High-temperature effect on continuous glass fiber reinforced polypropylene multilayer composite and corrugated sandwich panels

The high-temperature mechanical behaviors of Multi-Layer Composite Panels (MCP) and Corrugated Sandwich Panels (CSP) of Continuous Glass Fiber-Reinforced Polypropylene (CGFRPP) are critical for their application in aerospace fields, which have been rarely mentioned in previous studies. High-temperature quasi-static tensile and compression tests on CGFRPP MCP are conducted first. The results showed that the tensile and compression strength, stiffness, and tensile modulus of MCP decreased with increasing temperature. The Gibson model was found to be more suitable for predicting the high-temperature mechanical performance of MCP after comparing the calculated results of different theoretical models with experimental data. Secondly, high-temperature planar compression tests were conducted on the CGFRPP CSP, revealing that the main failure modes were corrugated core buckling and delamination between the face panel and core material, with delamination being intensified at higher temperatures. Therefore, we proposed a strength theoretical model that considers structural buckling failure and interface delamination failure, and introduced the influence factor to evaluate the effect of interface delamination on structural strength.