Thermal Expansion Process for Manufacturing of Stitched Sandwich Structures

A thermal expansion process was applied to prepare stitched sandwich structures using the pressure generated by the foam core inside a closed mold. In this way, buckling of stitches was avoided. The mechanical properties of the specimens prepared by thermal expansion process were significantly improved when compared to that of specimens prepared using the hot press. In order to increase the thermal expansion pressure, the foam cores were pre-compressed, and then stitched with the face sheets. The pre-compressed foam cores underwent thermal expansion easily and their thermal expansion pressure increased with increase in pre-compressive ratio.