Improvement of the mechanical properties of Kagome structures using PUR foam matrices

Abstract This study investigates the opportunities of improvement of the compressive stiffness, strength, and energy absorption capabilities of metamaterial structures based on Kagome cells using rigid polyurethane (PUR) foam matrices for embedding. Three densities were considered for the Kagome structures: 142.8 kg m −3 , 198.2 kg m −3 , and 257.7 kg m −3 , respectively (corresponding to a relative density of approximately 0.1, 0.15, and 0.2 respectively), while the density of the PUR foam was maintained constant at 90 kg m −3 . The structures were incorporated in sandwich panels using thermoplastic polymer-reinforced woven glass fiber faces and were subjected to static and dynamic tests using a drop tower. Considering the weight added by the PUR matrix, the performance of the investigated structures was evaluated with respect to their density, the results showing better stiffness- and strength-to-weight ratios for the bare structures but significantly higher energy absorption capabilities for the embedded structures.