Effect of core hybridization on the mechanical performance of sandwich composites

Sandwich structures have gained significant industry interest due to their excellent specific strength, stiffness, and energy absorption. Recent studies paid a lot of attention to sandwich composite structures and to how the addition of thermoplastic particles to cores of these sandwiches can enhance their performances. In this study, glass fabrics laminates manufactured via vacuum bagging process as skins for the sandwiches, while the cores made from epoxy without and with different concentrations of high density polyethylene. Flexural strength tests were conducted for all samples to investigate their capability for carrying-load and investigate their damage failures. Further, the finite element analysis (FEA) with commercial software, adopted to predict the damage failure modes for samples under flexural strength tests. Results illustrated that flexural strength decreased 11%, 12% and 13% after having 8%, 12%, and 16% HDPE in the cores of samples compare the sample without HDPE particles, meanwhile the flexural strain increased 80%, 87%, and 82% after adding 8%, 12%, and 16% HDPE in the cores of sandwich samples compare to the sample without HDPE particles. Results also reveal that the specific absorbed energy in the sandwich samples that have 8%, 12%, and 16% HDPE in their cores increased with 413%, 701%, and 363% in comparison with un-filled cores due to cores with thermoplastic particles have higher load-carrying and more plastic deformation with lower cracks propagation. Numerical simulation results for damage failure modes are in accordance with experimental results both qualitatively and quantitatively for all sandwich samples under flexural loading.