Scholarlink

Abstract <p>The diameter increase and wall thickness thinning of coiled tubing (CT) are easily caused by plastic deformation, which seriously affects the service fatigue life of CT. Currently, the basic data of the CT fatigue life model are obtained from field operation and fatigue testing machines. Among them, the test procedure for the CT fatigue testing machine is complicated and wastes sample CT. As&#xa0;the research object CT-110, this work established a theoretical model of CT low-cycle fatigue life based on shaping strain. A numerical calculation model of the coupling relationship between CT fatigue life and cycle count is established based on the finite element method (FEM). Finally, experimental verification is carried out. The results show that the material on the compression and tension sides of the CT flows in the direction of the neutral axial, which leads to a significant thinning of the wall thickness of the CT under tension and compression. However, the material at the neutral axis is not subjected to plastic strain. Hence, the maximum plastic strain and fatigue-sensitive area of CT appear on the axial tensile plane and compression plane, which is consistent with the field failure of CT. The elastoplastic finite element (FE) results showed good agreement with experimental results. The numerical results make up for the inaccuracy of theoretical and experimental calculations in predicting the fatigue life of CT. The analysis results provide theoretical guidance for the prediction of CT fatigue life in actual operation, and it can provide a reference for field operators to effectively avoid economic losses caused by misoperation.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Low Cycle Fatigue Failure Analysis of High Strength Steel CT-110 under Cyclic Loading: Numerical and Experimental Research

  • 期刊论文

  • 发表日期：

    2025年10月21日

查看全文
  • Zhaoming Zhou,
  • Yuheng Zou,
  • Huaibing Chen,
  • Hui Liu,
  • Xiude Lu

摘要

Abstract

The diameter increase and wall thickness thinning of coiled tubing (CT) are easily caused by plastic deformation, which seriously affects the service fatigue life of CT. Currently, the basic data of the CT fatigue life model are obtained from field operation and fatigue testing machines. Among them, the test procedure for the CT fatigue testing machine is complicated and wastes sample CT. As the research object CT-110, this work established a theoretical model of CT low-cycle fatigue life based on shaping strain. A numerical calculation model of the coupling relationship between CT fatigue life and cycle count is established based on the finite element method (FEM). Finally, experimental verification is carried out. The results show that the material on the compression and tension sides of the CT flows in the direction of the neutral axial, which leads to a significant thinning of the wall thickness of the CT under tension and compression. However, the material at the neutral axis is not subjected to plastic strain. Hence, the maximum plastic strain and fatigue-sensitive area of CT appear on the axial tensile plane and compression plane, which is consistent with the field failure of CT. The elastoplastic finite element (FE) results showed good agreement with experimental results. The numerical results make up for the inaccuracy of theoretical and experimental calculations in predicting the fatigue life of CT. The analysis results provide theoretical guidance for the prediction of CT fatigue life in actual operation, and it can provide a reference for field operators to effectively avoid economic losses caused by misoperation.