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

Submission Number: 182411

Numerical Study on Mixed-Mode Fracture Mechanics Parameters of Surface Cracks in an HFMI-Treated Welded Joint 

To elucidate the mechanism of fatigue strength improvement by High-Frequency Mechanical Impact (HFMI), it is necessary to analyze fatigue crack propagation considering the change of the toe profile and compressive RS (RS) distribution caused by HFMI treatment. In previous studies (e.g., Letner, M. et al., Weld. World (2014) 58,1:29-39), the RS distribution in the HFMI groove was approximated by a simple uniaxial stress distribution, and only the Mode I stress intensity factor (SIF) was evaluated. In this study, the mixed-mode stress intensity factor (MM-SIF) of surface cracks HFMI-treated T-welded joints is calculated with high accuracy using an automatic mixed-mode influence factor (IC) database generation system for surface cracks in welded joints developed by Kyaw et al. (Theor. Appl. Fract. Mech. (2020) 106:102471). The RS distribution is calculated by welding thermal elasto-plastic FE analyses and peening dynamic explicit elasto-plastic FE analyses. It is found that the SIF becomes positive in the absence of RS, but becomes negative when HFMI’s RS is taken into account. Abrupt circumferential changes in mode II/III SIF for the crack in an HFMI joint. This change is considered to be caused by the disturbance of the surface profile and RS distribution at the beginning and end of the HFMI process.

Presenting Author: Taiki Omura The University of Osaka

Presenting Author Biography: Mr. Taiki Omura will be received the B.E degree in engineering from Osaka University in FY2025, and will be Master course student in FY2026.

Authors:

Taiki Omura The University of Osaka
Phyo Myat Kyaw Institute of Maritime Technologies and Propulsion Systems
Zwe Letyar Htut The University of Osaka
Takaaki Takeuchi The University of Osaka
Naoki Osawa The University of Osaka