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<p>The material heterogeneity and structural discontinuity of welded rail joints in high-speed railways make them vulnerable to fatigue damage under wheel–rail rolling contact. In this study, a three-dimensional finite element model of a 1380&#xa0;MPa carbide-free bainitic rail welded joint was developed, and the fatigue damage behavior was assessed using the Findley critical-plane multiaxial fatigue criterion. The results show that the welded joint causes pronounced stress concentration, with the peak contact stress increasing from approximately 1000&#xa0;MPa in the base metal to about 1120&#xa0;MPa near the weld center. Fatigue damage is mainly concentrated in the weld zone and gradually decreases along the longitudinal direction toward both sides. The maximum fatigue damage occurs in the subsurface region approximately 2–3&#xa0;mm beneath the rail surface. As the wheel load increases from 80 kN to 120 kN, the fatigue damage in the weld zone increases markedly. A clear coupling effect between wheel load and friction coefficient is also observed, indicating that higher wheel loads and friction coefficients accelerate fatigue damage accumulation. These findings identify the weld zone as the most fatigue-critical region under rolling contact loading and indicate that the subsurface layer at a depth of 2–3&#xa0;mm is the preferential site for fatigue crack initiation. The results provide a useful reference for life assessment and maintenance management of welded rail joints in high-speed railways.</p>

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Study on the rolling contact fatigue damage mechanism of welded rail joints in high-speed railways: based on a multiaxial fatigue damage model

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年7月4日

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  • Zhicong Zhao,
  • ZhenKun Gao,
  • WenHui Gao,
  • Zhengrong Ni,
  • Qianli Zhou

摘要

The material heterogeneity and structural discontinuity of welded rail joints in high-speed railways make them vulnerable to fatigue damage under wheel–rail rolling contact. In this study, a three-dimensional finite element model of a 1380 MPa carbide-free bainitic rail welded joint was developed, and the fatigue damage behavior was assessed using the Findley critical-plane multiaxial fatigue criterion. The results show that the welded joint causes pronounced stress concentration, with the peak contact stress increasing from approximately 1000 MPa in the base metal to about 1120 MPa near the weld center. Fatigue damage is mainly concentrated in the weld zone and gradually decreases along the longitudinal direction toward both sides. The maximum fatigue damage occurs in the subsurface region approximately 2–3 mm beneath the rail surface. As the wheel load increases from 80 kN to 120 kN, the fatigue damage in the weld zone increases markedly. A clear coupling effect between wheel load and friction coefficient is also observed, indicating that higher wheel loads and friction coefficients accelerate fatigue damage accumulation. These findings identify the weld zone as the most fatigue-critical region under rolling contact loading and indicate that the subsurface layer at a depth of 2–3 mm is the preferential site for fatigue crack initiation. The results provide a useful reference for life assessment and maintenance management of welded rail joints in high-speed railways.