Local MIL-HDBK-5D equivalent stress based fatigue assessment of the gusset welded joint improved by Portable Pneumatic Needle-Peening treatment

Abstract

This study proposes a local MIL-HDBK-5D equivalent stress (LMES) based approach to investigate the fatigue lives of Portable Pneumatic Needle-Peening (PPP) treated gusset welded joints made of SM490. The LMES range is identified by the elastic–plastic local stress cycle simulated by the muti-process finite element analysis, including welding, PPP, and fatigue loading processes. Using the LMES, Fatigue test results of as-welded (AW) and PPP treated joints are consolidated into a single S-N curve. This LMES based S-N curve can be used for evaluating fatigue life comprising the influence of residual stress, cyclic stress relaxation, and local weld toe geometry for welded joints studied in this work.