Influence of Process Pressure on Local Facesheet Instability for Ultra-light Sandwich Structures

Skin wrinkling phenomenon is 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 is established. It is observed that the size of the adhesive menisci between honeycomb cell walls and skin, and the waviness of the skin increases with process pressure. As these two effects exert opposing influences on the compressive strength of the skin, an optimal process pressure equal to 0.7 bar is identified experimentally and confirmed by an analytical model.