-1215; doi: 10.1115/1.4023342 History: Received June 04, 2012; Revised August 22, 2012; Accepted January 09, 2013

The influence of pitch (vertical yaw) angle on the penetration reduction of rod projectiles into oblique targets has been investigated for tungsten sinter alloy rods with a blunt nose and L/D = 20. Semi-infinite RHA targets with an obliquity of 30 deg, 45 deg, and 60 deg were impacted at 1650 m/s. The pitch angles were varied between ±90 deg. The strong asymmetric behavior of the target crater is dependent on whether the pitch is positive or negative relative to the obliquity of the target. The experiments provide a good overview of the penetration characteristics of long rods for the whole pitch angle range. The penetration data are described by empirical relations that show good agreement with the experiments.

Copyright © 2013 by ASME
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References

Sorensen, B. R., Kimsey, K. D., Silsby, G. F., Scheffler, D. R., Sherick, T. M., and deRosset, W. S., 1991, “High Velocity Penetration of Steel Targets,” Int. J. Impact Eng., 11(1), pp. 107–119. [CrossRef]
Bjerke, T. W., Silsby, G. F., Scheffler, D. R., and Mudd, R. M., 1992, “Yawed Long-Rod Armor Penetration,” Int. J. Impact Eng., 12(2), pp. 281–292. [CrossRef]
Schmidt, V., 1990, “A Methodology to Evaluate the Effect of Yaw on Penetration,” Proceedings of the 12th International Symposium on Ballistics, San Antonio, TX, October 30-November 1, Vol. 2, pp. 377–383.
Anderson, C. E., Jr., Bless, S. J., Sharron, T. R., and Normandia, M. J., 1998, “Investigation of Yawed Impacts Into a Finite Target,” AIP Conf. Proc., 429, pp. 925–928. [CrossRef]
Goldsmith, W., 1999, “Non-Ideal Projectile Impact on Targets,” Int. J. Impact Eng., 22(2–3), pp. 95–395. [CrossRef]
Bless, S. J., Barber, J. P., Bertke, R. J., and Swift, H. F., 1978, “Penetration Mechanics of Yawed Rods,” Int. J. Eng. Sci., 16(11), pp. 829–834. [CrossRef]
Yaziv, D., Rosenberg, Z., and Riegel, J. P., 1990, “Penetration Capability of Yawed Long Rod Penetrators,” Proceedings of the 12th International Symposium on Ballistics, San Antonio, TX, October 30-November 1, Vol. 3, pp. 202–207.
Yaziv, D., Walker, J. D., and Riegel, J. P., 1992, “Analytical Model of Yawed Penetration in the 0 to 90 Degrees Range,” Proceedings of the 13th International Symposium on Ballistics, Stockholm, June 1–3, Vol. 3, pp. 17–23.
Bukharev, Yu I., and Zhukov, V. I., 1995, “Model of the Penetration of a Metal Barrier by a Rod Projectile With an Angle of Attack,” Combustion, Explosion, and Shock Waves, 31, pp. 362–367. [CrossRef]
Wollmann, E., Hoog, K., Koerber, G., and Wellige, B., 1996, “Endballistische Leistung Angestellter Penetratoren,” Bericht R 110/96, French-German Research Institute (ISL), Saint Louis, France.
Hohler, V., and Behner, Th., 1999, “Influence of the Yaw Angle on the Performance Reduction of Long Rod Projectiles,” Proceedings of the 18th International Symposium on Ballistics, Antonio, TX, November 15–19, Vol. 2, Technomic Publishing Co., Inc., Lancaster, PA, pp. 931–938.
Wollmann, E., Chanteret, P. Y., and Wellige, B., 2001, “Leistung Schlanker Penetratoren Bei Kleiner Bis Mittlerer Anstellung,” Bericht RV 207/2001, French-German Research Institute (ISL), Saint Louis, France.
Roecker, E., and Grabarek, C., 1986, “The Effect of Yaw and Pitch on Long Rod Penetration Into Rolled Homogeneous Armor at Various Obliquities,” Proceedings of the 9th International Symposium on Ballistics, Shrivenham, UK, April 29-May 1, Vol. 2, pp. 467–473.
Cagliostro, D. J., Mandell, D. A., Schwalbe, L. A., Adams, T. D., and Chapyak, E. J., 1990, “MESA 3-D Calculations of Armor Penetration By Projectiles With Combined Obliquity and Yaw,” Int. J. Impact Eng., 10(1–4), pp. 81–92. [CrossRef]
Johnson, G. R., and Cook, W. H., 1993, “Lagrangian EPIC Code Computations for Oblique, Yawed-Rod Impacts Onto Thin-Plate and Spaced-Plate Targets at Various Velocities,” Int. J. Impact Eng., 14(1–4), pp. 373–383. [CrossRef]
Normandia, M. J., 1999, “Eroded Length Model for Yawed Penetrators Impacting Finite Thickness Targets at Normal and Oblique Incidence,” Int. J. Impact Eng., 23(1–10), pp. 663–674. [CrossRef]
Gee, D. J., 2001, “Oblique Plate Perforation by Slender Rod Projectiles,” Proceedings of the 19th International Symposium on Ballistics, Interlaken, Switzerland, May 7–11, Vol. 3, pp. 1123–1132.
Rohr, I., Nahme, H., Thoma, K., and Anderson, C. E., Jr., 2008, “Material Characterisation and Constitutive Modelling of a Tungsten-Sintered Alloy for a Wide Range of Strain Rates,” Int. J. Impact Eng., 35(8), pp. 661–673. [CrossRef]
Anderson, C. E., Jr., and Walker, J. D., 1995, “An Analytic Expression for P/L for WA Long Rods Into Armor Steel,” AIP Conf. Proc., 370, pp. 1135–1138. [CrossRef]
WalkerJ. D., and Anderson, C. E., Jr., 1995, “A Time-Dependent Model for Long-Rod Penetration,” Int. J. Impact Eng., 16(1), pp. 19–48. [CrossRef]

Figures

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Fig. 1

Impact orientations: the rod is rotated in the direction of target obliquity for pitch up, and more normal to the target for pitch down

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Fig. 2

Definitions of αcrit

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Fig. 3

Target positioning: negative target obliquity with positive pitch corresponds to positive target obliquity and negative pitch (see Fig. 1)

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Fig. 4

Definition of penetration depth

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Fig. 5

Normalized penetration depth versus yaw angle for 0 deg obliquity

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Fig. 6

Crater cross sections for negative pitch at 30 deg obliquity. The pointed arrow indicates the rod with pitch angle, tip and orientation with respect to the target.

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Fig. 7

Crater cross sections for positive pitch at 30 deg obliquity. The pointed arrow indicates the rod with pitch angle, tip and orientation with respect to the target.

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Fig. 8

Crater cross sections for negative pitch at 45 deg obliquity. The pointed arrow indicates the rod with pitch angle, tip and orientation with respect to the target.

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Fig. 9

Crater cross sections for positive pitch at 45 deg obliquity. The pointed arrow indicates the rod with pitch angle, tip and orientation with respect to the target.

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Fig. 10

Crater cross sections for negative pitch and without pitch (g) at 60 deg obliquity. The pointed arrow indicates the rod with pitch angle, tip and orientation with respect to the target.

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Fig. 11

Crater cross sections for positive pitch at 60 deg obliquity. The pointed arrow indicates the rod with pitch angle, tip and orientation with respect to the target.

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Fig. 12

Exp. 9839: X-ray photograph (double exposure) of penetrating rod and crater surface (θ = 60 deg, α1 = −88.8 deg)

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Fig. 13

Normalized penetration depth versus pitch for 60 deg obliquity, cosine and sine models

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Fig. 14

Normalized penetration depth versus pitch for 60 deg obliquity, ISL and EMI models

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Fig. 15

Normalized penetration versus pitch for all target obliquities

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Fig. 16

Normalized penetration versus normalized pitch angle

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Fig. 17

Definition of angles

Tables

Errata

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