Quasi-static and dynamic progressive crushing of CF/EP composite sandwich panels under in-plane localised compressive loads

This study investigates the in-plane localised crushing responses and progressive damage mechanisms of CF/EP composite sandwich panels under both quasi-static and dynamic loadings. The effect of the indenter shape on the damage mechanisms of the CF/EP composite sandwich panels under both quasi-static and dynamic in-plane localised crushing were investigated. It was found that the specimens were prone to lamina bending under quasistatic compression irrespective of indenter shapes, whilst the specimens failed mostly with fronds fracturing with different extents of transverse shearing under dynamic crushing. The specific energy absorptions of the CF/EP composite sandwich panels under dynamic impact are 20% lower than those under quasi-static compression. An energy balance model was adopted to analyse failure mechanisms and energy dissipation. To the model, the geometry of the debris wedge was predicted using an inverse calculation with experimental validation. The results show that the crush energy is mainly consumed by friction work and bending at about 55% and 35%, respectively.