Stochastic Finite Element Analysis of Composite Body Armor

Abstract

The ballistic impact response of a composite target is an important investigation to assess its reliability for applications to light weight body and vehicle armors. The progressive damage model is developed and implemented in the finite element (FE) code ABAQUS as a user-defined subroutine (VUMAT). A numerical result is obtained using deterministic progressive damage model are validated against existing experimental study in literature. Stochastic finite element analysis (SFEA) is used to study the fiber failure in tension; fiber crushing and in-plane shear failure modes due to ballistic impact. The random variation in material properties and initial velocities are used to determining statistics of stress in the lamina. These are compared to the random strengths in the limit state function and P f surface is obtained by using Gaussian process response surface method (GPRSM). The comparison of P f obtained from Monte Carlo simulation (MCS) and GPRSM. MCS computationally 10 times more expensive in comparison to GPRSM. System P f based on a fault tree analysis is determined to cross and angle ply arrangement in symmetric and anti-symmetric laminates. The P f of symmetric cross ply laminate arrangement for simply supported composite beams are found to be minimum.