# IWPDF2023

Effect of Pressure Sensitivity on Hypervelocity Impact Damage

R. Kulkarni ∗ , A. Kamble, P. Tandaiya

Department of Mechanical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India

∗ rohanmk73@gmail.com

Keywords: Hypervelocity impact damage, Drucker-Prager plasticity, pressure sensitivity.

This study focuses on the influence of pressure sensitivity ( β ) in the context of Drucker-Prager (DP) [1] plasticity model on the hypervelocity impact (HVI) performance of a spacecraft shield. The Johnson-Cook (JC) material parameters for pressure insensitive case ( β =0 o ) were chosen to be that of Al6061-T6 Aluminium alloy taken from literature [2]. For the pressure sensitive cases ( β > 0 o ), the DP hardening data was generated in tabular form under pure shear from single element tests conducted at various strain rates and temperatures employing the JC hardening parameters of Al6061-T6 alloy mentioned previously. Thus, the DP model coincides with the JC model under pure shear but differs from the JC model only in terms of pressure sensitivity of yielding. Using the calibrated DP model, single element tests under uniaxial tension and compression were also conducted at various strain rates and temperatures. These tests highlighted the significance of finite pressure sensitivity in terms of tension-compression asymmetry in yield stress across all strain rates and temperatures. Effect of β was not observed in pure shear tests at the same strain rate. HVI simulations were then conducted using the above DP model in ABAQUS/Explicit to investigate the effect of β . An Al6061-T6 spherical projectile was used to strike a target plate, both modeled with three dimensional continuum temperature displacement finite elements of the type C3D8RT in ABAQUS. The impact velocity was taken as 7 km/s perpendicular to the target plate. Simulations were conducted for various values of β =0 o − 30 o . The same Mie-Gruneisen Equation of State, JC ductile failure criterion, and simple tensile cutoff spall failure criterion were employed in all simulations to exclusively investigate the effect of pressure sensitivity parameter.

Figure 1: Contour plots of equivalent plastic strain in the central through-the-thickness cut view of the target for β =0 o ,β =10 o ,β =30 o .

116

Made with FlippingBook Digital Proposal Maker