Impact characterization of sandwich structures with an integrated orthogrid stiffened syntactic foam core

This paper presents the manufacturing, testing, and modeling of a new composite sandwich structure with a hybrid grid stiffened core. The hybrid core consists of a continuous fiber reinforced polymer orthogrid skeleton that is filled in with light weight syntactic foam in the bays or cells. The grid skeleton was manufactured by a dry weaving process per the pin-guided filament winding technology. Low velocity impact tests and compression after impact (CAI) tests were conducted to evaluate the impact response and residual strength of the sandwich structure. C-scan and SEM observation were implemented to investigate the impact damage. A finite element analysis using ANSYS was conducted to validate the compression test results. It is found that this integrated core enhances impact energy transfer, energy absorption, and positive composite action, insures quasi-static response to impact, and has higher CAI strength.