The Dynamic Response of Aluminum Alloy Plates Subjected to Multiple-Fragment Impacts Under Pre-Tensile Loading: A Numerical Study

This study presents an innovative numerical investigation into the synergistic effects of pre-tensile loading and multi-fragment hypervelocity impacts on thin-walled 7075-T6 aluminum alloy structures, addressing a critical gap in aircraft survivability design under realistic combat conditions. Utilizing an advanced finite element framework with stress dynamic relaxation preloading, the established model was rigorously validated against experimental gas-gun impact data, achieving less than 11% deviation in residual velocity. Distinct from prior single-impact studies, our work pioneers a systematic multi-parameter analysis encompassing multiple pre-stress levels, circumferential/linear fragment distributions, velocity gradients, and geometries. The findings of this parametric study establish a linkage between dynamic penetration mechanics and operational airframe stresses, offering guidelines for damage-tolerant design optimization in aircraft structures.