Head, Fatigue-Fracture Group, Centre Technique des Industries Mécaniques (CETIM), Senlis,
Pages: 15 Published: Jan 1994
Methods for analyzing service time histories and simulating fatigue conditions are now well known and incorporated into application software. However, they carry a risk, if used routinely, that the effects of interaction of the material, the fatigue loading conditions, and the structural design are often too complex for correct evaluation using a single method of approach.
The first part of this paper presents the different phases that must be included in the methodology for predicting service fatigue life and recommends any steps in which the analysis parameters (significant amplitude level of maximum cycles or nondamaging cycles, choice of low- and high-truncation levels of the spectrum, choice of counting method, etc.) may be in contradiction with the real damage process of the material.
After determining the correct loading history, different ways of predicting fatigue life using two methods are presented, namely, 1. the use of damage laws for predicting the crack initiation life (or the damage tolerance approach with modeling of crack propagation), and 2. simulation of the loading history on a fatigue machine. The methodology used in this approach is presented together with precautions to be taken. These two methods are explained, along with the importance of the interaction of the material properties, the fatigue loading, and the design.
fatigue life prediction, mechanical structures, real service loading, simulations, loading spectrum, test automation, fracture (materials), fatigue (materials), testing methods, data analysis
Paper ID: STP13967S