The influence of preparing method on novel x-truss/foam sandwich structure

Novel X-truss/foam sandwich structures were prepared by Z-pin inserted and bias stitching method, respectively, in order to improve the transverse mechanical behavior. With such reinforcements, the collapse resistance capability of the core and the bonding strength between the core and the skins are obviously increased. Thus the principal disadvantages of conventional sandwich structures are solved. The Z-pins and stitches embedding in rigid polyurethane foam configured a truss, which was made of carbon fiber/epoxy resin. The architectures of specimens made from Z-pin inserted and bias stitching methods are very similar but not identical, which make their mechanical performances different from each other. In order to evaluate these two methods, out-of-plane mechanical tests, such as compression, shear, and tension were practiced and failure modes were compared. In some conditions, the specimens made from the Z-pin inserted process have a higher compression modulus, but a lower tension and shear strength compared to that made from the bias stitching process. Moreover, there are big differences in their failure modes.