Energy Absorption Characteristics of Stitched Composite Sandwich Panels

Abstract

The energy absorption characteristics of sandwich panels with through-the-thickness stitches, under edgewise compression, was investigated by conducting static crush tests. The effects of stitch row spacing on the sustained crush load were of particular interest. Also, the effects of the stitch spacing on the instability preceding the crush failure mode was investigated using finite element analysis. The analysis indicated that the local instability mode was influenced by the stitch row spacing only when the spacing was less than the semi-wavelength of wrinkles that would develop in the absence of stitches. The static crush tests showed that the average sustained crush load increases with reduced stitch row spacing and thereby increasing the total energy absorbed. The other parameters of interest that were investigated were the load ratio and the load uniformity index.