Unlocking the Hidden Failure Behavior and Mechanisms: High‐Temperature Thermo‐Mechanical Coupling in Glass Fiber Reinforced Epoxy Composites

ABSTRACT Glass fiber reinforced epoxy composites are widely used as structural parts and carry tensile mechanical loads in industry. However, once the material is heated, it is very easy to fail and cause damage to the entire structural system. In this article, a thermo‐mechanical coupling experimental platform was independently constructed, and the failure behavior and mechanism of glass fiber reinforced epoxy composites were systematically studied. It was found that the composite samples exhibit softening failure and fracture failure under different working conditions, and the failure form was related to its ambient temperature and stress level. On this basis, the critical conditions of different failure forms of composites were given. Further research on glass transition and pyrolysis indicated that they were related to the decrease in the bonding ability of the matrix and fiber, as well as stress concentration on the surface of the glass fibers. A thermo‐mechanical coupling failure model for the composite materials was also established based on kinetic parameters. It accurately predicted the surface temperature and failure time of the samples. This work will provide a reference for the application of composite materials in practical engineering and provide new ideas for related research on improving the safety of composite materials.