Fatigue strength assessment of load-carrying cruciform joints in low- and high-cycle fatigue region based on effective notch strain concept

Abstract

This study newly defines the concept of effective notch strain and examines its applicability in elastic and elasto-plastic condition for load-carrying cruciform welded joints. Low- and high-cycle fatigue tests were performed on specimens. To calculate the effective notch strain, the reference radii of 0.3, 0.5, and 1.00 mm are assigned to the analysis model, elastic, and elasto-plastic analyses that were performed under the same condition as the experiments. By arranging the fatigue strength using the effective notch strain concept, it is possible to assess fatigue strength using FAT value of 200 from low- to high-cycle fatigue region. Furthermore, the simple method for estimating effective notch strain was proposed and verified by the experiments.