Experimental and numerical studies on quasi‐static behavior of sandwich composites with nano clay modified Kevlar facesheets and aluminum honeycomb core

Abstract This study investigates the influence of nano clay reinforcement on the mechanical behavior of Kevlar/epoxy composite laminates and sandwich structures subjected to quasi‐static punch shear loading. Three types of composite face sheets were fabricated using hand lay‐up technique: Kevlar/epoxy neat, 0.5, and 1 wt. % of nano clay. The mechanical properties of these composites were characterized through compression, shear, and tensile tests. Sandwich structures were then constructed using the fabricated face sheets and an aluminum honeycomb core. Quasi‐static punch shear tests were performed on the composite laminates and sandwich specimens using hemispherical impactors. Numerical simulations of the punch shear tests were conducted in LS‐Dyna, employing appropriate material models and contact definitions for the constituent materials. Furthermore, to further investigate the failure mechanisms, scanning electron microscopy (SEM) analysis was conducted on the fractured Kevlar/epoxy composite plate specimens. The comparison between the experimental outcomes and numerical data demonstrated a strong correspondence, indicating consistency between the two methodologies. In conclusion, the incorporation of 0.5 wt. % nano clay into the Kevlar/epoxy composite resulted in a 5.09% increase in shear strength and an 11.29% increase in maximum reaction force. The study provides insights into the effect of nano clay reinforcement on the punch shear resistance and energy absorption capabilities of Kevlar/epoxy composites and sandwich structures. Highlights Proper alignment of the nano clay within the epoxy was achieved. The most efficient rate of nano clay was observed to be 0.5% by weight. The mechanical properties of nano clay‐containing composites were improved. Quasi‐static punch shear tests were performed numerically and experimentally. Numerical results were in close agreement with experimental results.