Low-velocity impact response of aluminum alloy corrugated sandwich beams used for high-speed trains

The low-velocity impact response of A6N01S-T5 hollow extruded aluminum alloy corrugated sandwich beams used for the carbody of high-speed trains, under drop-weight impact was investigated in this study. A failure mechanism map of the corrugated sandwich beam under low-velocity impact was obtained by theoretical analysis, which was verified by experimental and finite element simulation results. Typical deformation mode, load-displacement response, and energy absorption of dynamically-loaded corrugated sandwich beams were discussed, and the effects of initial impact energy and impact angle on the impact response of specimens were also explored. The results indicate that there are three initial failure modes of corrugated sandwich beams under the drop-weight impact, namely face-sheet yield, face-sheet buckling, and core buckling, and both initial failure mode and critical load of sandwich specimens are sensitive to the face-sheet thickness and core thickness. The shear deformation of the corrugated core and gradually loading load-displacement response were observed for the case of forward impact, while the compression deformation of the corrugated core and load-displacement response with a larger initial peak were found for the case of reverse impact. Regardless of forward impact or reverse impact, the increase of initial impact energy will lead to the increase of maximum displacement response and structural resistance of sandwich beams. The increase in impact angle leads to the larger values of peak load, deformation resistance, and energy absorption efficiency of specimens for an impact angle less than 60 degrees, while the dynamic response of specimens is not sensitive to the increased impact angle within 75 to 90 degrees.