Experimental study on high cycle fatigue performance and damage mechanism of welded tubular structures with butt joints

Yanlin Guan, Yaqiang Yang, Wenping Du, Mohamed F.M. Fahmy, Haitao Wang and Jing Cui

Abstract

Based on high-cycle fatigue tests and microstructural analysis, the fatigue performance and fracture failure mechanisms of butt joints in welded tubular structures were investigated. According to static behavior of the butt joints, high cycle fatigue experiments were carried out at different stress levels. A life prediction model for butt joints of welded tubular structures under high-cycle fatigue load was proposed by introducing Morrow stress-life fatigue curve. With fracture micro morphology analysis, the fracture failure mechanism of butt joints in welded tubular structures was revealed. The experiment results indicate that the welded tubular structure exhibited brittle damage at the weld seam under fatigue loading. The test was cycled 2 million times under the stress ratio R = 0.1, and the fatigue strength was 156.29MPa. The resulting fatigue life prediction formula demonstrated good agreement with the experimental results. Based on the fatigue experimental results, the fatigue life prediction model applied to high-cycle fatigue was established. With a large number of fatigue striations in the crack propagation zone, the fatigue fracture was smooth and neat at the crack source, while the final fracture zone occupied a small proportion of the fracture plane.

Key Words

butt joints; fatigue life; high-cycle fatigue testing; partial strain fatigue analysis; welded tubular structures

Address

Yanlin Guan:Dept. of Civil Engineering, School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China Yaqiang Yang:Dept. of Civil Engineering, School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China Wenping Du:Dept. of Civil Engineering, School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China Mohamed F.M. Fahmy:Dept. of Civil Engineering, Faculty of Engineering, Assiut University, Assiut, 71516, Egypt Haitao Wang:Dept. of Civil Engineering, College of Civil and Transportation Engineering, Hohai University, Nanjing,210098, China Jing Cui:Dept. of Civil Engineering, College of Civil Engineering and Architecture, Henan University of Technology, Zhengzhou, 450001, China

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