열차통행, 기온변화 및 잔류응력을 고려한 장대레일 테르밋 용접부 피로한계 추정

초록

This study presents a quantitative estimation of the fatigue limit of thermite weld joints in continuous welded rails (CWR) based on linear elastic fracture mechanics (LEFM). Bending stresses were derived from field measurements on the Gyeongbu High-Speed Line, while thermal and residual stresses were evaluated using 2024 Seoul temperature data and previous studies. Fatigue limits were estimated using the Barsom & Rolfe approach considering the combined effects of bending, thermal, and residual stresses with initial crack sizes of 0.6 mm and 1.0 mm. The resulting fatigue limits ranged from 36 MPa to 116 MPa, showing higher limits during compressive thermal stress periods (June？September) and lower limits during tensile stress periods (January？May). These findings provide a rational basis for performance-based maintenance and fatigue life assessment of thermite-welded rail joints in high-speed railways.

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