Abstract

The use of fiber-reinforced polymer (FRP) composites in structural applications is increasingly widespread due to their light weight and load-bearing capacity. However, their behavior under fire exposure presents unique challenges—such as thermal buckling and post-buckling response—that current regulations, including Eurocode and SOLAS, do not specifically address. This work investigates the phenomenon of thermo-inelastic buckling in composites, taking into account their flexibility, thermal degradation, and natural imperfections. A modeling approach is proposed that integrates Felippa’s corotational theory, isotropic damage models with SPROM, and thermo-mechanical coupling. These methodologies are validated across scenarios ranging from one-dimensional to three-dimensional thermal buckling, including experimental validation. The results highlight the limitations of traditional approaches based on slenderness and inelasticity, such as the Tsai-Wu method, and emphasize the need for design frameworks that incorporate structural fire response in composite materials. This work aims to bridge the gap between the growing use of these materials and the design methodologies required for fire-resistant applications.