The prediction of dynamic fatigue life of multi-axial loaded system

Abstract

The purpose of this paper is to compare with estimation of equivalent fatigue load in time domain and frequency domain and estimatethe fatigue life of structure with multi-axial vibration loading. The fatigue analysis with two methods is implemented with various signalslike random, sinusoidal signals. Also, an equivalent fatigue life estimated by rainflow cycle counting in time domain is compared withresults estimated with probability density function of each signal in frequency domain. In case of frequency domain, equivalent fatiguelife can be estimated through Dirlik’s method with probability density function. The work proposed in this paper compared the fatiguedamage accumulated under uni-axial loading to that induced by multi-axial loading. The comparison was performed for a simple cantileverbeam exposed to vibrations of several directions. For verification of estimation performance of fatigue life, results are compared tothose of FEM analysis (ANSYS).