Low-Velocity Impact Behavior of Composite Sandwich Panel using Finite Element Modeling

This study presents a comprehensive numerical investigation into the low-velocity impact response of composite sandwich panels featuring three distinct in-plane core configurations: honeycomb, reentrant, and auxetic. Using finite element modeling, the research evaluates the performance of these core architectures in terms of energy absorption capacity, maximum impact force, residual velocity, and progressive damage behavior. The MAT054 material model was employed to accurately simulate the composite face sheets, incorporating the Chang-Chang failure criteria to capture the tensile & compressive failure modes of fiber and matrix, under dynamic loading. The simulations were conducted under varying impact energy levels (20 J, 40 J, and 70 J) to replicate real-world loading conditions and assess the structural integrity of each core design. Results demonstrate that the Reentrant core outperforms all Honeycomb, Auxetic and NOMEX cores across key performance metrics. It exhibited superior energy absorption efficiency, higher peak impact forces, and greater reduction in residual velocity, particularly at mid to high-energy impacts. The inward-collapsing mechanism enabled by its negative Poisson's ratio geometry allows for enhanced stiffness and delayed core collapse, contributing to more stable and progressive energy dissipation below.