TY - JOUR
TI - Evaluating long-term strength of structures
AU - Volkov Ivan A
AU - Igumnov Leonid A
AU - Shishulin Denis N
JN - Thermal Science
PY - 2019
VL - 23
IS - 12
SP - 477
EP - 488
PT - Article
AB - The issue of evaluating strength and service life is discussed as applied to  structures, the exploitation properties of which are characterized by  multi-parametric nonstationary thermal mechanical effects. The main  requirements to mathematical models of the related processes are formulated.  In the framework of mechanics of damaged media, a mathematical model  describing processes of inelastic deformation and damage accumulation due to  creep is developed. The mechanics of damaged media model consists of three  interconnected parts: relations defining inelastic behavior of the material  accounting for its dependence on the failure process, equations describing  kinetics of damage accumulation, and a strength criterion of the damaged  material. The results of numerically simulating the carrying capacity of a  nuclear power plant reactor vessel in the event of a hypothetical emergency  are presented. Emergency conditions were modeled by applying pressure  modeling the effect of melt-down, the constant internal pressure and  temperature varying within the part of the vessel in question. The analysis  of the obtained numerical results made it possible to note a number of  characteristic features accompanying the process of deformation and failure  of such facilities, connected with the time and place of the forming  macrocracks, the stressed-strained state history and the damage degree in the  failure zone, etc. The results of comparing the numerical and experimental  data make it possible to conclude that the proposed defining relations of  mechanics of damaged media adequately describe degradation of the initial  strength properties of the material for the long-term strength mechanism and  can be effectively used in evaluating strength and service life of structures  under thermal mechanical loading.