NUMERICAL MODELLING OF A 3D RAIL RCF 'SQUAT'-TYPE CRACK UNDER OPERATING LOAD

• Published in: Fatigue & fracture of engineering materials & structures Vol. 21; no. 8; pp. 923 - 935
• Main Authors: Bogda, S, Olzak, M, Stupnicki, J
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.08.1998; Blackwell Science
• Subjects: 3D FEM modelling; Applied sciences; Contact mechanics; Exact sciences and technology; Fatigue; Fatigue crack growth; Fatigue cracks; Fatigue failure; Fracture mechanics; Friction; Mathematical models; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Rail rolling contact fatigue; Rails; Stress intensity factors; Three dimensional models; Wheels; Roll contact fatigue; Finite element method; Stress intensity factor; Friction; Rail; Mechanical properties; Application; Modeling; Residual stress; Fatigue crack; Railway equipment; Crack propagation
• ISSN: 8756-758X; 1460-2695
• DOI: 10.1046/j.1460-2695.1998.00082.x

The analysis is based on the 3D FE model of the rail Rolling‐Contact‐Fatigue (RCF) ‘squat’‐type crack, which tends to be common in tracks with high‐speed passengers and mixed traffic. The model incorporates the section of rail and a wheel of real geometry, in which the wheel is rolling over the running band of rail containing the ‘squat’‐type crack. The state of stress in the vicinity of the crack front is determined, and consequently the values and ranges of the stress intensity factors (SIFs) KI , KII andKIII at the crack front are calculated for the cycle of rolling. To simulate loading conditions occurring in practice, residual, bending and thermal stresses acting in the presence of the tractive force were taken into account. The results indicate a significant role of face friction and tractive force in the loading mechanism at the ‘squat’. The longitudinal and lateral residual stresses may also influence the loading cycles, especially for the cases with reduced friction between the crack faces. Reduction of the face friction coefficient to values close to zero creates conditions for crack propagation driven by the shear mode mechanism. These results were obtained under a project sponsored by the ERRI D173 Committee, Utrecht, The Netherlands.