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Contact stress comparison of the Base and Welded rail with different crystalline rearrangement.

Contact stress comparison of the Base and Welded rail with different crystalline rearrangement.

Source publication
Conference Paper
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The initiation and growth of fatigue cracking is mainly due to high-stress concentration, heterogeneity and poor quality of the weld. The detection and rectification of such weld defects are major concerns of rail network managers to reduce potential risk of rail breaks and derailments. To estimate the fatigue life of welded joints and to analyze t...


... Therefore, LEFM can be used in our calculations. It is also noteworthy that the use of LEFM has been common in previous studies dealing with cracks in rail structures, see for example works by Masoudi Nejad, 37 Endalemaw, 40 and Bogdanski et al. 41 All of the 7 cases of crack positions were analyzed, and their respective crack tip parameters were calculated and compared. The comparisons showed that for every pair of cases and wheel positions that were symmetrically similar, eg, case 1 (L = 7 cm) with D = 10 and case 7 (L = 53) with D = −10, there was only little difference between the values of parameters. ...
Finite element method is used to analyze a rail with a vertical bottom up crack at its foot, under the axle load and surface traction of a wheel. The possibility of crack formation at the foot of the rail in the neighborhood of a welding connection is discussed. A brief review on the importance of T‐stress in brittle fracture is presented. Seven cases with different locations of the crack relative to rail's sleeper contact region are considered. Numerous positions of the wheel are considered, and in each case, 3 crack parameters KI, KII, and T‐stress are calculated. Then, the biaxiality ratio and the mixity parameter for each loading and crack condition are calculated. It is shown that the location of crack and wheel can create mixed mode loading in the cracked rail and that the magnitude of crack tip parameters are strongly dependent on these geometric variables. In particular, the magnitudes of T‐stress and biaxiality ratio are significant in some cases. The effect of friction between the crack faces in the presence of compressive mode I loading on the mode II stress intensity factor is studied. Under mixed mode loading, due to the axle load and surface traction, the most critical condition is the formation of vertical cracks near the sleeper contact region.