Session: 02-10-02 Fatigue and Fracture Reliability 2

Submission Number: 182393

Numerical Study on Residual Stress Relaxation of Gusset Joint Improved by Portable Pneumatic Needle-Peening Treatment Under Overload 

Welding techniques are widely used in the construction of engineering structures. Due to the vulnerability of welded details to crack initiation, most service failures of welded structures are attributable to fatigue. Thus, various post weld improvement techniques are proposed to increase the fatigue strength of welded joints, especially for the lightweight design requirement of using high strength steels. International Institute of Welding (IIW) introduces the term “High Frequency Mechanical Impact” (HFMI) to describe one group of weld treatment techniques newly developed in the last two decades. HFMI treatment introduces both geometrical and RS beneficial effects by the impacted energy of cylindrical indenters with high frequency (about 90Hz). Compared to other methods, HFMI treatment is more user-friendly, safer, relatively lower-cost and produces finer surface finish. However, experimental and numerical studies for the crack propagation of HFMI-treated welded joints are limited in the literature. There are very few applications on the modeling of sequential simulations of welding, peening and crack propagation of welded joints.

    Portable pneumatic needle-peening treatment (PPP) used in this study was proved to be qualified as HFMI treatment (At least 3 fatigue class enhancement). The welding process, peening treatment and crack propagation of welded joints is simulated by a proposed numerical system. The crack propagation lives are compared to the experimental data to verify the numerical results. Based on the numerical system, the history of stress intensity factor ranges and the crack propagation lives under as-welded and as-peened states are analyzed. The results show that PPP reduces the effective SIF ranges during the crack propagation of the welded joint, increasing the crack growth resistance and fatigue life.

Presenting Author: Xipeng Chen The University of Osaka

Presenting Author Biography: Sep. 2016 ~ Jun. 2020, B.Eng,
Naval Architecture and Ocean Engineering, Wuhan University of Technology, China
Sep. 2020 ~ Jun. 2023, M.Eng,
Naval Architecture and Ocean Engineering, Wuhan University of Technology, China
Oct. 2023 ~ Up to now, Ph. D. candidate
Naval Architecture and Ocean Engineering, The University of Osaka, Japan

Authors:

Xipeng Chen The University of Osaka
Naoki Osawa The University of Osaka
Sherif Rashed CAE Lab
Takaaki Takeuchi The University of Osaka