Abstract：Strength softening and stiffness degradation, unilateral effects, strength enhanced under confine and soften upon tension and compression, irreversible deformation, dilation and non-elastic expansion, all of above non-linear properties were considered, and within the framework of the thermal-dynamics, the coupling of anisotropic damage and plasticity constitutive model for the quasi-brittle materials has been established in this paper. The deformation mechanisms of brittle materials and damage-induced anisotropy have been interpreted; meanwhile the relations among various physical quantities between the damage configuration and effective configuration have been developed. The plastic yield criterion and the different plastic kinematic hardening rule and isotropic hardening law for the tension and compression have been studied in effective stress space. Within the damage configuration, adopted strain energy release rate, the tension and compression damage criteria have been established, and the different kinematic hardening rule and the isotropic hardening law for the tension and compression damage have been studied simultaneously. Based on the plastic yield criterion and damage criterion, the plastic potential functions and the damage potential function were constructed. The evolution of strengthening effect plastic and damage internal state variables have been derived through the orthogonal principle, at the same time, the evolution of the internal state variables, which described the plastic flow and damage evolution, have been developed through combination of plastic yield surface and damage loading surface. Integrated the damage mechanics and plasticity, the strain-driven stress-strain incremental constitutive relation has been established, and the key points of the numerical integration about the constitutive equations were given. The identification and calibration of constitutive material constants have been accomplished through uniaxial loading - unloading cyclic loading test, and the uniaxial monotonic test, uniaxial loading - unloading cyclic loading, two-axis pressure, two-axis tension and compression tests and triaxial compression tests Were predicted and compared with experimental results. The results show that the constitutive model has good predictive ability for nonlinear material properties of quasi-brittle materials.
2012, Vol. 33 
