Ballistic limit predictions for perforation of aluminium armour plates by rigid nose-pointed projectiles

Masri, Rami; Durban, David

doi:10.1016/j.ijimpeng.2019.05.006

Cited by 16 publications

(10 citation statements)

References 33 publications

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“…The cavity expansion models use the solution of the pressure for steady expansion of a cavity in an infinite medium as the contact pressure experienced by a projectile that penetrates a target. While the assumption of spherical or cylindrical flow fields in the target material during the penetration may be considered a rough approximation to the actual flow field (Yarin et al, 1995;Roisman et al, 1997;Rubin et al, 2016), cavity expansion theories have been widely accepted as a basic physical model underlying perforation and penetration mechanics in metallic materials (Masri, 2016). According to Durban and Masri (2004) and Cohen and Durban (2013a), key to the success of the cavity expansion theories is that they provide simple expressions for critical parameters like the resisting force, the ballistic limit and the penetration depth (e.g.…”

Section: Introductionmentioning

confidence: 99%

Dynamic cylindrical cavity expansion in orthotropic porous ductile materials

Santos

Vaz-Romero

Rodríguez-Martínez

2019

International Journal of Impact Engineering

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This paper investigates the steady-state elastoplastic fields induced by a pressurized cylindrical cavity expanding dynamically in an anisotropic porous medium. For that task, we have developed a theoretical model which: (i) incorporates into the formalism developed by Cohen and Durban (2013b) the effect of plastic anisotropy using the constitutive framework developed by Benzerga and Besson ( 2001) and (ii) uses the artifical viscosity approach developed by Lew et al. (2001) to capture the shock waves that emerge at high cavity expansion velocities. We have shown that while the development of the shock waves is hardly affected by the material anisotropy, the directionality of the plastic properties does have an effect on the elastoplastic fields that evolve near the cavity. The importance of this effect is strongly dependent on the cavity expansion velocity, the initial porosity and the strain hardening of the material. In addition, the theoretical model has been used in conjunction with the Recht and Ipson (1963) formulas to assess the ballistic performance of porous anisotropic targets against high velocity perforation.

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Section: Introductionmentioning

confidence: 99%

Dynamic cylindrical cavity expansion in orthotropic porous ductile materials

Santos

Vaz-Romero

Rodríguez-Martínez

2019

International Journal of Impact Engineering

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“…In this logarithmic formulation the spherical cavitation effective yield stress (𝑌𝑌 𝑐𝑐 𝑆𝑆 ) is shown to play an essential role. Comprehensive comparisons to experimental data in [14][15][16] have shown that the logarithmic formulation of 𝑠𝑠 𝑐𝑐 leads to accurate predictions of ballistic limit velocities, and in [17] it is observed that the accuracy of the analytical predictions is at least comparable to the accuracy of numerical simulation results. In the study [18], four ductile hole enlargement models have been compared for their ability to predict ballistic limits of aluminium plates impacted by 7.62 mm armour piercing bullets (APM2 bullets) at normal incidence.…”

Section: Introductionmentioning

confidence: 93%

“…This definition for ballistically equivalent targets was validated by finite element simulations for aluminium and steel targets in [20] and is discussed in the next section. Here it should be mentioned that the cavitation pressure needed for steady cylindrical cavity expansion under plane-strain conditions [4][5][6][7][8][9][10][11]21] is shown in [15], [17] and [20] to be suitable only for ballistic limit predictions under perforation conditions that are close to plane-strain (ℎ/𝐷𝐷 ≈ 3). However, the logarithmic formulation (3) is shown, by comprehensive comparisons to experimental data [14][15][16][17][18], to be accurate enough for ballistic limit predictions of many target/threat combinations and over a wide range of ℎ/𝐷𝐷 ratios.…”

Section: Logarithmic Formulation Of the Specific Cavitation Energy 𝒔𝒔 𝒄𝒄mentioning

confidence: 99%

“…where ζ and Γ are the well-known Riemann Zeta and Euler Gamma functions, and 𝐹𝐹(𝑛𝑛) ≃ 1/𝑛𝑛 + 0.73𝑛𝑛 for common metals [15]. The definition of 𝑌𝑌 𝑐𝑐 𝑆𝑆 suggests an effective elastic/perfectly-plastic response with the same quasi-static spherical cavitation pressure 𝑝𝑝 𝑐𝑐 𝑆𝑆 (and the same elastic properties 𝐸𝐸 and 𝜈𝜈) as of the actual metal with the true stress-strain curve.…”

Section: 𝜎𝜎(𝜀𝜀) 𝐸𝐸mentioning

confidence: 99%

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The Importance of the Cavitation Effective Yield Stress and the Hole Slenderness Ratio for Accurate Predictions of Ballistic Limit Velocities

Masri

2023

Proceedings of the 9th World Congress on Mechanical, Chemical, and Material Engineering

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Perforation and penetration mechanics research is mostly governed by experimental and numerical investigations while analytical models are less available due to the extremely complicated nature of the subject. Sufficiently thick ductile targets are perforated by rigid, nose-pointed projectiles in a ballistic process whose dominant failure mode is ductile hole enlargement. Several recent studies have shown that for perforation process by ductile hole formation, the specific cavitation energy, which reflects the target material resistance to steady hole expansion, is essential for analytical predictions of ballistic limit velocities. The ballistic limit velocity is the minimum impact speed that is required for complete perforation of a given target by a given projectile. A logarithmic formulation for the specific cavitation energy of metal targets, which is based on the concepts of (spherical cavitation) effective yield stress and hole slenderness ratio, is shown in several recent studies to be very useful for analytical predictions of ballistic limit velocities. The logarithmic formulation for the specific cavitation energy is presented, and the concepts of cavitation effective yield stress and hole slenderness ratio are reviewed and discussed regarding their importance for accurate analytical predictions of ballistic limit velocities. The present article is a review of these two concepts and their usefulness in perforation mechanics.

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“…Dynamic spherical cavity expansion theories have been widely accepted as a basic physical model underlying indentation and penetration mechanics in metallic materials [18,29]. The problem studied is that of a pressurized spherical cavity of instantaneous radius a expanding under self-similar, steadystate conditions in an infinite medium described with the constitutive framework of Section 2.…”

Section: Dynamic Spherical Cavity Expansion Modelmentioning

confidence: 99%

Size effects on the plastic shock formation in steady-state cavity expansion in porous ductile materials

Santos

Rodríguez-Martínez

2021

Mechanics Research Communications

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In this paper, we have studied the hypervelocity expansion of a spherical cavity in an infinite medium modeled with the extension of the porous plasticity criterion of Gurson [23] developed by Chen and Yuan [7] to account for plastic strain gradient induced size effects. Following the self-similar, steady-state solution derived by Cohen and Durban [9] for size-independent porous materials, we have computed the critical cavity expansion velocity which leads to the emergence of plastic shock waves for a wide range of initial void volume fractions and different values of the length scale parameter that controls the effect of size. We have shown that size effects hinder the emergence of plastic shock waves, so that as the length scale parameter increases, the expansion velocity required for the plastic shock to be formed increases. In addition, while porosity favors the formation of plastic shocks, as shown by Cohen and Durban [9], our results indicate that the effect of initial void volume fraction on plastic shock wave formation decreases for size-dependent materials.

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Ballistic limit predictions for perforation of aluminium armour plates by rigid nose-pointed projectiles

Cited by 16 publications

References 33 publications

Dynamic cylindrical cavity expansion in orthotropic porous ductile materials

Dynamic cylindrical cavity expansion in orthotropic porous ductile materials

The Importance of the Cavitation Effective Yield Stress and the Hole Slenderness Ratio for Accurate Predictions of Ballistic Limit Velocities

Size effects on the plastic shock formation in steady-state cavity expansion in porous ductile materials

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