Experimental and numerical assessment of high-velocity impact behavior of syntactic foam core sandwich structures

Abstract In this study, the high-velocity impact behavior of new designed sandwich structures with syntactic foam core and FML skins is investigated by experimental and numerical approaches. An appropriate numerical model is developed in order to modelling of the impact behavior of sandwich structures using the finite element software ABAQUS/Explicit. In this model, two VUMAT subroutine are presented to simulate the constitutive models of GFRP composite and syntactic foam. In addition, a multiscale finite element procedure is employed to predict the effective mechanical properties of woven orthogonal composite from known properties of its constituents. This procedure is implemented the numerical homogenization techniques using Python scripting. High-velocity impact tests are performed using a gas-gun and steel conical projectiles to assess the accuracy of the numerical model. To this end, the numerical model is validated by comparing the high-velocity impact behavior of sandwich structures to that obtained from experimental study and demonstrated to be effective and accurate. The presented numerical model can predict the residual velocity and perforation energy with 88.8% and 97.4% accuracies, respectively. Then the validated numerical model is employed to investigate the effect of projectile shape, projectile mass, and stacking sequence of skins on the impact behavior of the sandwich structure.