Scaling effects in the mechanical response of sandwich structures based on corrugated composite cores

This paper investigates the compression response of all-composite sandwich structures based on glass fibre/epoxy and carbon fibre/epoxy cores. The structures were manufactured by wrapping layers of composite prepreg around a series of adjacent steel cylinders. Prepreg surface layers were then attached to the upper and lower surfaces of these wrapped cylinders and the entire structure cured in a hot press. Co-curing the skins and the corrugated core in this fashion ensured a strong bond in the critical skin-core interfacial region. The mechanical response of the sandwich structures was modelled using the finite element method. Initial attention focuses on investigating the effect of varying key geometrical parameters, such as the corrugation thickness and the number of unit cells, on the mechanical properties of the sandwich structures. The failure mechanisms during compression loading are discussed and compared with the numerical predictions from the finite element models. The second part of this study investigates scaling effects in the compression response of both the carbon and glass fibre-based sandwich structures. In this part of the study, the geometry of the sandwich structures, as well as the relevant testing conditions, were varied in order to ensure a consistent scaling approach. Here, variations in compression strength as well as changes in failure mode were investigated with increasing scale size.