The main laws of the processes of creep and long-term strength of polycrystalline structural alloys are considered. From the viewpoint of continuum damaged media (CDM), a mathematical model is developed that describes the processes of viscoplastic deformation and damage accumulation under creep. The problem of determining material parameters and scalar functions of the developed constitutive relations based on the results of specially set basic experiments is discussed. An experimental–theoretical methodology for determining material parameters of the derived constitutive relations of CDM is developed based on analyzing the viscoplastic deformation and failure processes of laboratory specimens in the conditions of soft loading (stress controlled). Experimental results of short-term creep of the VZh-159 heat-resistant alloy are presented. The obtained numerical results are compared with the test data using the numerical modeling method of experimental processes. Qualitative and quantitative agreement between numerical results and experimental data is shown. It is concluded that the developed constitutive relations are reliable, and that the proposed methodology accurately determines the material parameters of the model under degradation of initial strength properties of structural materials according to the long-term strength mechanism.

考虑了多晶结构合金的蠕变过程和长期强度的主要规律。从连续介质损伤介质（CDM）的角度，建立了描述蠕变下粘塑性变形和损伤累积过程的数学模型。讨论了根据专门设置的基础实验的结果确定已发展本构关系的材料参数和标量函数的问题。在分析软载荷（应力控制）条件下实验室试样的粘塑性变形和破坏过程的基础上，开发了一种确定 CDM 本构关系材料参数的实验-理论方法。介绍了 VZh-159 耐热合金的短期蠕变实验结果。使用实验过程的数值模拟方法将获得的数值结果与测试数据进行比较。显示了数值结果和实验数据之间的定性和定量一致性。得出的结论是，所建立的本构关系是可靠的，并且所提出的方法根据长期强度机制准确确定了结构材料初始强度特性退化下模型的材料参数。