Static and low-velocity impact on mechanical behaviors of foam sandwiched composites with different ply angles face sheets

Abstract

The current studies give a brief account of analysis of static and low-velocity impact on foam sandwiched composites comprising composite faces from carbon/epoxy and cores from Rohacell (polymethacrylimide). The face sheets consist of four different stacking sequences as unidirectional, cross-ply, angle-ply and quasi-isotropic, which were fabricated by using hand lay-up process. Later, the composite panels were subjected to quasi-static and low-velocity impact loading using MTS and an instrumented Drop-Weight Machine (Instron 9250HV), respectively. The load-displacement curves have been obtained to characterize the failure mechanisms in the face sheets and the core. Impact parameters were evaluated and compared for different types of sandwich structures. Failure modes were studied by sectioning the samples at the impact location and observing under optical microscope. The results evaluated from static test have shown that the unidirectional have the highest peak load. However, the dynamic test data indicated that the foam sandwich with unidirectional face sheet have lowest peak load, lowest displacement at peak load and minimum energy absorption. It has also been observed that largest damage size, highest penetration depth and shear cracking have been experienced by unidirectional as compared to cross-ply, angle-ply and quasi-isotropic face sheets.