Щодо моделювання розповсюдження тріщин втоми в тонких ізотропнх пластинах в умовах двовісного асиметричного розтягу-стиску

Abstract

The modelling of the fatigue fracture process of the thin isotropic infinite plates with cracks under external biaxial asymmetric cyclic loading is considered. The solution of the problem is based on the joint consideration of the fracture mechanics and continuous damage mechanics concepts and using two types of equivalent stress criteria’s. The first one reduces an asymmetrical cyclic load to the equivalent symmetric cyclic load in time of the rupture. The second one reduces a plane stress state in the vicinity of the top crack to a single-axial one. The obtained system of equations of the model a relatively equivalent stress intensity factor allows us to determine the duration of the incubation stage and the rate of fatigue crack propagation in plates with different stress concentrators. The calculated dependences of the crack length, which extends from the circular hole, from the number of load cycles in the infinite aluminum plate with a circular hole at the variation of the parameters of the asymmetrical cycle and the coefficient of the biaxiality loading are constructed.