Micromechanics-based theoretical modeling and analysis of temperature and moisture-dependent tensile strength of fiber-reinforced polymer composites at hygrothermal conditions

This study examines the failure mechanisms of fiber-reinforced polymer (FRP) composites in hygrothermal conditions and develops a theoretical model for tensile strength prediction of FRP composites at various moisture and temperature levels. The model defines the function of water content in hygrothermal conditions and presents a physically-based framework for temperature and moisture-dependent tensile strength (TMDTS). It is based on the force-heat equivalence energy density (FHEED) concept. The model considers how the tensile strength is affected by temperature, Young's modulus, and particularly the hygrothermal conditions. It is confirmed by contrasting the proposed model's reasonableness with the available experimental data. Additionally, the work examined the factors affecting the FRP composites' tensile strength in a range of temperature and moisture conditions, and offering insightful knowledge about their properties. Ultimately, this study not only presents a reasonable theoretical approach for forecasting FRP composites' tensile strength under hygrothermal conditions but also offers suggestions for material evaluation and composites enhancement.Highlights A physics-based temperature and moisture-dependent strength model is proposed. The model considers the effect of hygrothermal condition on the tensile strength. The temperature and moisture-dependent tensile strength can be well predicted. This study deepens the understanding on the mechanical properties degradation.