Armor Steel Impacted by Projectiles with Different Nose Shapes – Numerical Modelling

The presented experimental investigation concerns 3 mm thick target plates impacted by strikers with different noses at velocity close to 300 m/s and is conducted to gain an insight into mechanisms of deformation and fracture characteristic for a high strength high hardness armour steel, [1]. Guaranteed by the producer yield strength and ultimate tensile strength of the steel are 1300 MPa and 2200 MPa, and the hardness is within 600 – 640 HB, [2]. Due to impacts, the projectiles and targets, both extracted from the armour steel, are severely deformed and fractured. Numerical simulations of the performed test are carried out using the explicit solver of the finite element software package LS-Dyna R9.0.1. The model used in the simulation implemented through the user material subroutine accounts for a yield function with a non-associated flow rule, a Swift–Voce strain hardening law and Johnson–Cook type of multipliers with the effects of strain rate and temperature. The stress-triaxiality, Lode angle parameter and strain-rate dependent Hosford–Coulomb fracture initiation model is employed to predict a steel failure, [3-4].