A predictive measure of thermomechanical coupling in elasto-viscoplastic composites

A set of thermo-elasto-viscoplastic analyses are performed to examine the effects of thermomechanical coupling in advanced composite materials. The constitutive equations for the orthotropic materials are formulated by adopting the unmixing-mixing scheme that is based on the micromechanics of composites. Then, considering restrictions from the second law of thermodynamics, the energy balance equation is derived for a class of orthotropic composites. As numerical examples, the temperature histories of off-axis specimens subjected to quasi-static cyclic loads are evaluated under adiabatic thermal conditions. In addition, as a measure of thermomechanical coupling effects, the irreversible viscoplastic energy developed in the specimens is carefully monitored. As a result, the numerical study shows that heating effects may be significant depending on the viscoplastic energy accumulated in a cycle.