Investigation on manufacturing and mechanical behavior of all-composite sandwich structure with Y-shaped cores

A novel all-composite sandwich structure with Y-shaped cores was designed and fabricated by hot-press molding method in this paper. In order to reveal effects of relative density on mechanical behavior, the out-of-plane compressive tests were carried out on composite sandwich structures with different relative densities, varying from 5.34% to 10.53%. Then the effects of relative density on failure modes, mechanical properties, stress-strain curves and energy absorption capacity were studied and analyzed. The results showed that the relative density had visible impact on mechanical behavior of sandwich structure. The stress-strain curves possessed the characteristic of two peaks, and the peak stresses increased as the relative density increased. The numerical simulation based on progressive damage model was developed to reveal the damage evolution process and predict the mechanical properties. Analytical predictions were also presented to predict the compressive strength and stiffness of Y-shaped core, which were compared with numerical results and experimental results. It was observed that the analytical predictions and numerical results were in good agreement with the experimental results.