Korytko Y. Development of the method for calculation of durability of structural members under periodically varying temperatures and loading

Object of investigation: durability and long-term structural strength under periodically varying temperature-stress fields. Purpose of investigation: development of the method for estimation of durability and long-term strength of structural elements, which are working under periodically heating and loading in conditions of irreversible creep deformation. Methods of investigation: the methods of creep theory and continuum damage mechanics, asymptotical methods, Finite Element Method with predictor-corrector multistep method of time integration, method of Cholessky. Theoretical and practical results: the method for durability analysis of structural elements under creep deformation and periodically varying temperatures and loading, and the software for the method implementation were developed. The numerical estimations of structural strength and durability of the nipples of the regenerator for catalytic cracking of petroleum, blades of gas-turbine engine, reflection shield of water-moderated water-cooled power reactor (WWPR-1000) were obtained. Science novelty: the new creep-damage constitutive equations for structural materials, subjected by periodically varying temperature, were developed. The laws of influence of periodically varying temperature field on the creep rate, damage accumulation, durability of structural members were established at first time. Degree of implementation: results of the dissertation were used for design of equipment in Company "LINIK" and for analysis of residual life of the reflection shield of nuclear reactor in National Science Center "KIPT". The branch of application: chemistry, power, atomic machine building.