Experimental and numerical investigation of energy absorption in honeycomb structures based on lozenge grid unit cells under various loading angles

• The energy absorption characteristics of lattice structures using Lozenge grid unit cells made from glass fiber reinforced PLA is analyzed. • The mechanical behavior and the damage model were simulated, revealing a good correlation between numerical and experimental results. • Lozenge grid structures at 0 and 90° showed the highest energy absorption capacity, while 45° showed the least. • Heat treatment was performed at 70 °C and the energy absorption capacity of the recovered structure was investigated. The present study aims to numerically and experimentally analyze the energy absorption characteristics of honeycomb structures using Lozenge grid unit cells made from continuous glass fibers reinforced polylactic acid (PLA). The design and load-bearing capability of the Lozenge grid was also examined under different orientations angles. The composite grids were also subjected to heat treatment after the tests, at 70 °C, in order to measure its effect on the energy absorption capacity. The Lozenge grid specimens were additively manufactured using fused filament fabrication. The mechanical properties and failure models were described using the VUSDFLD subroutine in order to simulate the Lozenge structure under quasi-static compressive load. The results revealed a good correlation between the numerical and the experimental values. Moreover, Lozenge grid unit cells based structures at 0 or 90° was found with the highest energy absorption capacity. Meanwhile, the least energy absorption was seen at 45°. Overall, the structures had much higher energy absorption capacity at angles closer to 0 and 90°. Outcomes from this work is aimed toward understanding the damage tolerance of Lozenge lattices, and hence the reliability of such new emerging lightweight structures.