Practical formulae for predicting the ballistic limit velocity of armour perforation by ductile hole growth

• Published in: International journal of impact engineering Vol. 167; p. 104219
• Main Author: Masri, Rami
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.09.2022; Elsevier BV
• Subjects: Aluminum; Analytical modelling; Ballistic limit velocity; Cavitation; Ductile hole formation; Finite element method; Hardening; Ludwik-Voce hardening; Mathematical analysis; Mathematical models; Monolithic target; Perforation; Perforation mechanics; Plane strain; Slenderness ratio; Perforation mechanics; Ballistic limit velocity; Analytical modelling; Monolithic target; Ludwik-Voce hardening; Ductile hole formation
• ISSN: 0734-743X; 1879-3509
• DOI: 10.1016/j.ijimpeng.2022.104219

•Useful summary of available formulae for specific cavitation energy is presented•New formulae for targets with a combined Ludwik-Voce hardening law are derived•Experimental data, finite element numerical results and analytical predictions are compared•Analytical predictions are at least comparable to the numerical simulation results•Plane-strain, cavitation models are less accurate than the analytical models Previous comparisons to vast amount of experimental data have shown that the specific cavitation energy of target material, which takes into account the hole slenderness ratio effect, is essential in predicting ballistic limit velocity for perforation by ductile hole growth. In the present study, a concise summary of available formulae for the specific cavitation energy of monolithic targets is provided in a practical and accessible way. New analytical expressions are derived for specific cavitation energies and effective yield stresses of targets with linear-hardening response and combined (multi-terms) Ludwik-Voce hardening rule, with Ludwik and Voce laws as special cases. Four (and in two cases five) analytical predictions of ballistic limit velocities, which consider the hole slenderness ratio effect, are compared with experimental data for perforation of aluminium and steel targets. The accuracy of these analytical predictions is compared, in several Tables and Figures, with predictions by cylindrical plane-strain, cavitation model and finite element numerical simulations.