Failure analysis of fiber-reinforced composites subjected to coupled thermo-mechanical loading

Structures made of fiber reinforced composites have captured extensive attentions in the scientific and engineering communities due to their excellent performance and applicability. When these structures are in service, they are likely exposed to variations of ambient temperature that may have an impact on their strength. To study this effect, a coupled thermo-mechanical model is required. This paper develops a microscopic mechanical model to investigate failure of composite structures subjected to a coupled thermo-mechanical condition. Stiffness degradations of composite laminates are first investigated. A comparison between experimental data and theoretical results under the quasi-static loadings are presented to validate the proposed method. The method provides detailed microscopic stress distribution of the composites under the coupled thermo-mechanical loading for failure analysis, which shows that a higher ambient temperature variation will generally cause stiffness degradation and failure strength for both uniaxially and biaxially loaded laminates.