• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2025, Vol. 61 ›› Issue (16): 102-115.doi: 10.3901/JME.2025.16.102

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Unified Analysis Method for High/Low Cycle Fatigue Behavior of Welded Structures Based on Structural Strain Parameters

LEI Linsen1,2,3, LI Xiangwei4, XING Shizhu5, LIU Xiaochao1, LI Yongzhe1, PEI Xianjun1,2,3   

  1. 1. School of Mechanical Engineering, Southeast University, Nanjing 211189;
    2. Key Laboratory of Structure and Thermal Protection of High Speed Aircraft, Ministry of Education, Nanjing 211189;
    3. Jiangsu Engineering Research Center of Aerospace Machinery, Nanjing 211189;
    4. CRRC Qiqihar Rolling Stock Co., Ltd., Qiqihar 161002;
    5. Naval Architecture and Ocean Engineering College, Dalian Maritime University, Dalian 116026
  • Accepted:2024-09-13 Online:2025-02-27 Published:2025-02-27

Abstract: Welded structures are experiencing increasingly stringent service conditions, enduring a mix of high- and low-cycle fatigue loads throughout their service life. A holistic approach to assess fatigue damage stemming from both load types is presented, expanding structural stress parameters to include the formulation of the structural strain parameter. A numerical technique is introduced, employing through-thickness resultant force and moment and accommodating three common structural lateral constraints: plane stress, plane strain, and predefined stress triaxiality factors. Simultaneously, three types of elastic-plastic hardening model are considered: linear hardening modulus, Ramberg-Osgood equation, and a customized stress-strain curve. Analysis of 872 sets of highand low-cycle fatigue data from welded structures with diverse base materials, utilizing the structural strain method alongside the master E-N curve, reveals the ability of equivalent structural strain parameters to correlate fatigue data across various materials. The equivalent structural strain parameter emerges as a universal fatigue metric, offering an effective foundation for comprehensive analyses on welded joint fatigue performance compared to the equivalent structural stress method.

Key words: low-cycle fatigue, high-cycle fatigue, welded structure, structural strain, fatigue parameter, master E-N curve

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