Experimental and numerical investigation of effects of residual stress and its release on fatigue strength of typical FPSO-unit welded joint. (15th January 2020)

• Record Type: Journal Article
• Authors: Li, Liangbi; Jia, Qianqian; Wan, Zhengquan; Zhang, Yiwen; Qian, Peng; Li, Jichun
• Is Part Of: Ocean engineering. Volume 196(2020)
• Publication Date: 2020-01-15
• Subjects: Welded joint -- Residual stress release -- Fatigue -- Experiment -- Numerical simulation; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2019.106858
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: Floating production storage and offloading (FPSO) units are important to deep-water engineering. However, the welding of some important joints of the units induces significant residual stresses, which could be released under external loading, with significant safety implications. Firstly, the residual stress and its release under loading were measured by a non-destructive X-ray method, and also simulated with the thermal elastic-plastic theory. Then, the effect of residual stress and its release on fatigue life of the welded joint was tested with a designed experimental setup and simulated with S – N curve method. The experimental and simulation results were found to be essentially consistent. The consideration of the residual stresses in a typical welded joint significantly decreased the fatigue life. Hence, for service safety, the residual stresses should always be considered in the analysis of the fatigue life of a welded FPSO structure. Highlights: Investigate the effects of residual stress and its evolution on the fatigue life of a welded joint in an FPSO unit. The relationships among the residual stress, external load, and fatigue life of the joint were established. The fatigue life was tested by the designed experimental setup.