An experimental study of low-velocity impact responses of sandwich panels for Korean low floor bus

This paper describes the results of an experimental investigation on the low-velocity impact response of four different types of sandwich structures considered as the structural materials of the Korean low floor bus. The test panels were subjected to low-velocity impact loading using an instrumented testing machine at six energy levels. Impact parameters like maximum contact force, contact time, deflection at peak load and absorbed energy were evaluated and compared for different types of sandwich panels. The extent of the damage and depth of the permanent indentation was measured quantitatively using 3-dimensional scanner. Failure modes were studied by sectioning the specimens and observed under optical microscope. The impact test results show that sandwich panels with woven glass fabric/epoxy facesheet could not observe permanent visible impact damage and has a good impact damage resistance in comparison with sandwich panel with metal aluminum facesheet.