Coupled thermal–mechanical modeling of carbon fibers reinforced polymer composites for damage detection

Abstract

An analytical solution is derived to describe the correlation between the thermal resistance change and fiber damage evolution in unidirectional composites under loading conditions. A key parameter, thermal characteristic length, is obtained, which represents the sensitivity of the thermal property change to mechanical damage. A coupled thermal–mechanical model is also developed to predict the failure stress, internal fiber breakage and thermal resistance change as a function of applied strain. The results show that the number of fiber breaks is proportional to thermal resistance change during loading while the thermal resistance change increases exponentially with increasing the applied strain. The analytical solution is in good agreement with the numerical results. Finite element models are developed to verify the coupled thermal–mechanical models. The present study shows that longitudinal thermal resistance change is sensitive to damage in a predictable manner and can be used together to improve the reliability of damage assessment during loading of carbon fiber reinforced polymer.