Wrinkling and Compression Failure Transition in Sandwich Panels

This paper investigates the transition from face wrinkling failure to face sheet compression failure, the latter induced by local buckling at fibre level, so called face sheet microbuckling. An experimental series is performed on small sandwich panels subjected to uni-axial compression. Two different face sheet lay-ups are used in conjunction with a range of PVC core material densities. The results are compared to analytical wrinkling formulae and the correlation is found to be very good. The experimental results also clearly show the transition from wrinkling failure to face sheet microbuckling failure when the core modulus exceeds a certain value. The localised failure surfaces are inspected by microscope and some different characteristics of the failure modes are indicated.