FCP Report No. 1

Fatigue Damage Analysis for Irregular Shaped Structures Subjected to Representative Loads


J. F. Martin
Department of Theoretical and Applied Mechanics


A fatigue damage analysis is presented that is capable of analyzing structures subjected to representative service load histories. After theoretically or experimentally determining the nominal stresses or strains, a mechanics analysis combined with a model of uniaxial stress-strain behavior calculates the stress-strain response at the critical location. Based on the stress-strain response at the highly strained region, a cumulative damage procedure that sums damage over small increments of the local stress-strain curve and corrects for the effect of mean stress estimates the total number of reversals to crack initiation.

This procedure is applied to a box-beam structure and an automotive fan blade. Analyses were made for both constant and variable types of loading patterns..

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