本文首先基于含裂纹材料的微观力学分析提出了一种损伤变量的选取方法。然后按照不可逆热力学的内变量理论导出了一种新的各向同性损伤本构模型。此模型抛弃了屈服面的概念,在算法上更加简明,并可退化为Lemaitfe损伤模型等多种已有的本构模型。最后,通过试验对模型进行了验证,并将其应用于多轴非比例加载变形特性描述、低周疲劳寿命预测以及结构变形与损伤分析。 This paper first proposes a method of selecting damage variables based on the micromechanical analysis of cracked materials. Then, according to the irreversible thermodynamic internal variable theory, a new isotropic damage constitutive model is derived. This model abandons the concept of yield surface, is more concise in the algorithm, and can be degenerated into many existing constitutive models such as the Lemaitfe damage model. Finally, the model was verified by experiments and applied to multiaxial non-proportionally loaded deformation characterization, low-cycle fatigue life prediction, and structural deformation and damage analysis.