Influence of process pressure on local facesheet instability for ultralight sandwich structures

The skin wrinkling phenomenon was investigated in the case of ultra-light sandwich structures with a honeycomb core manufactured by one-shot vacuum bag processing. The interplay between process pressure and compressive strength of the skin was established. It was observed that the size of the adhesive menisci between honeycomb cell walls and skin, and the waviness of the skin increased with process pressure. As these two effects exerted opposing influences on the compressive strength of the skin, an optimal process pressure equal to 0.7 bar was identified experimentally and confirmed by an analytical model.