Thermo-mechanical Coupling Constitutive Model of Concrete Based on Thermodynamics

In order to describe the mechanical properties of concrete under high temperature,a thermomechanical model for concrete with the influence of temperature was presented in this paper. It based on thermodynamic theory and combined the damage theory with the classic elasto-plastic theory,which was used to describe the mechanical properties of concrete under high temperature. Firstly,the elastic strain increment under elevated temperature was derived on the basis of the rmodynamic principle. Then,a hardening parameter based on the classical plastic theory was constructed,with consideration of the influence of temperature. A plastic strain increment expression was obtained. With superposition of the two part strain increment, the expression of thermal-mechanical coupling constitutive model was established. The model was calibrated with the experimental results. It proves that the thermalmechanical coupling constitutive model can more accurately describe the mechanical properties of concrete under high temperature.