Evaluation of fatigue life of polycrystalline structural alloys

Research Institute for Mechanics, National Research Lobachevsky State University of Niznhy Novgorod, Nizhny Novgorod, Russian Federation

^* Corresponding author: pmptmvgavt@yandex.ru

Abstract

A mathematical model describing the processes of elastoplastic deformation and damage accumulation under low-cycle loading has been developed, based on the viewpoint of mechanics of damaged media (MDM). The MDM model consists of three interrelated parts: defining relations describing elastoplastic behavior of the materials, taking into account its dependence on the failure process; evolutionary equations describing the kinetics of damage accumulation; strength criteria of the damaged material. In order to assess the reliability and scope of applicability of the defining relations of mechanics of damaged media, the processes of plastic deformation and damage accumulation in variety of structural steels in low-cycle tests have been numerically analyzed, and numerical results obtained have been compared with the data of full-scale experiments. It is shown that the presented model of mechanics of damaged media adequately describes, both qualitatively and quantitatively, with accuracy, necessary for practical calculations, the main effects of the processes of plastic deformation and damage accumulation in structural alloys under block-type non-stationary non-symmetrical low-cycle loading.