Fatigue failure transition analysis of load carrying cruciform welded joints by extended local approach

Abstract

This study was mainly concerned with the fatigue crack initiation points transition relationship between the weld toe and weld root in Load-carrying Cruciform Weld Joint (LCWJ) considering the mismatched filler material yield strength and geometrical sizes under cyclic loading conditions. The critical failure locations were investigated by the experimental tests and numerical simulations. To analyze the fatigue characteristic indicators of the potential fatigue initiations, different configurations of mismatch ratios and local geometries (plate thickness, weld size and penetration ratio) were designed to conduct the fatigue tests and cyclic calculations of CLWJ. Subsequently, New uniform effective notch energy indicator was proposed to characterize the low and high cycle fatigue life by extending the SED method. The related analytical formulations for weld toe and weld root were established to predict the low and high cycle fatigue assessment indicator of LCWJ considering the effects of plasticity and yield strength mismatch and geometry configurations. The effective notch energy relationship between the weld toe and weld root in LCWJ was estimated by the established analytical solutions.