PSI - Issue 37

Theodosios Stergiou et al. / Procedia Structural Integrity 37 (2022) 250–256 T. Stergiou et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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4. Conclusions In this paper, the effect of projectile ’s nose geometry on the capability of thin non-axisymmetric projectiles to penetrate a thin aluminium plate was assessed by utilising a physically validated finite-element model. By examining the influence of the projectile ’s half-angle on its deceleration, a transition zone was identified where the failure mechanism changes from transverse tearing to stretching. A work expression was developed for the target penetration by identifying the dependency of the projectile deceleration on /ℎ , and allowing to consider the effect of projectile ’s nose geometry on the target resistance. It was concluded that /ℎ was a dominant factor influencing the target ’s local capacity to withstand impact, where higher values were associated with higher target resistance. Additionally, a comparison of the results with previous observations for cases of axisymmetric projectiles determined that the target was less resistant to non-axisymmetric projectiles than to their axisymmetric equivalents. The large projectile width (2.6 times the diameter of an axisymmetric projectile of equal cross-sectional area) was attributed to this decrease and associated with domination of the plane-stress state. References Hallquist JO, 2018. LS-DYNA Keyword User’s Manual, Version R11. California: Livermore Software Technology Corporation. He Q, Xie Z, Xuan H, Hong W., 2016. Ballistic testing and theoretical analysis for perforation mechanism of the fan casing and fragmentation of the released blade. Int J Impact Eng, 91, pp. 80-93. Liu L, Yin S, Luo G, Zhao Z, Chen W., 2021. The influences of projectile material and environmental temperature on the high velocity impact behavior of triaxial braided composites. Appl Sci 11, pp. 3466. Naik D, Sankaran S, Mobasher B, Rajan SD, Pereira JM., 2009. Development of reliable modeling methodologies for fan blade out containment analysis - Part I: Experimental studies. Int J Impact Eng 36 (1). Pereira JM, Revilock DM, Ruggeri CR, Emmerling WC, Altobelli DJ., 2014. Ballistic impact testing of Aluminum 2024 and Titanium 6Al-4V for material model development. J Aerosp Eng 27(3), pp. 456-465. Rosenberg Z, Dekel E., 2020. Terminal ballistics. Stergiou T, Baxevanakis KP, Roy A, Sazhenkov NA, Sh. Nikhamkin M, Silberschmidt V V., 2021. Impact of polyurea-coated metallic targets: Computational framework. Compos Struct 267. Taylor G., 1948. The use of flat-ended projectiles for determining dynamic yield stress I. Theoretical considerations. Proc R Soc London Ser A Math Phys Sci 194(A), pp. 289-299. Thomson WT. 1955. An approximate theory of armor penetration. J Appl Phys, 26(1), pp. 80-82. Woodward RL, Cimpoeru SJ., 1998 A study of the perforation of aluminium laminate targets. Int J Impact Eng 21(3), pp. 117-131. Woodward RL., 1978. The penetration of metal targets by conical projectiles. Int J Mech Sci 20(6), pp. 349-359. Zukas JA., 1990. High Velocity Impact Dynamics.