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针对准脆性材料的非线性特征,在热动力学框架内,建立了准脆性材料的弹塑性与各向异性损伤耦合的本构关系.对准脆性材料的变形机理和损伤诱发的各向异性进行了诠释,并给出了损伤构形和有效构形中各物理量之间的关系.在有效应力空间内,建立了塑性屈服准则、拉压不同的塑性随动强化法则和各向同性强化法则.在损伤构形中,采用应变能释放率,建立了拉压损伤准则、拉压不同的损伤随动强化法则和各向同性强化法则.基于塑性屈服准则和损伤准则,构建了塑性势泛函和损伤势泛函,并由正交性法则,给出了塑性和损伤强化效应内变量的演化规律,同时,联立塑性屈服面和损伤加载面,给出了塑性流动和损伤演化内变量的演化法则.将损伤力学和塑性力学结合起来,建立了应变驱动的应力-应变增量本构关系,给出了本构数值积分的要点.以单轴加载-卸载往复试验识别和校准了材料常数,并对简单试验进行了预测,结果表明,所建本构模型对准脆性材料的非线性材料性能有良好的预测能力.
Aiming at the nonlinear characteristics of quasi-brittle materials, the constitutive relation between elasto-plasticity and anisotropic damage coupling of quasi-brittle materials is established in the framework of thermodynamics.The mechanism of deformation and the anisotropy induced by damage The relationship between the damage configuration and the physical quantities in the effective configuration is given.In the effective stress space, the plastic yield criterion and the plastic following dynamic strengthening law and the isotropic strengthening law are established. Based on the plastic yield criterion and the damage criterion, the plastic potential functional and the damage criterion are established based on the plastic strain criterion and the damage criterion Damage potential function, and by the law of orthogonality, the evolution law of the variables within the plasticity and damage strengthening effect is given. Simultaneously, the plastic yield surface and the damage loading surface are combined to give the evolution of the variables in plastic flow and damage evolution Law is combined with damage mechanics and plasticity mechanics to establish strain-driven constitutive relation of stress-strain increment, and the key points of constitutive numerical integration are given.A single-axis loading-unloading reciprocating test The material constants were identified and calibrated, and the simple tests were predicted. The results show that the proposed constitutive model has a good ability to predict the nonlinear material properties of brittle materials.