Effect of notch on fatigue performance of marine shaft made of 34CrNi3Mo alloy steel under torsional loading

• Published in: International journal of fatigue 2023-10, Vol.175, p.107790, Article 107790
• Main Authors: Hu, Yu, Zhang, Ding, Xu, Linzhi, Sun, Tianyang, Zhang, Peng, Lei, Jichao
• Format: Article
• Language: English
• Subjects: 34CrNi3Mo alloy steel; Fatigue life; Fracture micrograph; Notch; Stress concentration factor
• ISSN: 0142-1123; 1879-3452
• DOI: 10.1016/j.ijfatigue.2023.107790

•We performed a series of experiments to explore fatigue performance of smooth and notched specimens made of 34CrNi3Mo alloy steel under torsional loading.•Effect of notch on the fatigue performance of 34CrNi3Mo alloy steel under torsional loading is studied by comparing experimental results.•Micrograph and macrograph fractures of the 34CrNi3Mo specimens have studied to explore their failure mechanism and effect of notch on the fatigue performance.•Fatigue performance of 34CrNi3Mo specimens with v-notch at angles of angles of 45°, 90° and 135° was compared to exploit effect of notch by using validated numerical method. Joint of flange on a marine shaft subjected to torsional loading was more prone to occur fatigue fracture than the other section on the shaft due to stress concentration effect, so torsional fatigue performance in the vicinity of the joint should be payed more attention in terms of safe navigation of ships. The fatigue analysis of 34CrNi3Mo steel as a novel alloy material with a stress concentration factor of 1.45 under cyclic torsional loads was carried out based on the median S-N experimental method by simplifying the flange and shaft joint into 34CrNi3Mo specimens with u-notch subjected to torsional fatigue loading. The S-N curve and fatigue life of 34CrNi3Mo alloy steel were numerically calculated and compared with experimental fatigue life and the plotted S-N curve. It was found that fitting equation of the S-N curve was close to experimental results. Then, the fatigue performance of 34CrNi3Mo specimens with v-notch at angles of 45°, 90° and 135° was compared by means of the validated numerical method. The fracture macrographs and micrographs of the 14 specimens also were provided to explore the effect of notch on fatigue performance of the 34CrNi3Mo materials and to exploit the failure mechanism of fracture.