Damage accumulation in cyclically stable steel under low-cycle loading

Abstract

Abstract Abstarct. The contribution of variable plastic strains (hysteresis loop), unilaterally accumulated plastic and elastic strains in the total accumulated damage in the limiting case (macro-crack formation) under quasi-static fracture is shown on the basis of the deformation-kinetic criterion of fatigue failure of cyclically stable steel, when the accumulated plastic strain is equal to or commensurable with the strain of a single (static) fracture. It is shown that in the case of low-cycle failure, the main damaging fraction is introduced by the static component (unilaterally accumulated strain), the value of which decreases with the increase of the number of cycles to failure (reduced load amplitude). This increases the contribution of variable cyclic strain. The influence of elastic strain in the area of quasi-static fracture is negligible, and the calculation of durability in practical applications can be carried out without taking into account the damaging role of elastic strains.