Transverse and vertical cracking behavior of railway rails due to geometrical imperfections and bending

Rail flaws and unexpected failures occurred at a quick pace as a result of the rapid growth of high-speed and heavy-haul railroads. It is of the utmost importance to prevent a situation like this since any possible breakdown of a rail carries the possibility of trucks being derailed devastatingly. As a consequence of this, there is a need for more sophisticated rail inspection, which involves the precise detection and assessment of rail problems in real-time. The purpose of this investigation is to provide an introduction to the most significant problems concerning the propagation of cracks and the fracture of rails. The loading conditions that fall under this category include contact forces from the wheel as well as residual stresses resulting from on-site welding and fabrication procedures. To ascertain the factors that led to the occurrence of fracture and failure damage, a series of tests were carried out. These tests included spectral, tensile, hardness and fracture toughness tests. Apart from the mentioned tests, fractographic analysis of the surfaces was investigated using a scanning electron microscope (SEM). Furthermore, stress distributions were ascertained, and the impact of residual stresses and geometric discontinuities on crack development was assessed using finite element modeling. The findings show that residual bending stresses considerably speed up fracture propagation, whereas stress concentration zones caused by geometric imperfections are strongly correlated with the beginning of cracks. In conclusion, the steps of crack propagation, beginning with the commencement of the crack and ending with the ultimate rupture, were described. According to the findings, stress concentration locations that are connected with geometric flaws have a significant role in the onset of cracks, while residual stresses contribute to the acceleration of fracture propagation.