MULTIAXIAL FATIGUE CRITERIONS APPLIED TO MECHANICAL COMPONENTS

FEDERICO CAVALIERI; ALBERTO CARDONA; JOSÉ RISSO

San Nicolás

Congreso; Congreso SAM/CONAMET 2007; 2007

In many practical situations, mechanical components are subjected to multiaxial loading and the required design lifetime often exceeds 108 cycles. For example, the expected lifetime of engine components, railroad wheels, crankshafts, turbine blades, etc. is more than 109 cycles. The traditional fatigue criterions assumed a hyperbolic relationship between stress and fatigue life, but experimental results in steels show that the fatigue fracture can occur beyond 10^7 cycles. This means that for very high number of cycles the fatigue limit does not an asymptotic behaviour and the concept of infinite fatigue life is not correct. So, the fatigue in metal components with design lifetimes greater than 10^7 cycles is an interesting topic for the development of advanced technologies. Taking into account that experimental fatigue tests are very expensive and time-consuming, the development of numerical fatigue models capable of predicting the durability of components, is a key task to carry out mechanical components design in shorter times. Multiaxial fatigue criterions can be classified in the following way: 1) Empirical, 2) Stress Invariants, 3) Critical Plane, 4) Strain Energy, 5) Combined Energy/Critical Plane and 6) Mesoscopic. In this paper, we present results from numerical models using the finite element method (FEM) analyzing mechanical components subjected to high number of impact cycles with an invariant criterion.