Numerical analysis of the rail surface crack propagation under rail uplift force: A parametric study on initial crack geometry
Deokyong Sung, Seongwon Hong, Jaeik Lee
Abstract
Rail cracks initiate and propagate under wheel-rail interaction, which can lead to sudden rail fractures and even derailment. This study focused on the rail surface crack propagation with various initial crack geometries and angles under the rail uplift force induced by the wheel load. To simulate the extreme conditions, the location with the highest tensile strain was identified and determined as the initial crack location based on the three-dimensional finite element track model, and the stress intensity factors were calculated for 36 different cases with various geometries. The outcomes reveal that crack growth rates heighten with escalating loading cycles, especially for nearly vertical crack angles when the crack geometric ratio remains below 1 (denoting cases where crack width exceeds depth). Furthermore, KI and KII exhibit elevated values when the geometric ratio equals 1, surpassing the magnitudes seen at ratios of 0.25 and 0.5. Among these, a crack angle of 45° displays the highest results. These findings can contribute to estimating the approximate loading cycle at which the crack length propagates exponentially to develop preventative maintenance strategies.