The effect of impactor shape on low velocity impact behavior of cylindrical sandwich structures with trapeozidal core

The aim of this study is to investigate the impact performance of a cylindrical sandwich structure with Trapeozidal core under different geometries of impactors using the finite element method. The effects of impactor shape, facesheets thickness and impact point on peak contact force, absorbed energy efficiency, maximum displacement and damage deformation are investigated. Progressive damage analysis based on the Hashin damage criterion was performed using MAT 54 material model in LS DYNA finite element program for low velocity simulations. The impact behavior was investigated by creating a Cohesive Zone Model (CZM) based on bilinear traction-separation law while providing the connection between the core structure and its surfaces. At the end of the study, it was determined that the contact force values at P2 were higher than P1. Peak force variation values for cylinder, cone and sphere tipped impactors at P1 and P2 points were 43.5%, 132.3% and 62.2%, respectively. Core support has a significant effect on the contact force. The peak force value and energy absorption efficiency value obtained with the Cone impactor are higher than the others. For all three impactors, it was determined that the largest and dominant damage type was matrix damage.