Study on Molding Pressure of X-truss/Foam Sandwich Structures

Abstract

X-truss/foam sandwich structure with prominent compression and shear strength has broad application prospects as primary structure in aircraft, truck, and other fields. But unsuitable molding pressure usually causes quality defects such as poor skin—core adhesion or broken Z-pins, which seriously decreases the structure’s mechanical property and induces too much thickness error. In order to obtain a suitable molding pressure, the hot pressing process was analyzed. It was found that the suitable molding pressure is mainly determined by the property of the foam core, the resisting force of Z-pin inserting into the face sheets, as well as Z-pin inserting angle and density. In the calculated suitable molding pressure, X-truss/ foam sandwich structures were successfully fabricated using carbon fiber Z-pins and face sheets together with polymethacrylimide foam core. The thickness of sandwich structures and final inserting angle of Z-pins were basically consistent with the calculations.