Pomelo-inspired sandwich composites: manufacturing and cushioning property

Abstract

Inspired by pomelo peel, this study designs an effective cushioning composite with a novel sandwich structure using a columnar lattice mold and two-step foaming technique. This sandwich composite consists of a polyamide nonwoven fabric (i.e. nonwoven surface) as the surface reinforcement layer and a double-layered spacer fabric as the bottom layer for energy absorbing. The static-compression resistance and dynamic cushioning efficacy of composites are investigated, examining the influences of three parameters (i.e. the areal density of the nonwoven surface and laminating angle and the mesh size of the double-layered spacer fabric). The experimental results show that the static-compression resistance and dynamic cushioning efficacy of the composites decrease when increasing the laminating angle of the spacer fabric and the areal density of the polyamide nonwoven fabric. By contrast, with an increment in mesh size, the compression resistance and cushioning efficacy of the composites first decrease and then increase. N200PUH/L(S5) consists of a 200 g/m2 nonwoven surface and a 0° laminated angle, 5 mm mesh size double-layered spacer fabric, which exhibits a higher cushioning efficacy than the pomelo peel. The acceleration of N200PUH/L (S5) was 39 g at 15 ms, and the acceleration of pomelo peel was 72 g at 7 ms, which were 60.7% and 28.5% lower than that of the blank group, respectively. The sandwich-structured composites are proven to have promising applications for low-velocity cushioning behavior, and this study combines the textile structure and foam technique, offering a perspective of designing cushioning composite sandwiches for future studies.