Development and validation of finite element models for buckling of open-hole fiber-reinforced composites at ambient and cryogenic temperatures

Understanding the buckling behavior of fiber-reinforced composites (FRCs) is critical for the design of composite structures. In this study, finite element (FE) models of FRC buckling behaviors were developed and validated. The validated FE models could accurately predict the numerical and experimental observations in the literature. The effect of the specimen geometric imperfections was included in the model to secure a realistic FE model; to this end, linear buckling analyses were employed before beginning the nonlinear buckling analyses. The FRCs' mechanical properties and buckling behavior of FRCs can be temperature-dependent. Because the presence of a hole in the design of composite structures may be inevitable in a few applications, the temperature-dependent buckling responses of open-hole glass/epoxy, glass/polyester, carbon/epoxy, and carbon/polyester composites were compared with those of the plain specimens. The effects of the fiber and resin types, temperature, and the presence of holes on buckling behavior were investigated and discussed in detail. Five different temperatures, 25, 0, -50, -100, and -180 degrees C were considered. The cryogenic temperatures raised Young's moduli and consequently raised the critical buckling loads. The validated models and results on the open-hole composites can be used as benchmarks in composite structure designs involving buckling behavior.