МОДЕЛЬ ПОВРЕЖДЕННОЙ СРЕДЫ ДЛЯ ОПИСАНИЯ ДЛИТЕЛЬНОЙ ПРОЧНОСТИ КОНСТРУКЦИОННЫХ МАТЕРИАЛОВ (МЕТАЛЛОВ И ИХ СПЛАВОВ)

Abstract

The main laws of processes of deformation and degradation of the initial strength properties of structural materials (metals and their alloys) according to the long-term strength mechanism are considered. In the framework of damaged medium mechanics, a mathematical model describing processes of inelastic deformation and damage accumulation in the presence of creep is developed. The model consists of three interconnected parts: relations defining inelastic behavior of the material, accounting for the effect of the failure process; equations describing kinetics of damage accumulation; a strength criterion of the damaged material. Results of experimentally studying short-term creep of VZh-159 heat-resistant alloy under constant temperatures and different values of stress applied to the specimens are given. The deformation and damage accumulation process is numerically analyzed; the obtained numerical results are compared with the data of full-scale experiments. The comparison of the numerical and experimental data makes it possible to conclude that the present defining relations of damaged medium mechanics in the presence of degradation of the initial strength properties of structural materials according to the long-term strength mechanism are adequate. Keywords: transient creep, long-term strength, modeling, defining relations, damaged medium mechanics, temperature, damage degree, material parameters, numerical and full-scale experiments.