Impact response of three-dimensional stitched sandwich composite

The paper aims at evaluating the damage resistance of sandwich structures composed of stitched foam core and glass facesheets subjected to low-velocity impact. To obtain a suitable baseline comparison, the equivalent set of properties was measured for an equivalent unstitched sandwich. Based on the force and energy histories, parameters have been introduced as following: load at incipient damage, maximum load, penetration depth at maximum load, total energy absorbed during impact and impact damage area. The impact resistance of the sandwich structure is greatly improved by the presence of the stitches. Skin/core delamination is limited and initial energy is used to degrade core’s stitches. Moreover the global behavior under impact is influenced by the stitching geometrical parameters.