Influence of Stress Intensity Factor on Rail Fatigue Crack Propagation by Finite Element Method

Wheel rail rolling contact fatigue is a very common form of damage, which can lead to uneven rail treads, railhead nuclear damage, etc. Therefore, ANSYS software was used to establish a three-dimensional wheel-rail contact model and analyze the effects of several main characteristics, such as the rail crack length and crack propagation angle, on the fatigue crack intensity factor during crack propagation. The main findings were as follows: (1) With the rail crack length increasing, the position where the crack propagated by mode I moved from the inner edge of the wheel-rail contact spot to the outer edge. When the crack propagated to 0.3-0.5 mm, it propagated to the rail surface, causing the rail material to peel or fall off and other damage. (2) When the crack propagation angle was less than 30 degrees, the cracks were mainly mode II cracks. When the angle was between 30 and 70 degrees, the cracks were mode I-II cracks. When the angle was more than 70 degrees, the cracks were mainly mode I cracks. When the crack propagation angle was 60 degrees, the equivalent stress intensity factor reached the maximum, and the rail cracks propagated the fastest.

Automated summary

The study found that as the rail crack length increases, the position where the crack propagates by mode I shifts from the inner edge of the wheel-rail contact spot to the outer edge. When the crack propagates to 0.3-0.5 mm, it reaches the rail surface, causing the rail material to peel or fall off.