Perpustakaan Digital ITB

This study presents a numerical study on the dynamic penetration behavior of 3D re-entrant auxetic honeycomb structures subjected to direct impact using a Hopkinson bar. The research aims to develop and validate a finite element model capable of replicating experimental conditions reported in previous studies. Simulations were conducted in LS-Dyna using polymer-based auxetic specimens manufactured via stereolithography, with three variations of cell strut thickness (1.5 mm, 2.0 mm, and 2.5 mm) tested under three impact velocities (5 m/s, 10 m/s, and 15 m/s). The results show that increasing strut thickness enhances impact resistance by reducing penetration depth and increasing peak force. Comparisons between elasto-plastic and elasto-plastic with damage models revealed consistent auxetic behavior, including effective stress localization and improved energy absorption. The findings confirm that auxetic geometries provide superior load distribution and resilience against catastrophic failure, highlighting their potential for lightweight, impact-resistant applications in aerospace and related engineering fields.