PSI - Issue 75

Elena Sidorov et al. / Procedia Structural Integrity 75 (2025) 276–288 Elena Sidorov et al. / Structural Integrity Procedia (2025)

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In contrast to continuous rail welds, the stop-starts of the intermittent rail welds, that are subjected to longitudinal stresses, have additionally to be checked against fatigue. This check is beyond the scope of this paper. See further details in (Kuhlmann et al. 2022). In the aforementioned fatigue tests that were performed by Kuhlmann et al. (2022), only chain intermittent rail welds with a weld length of ℓ w = 50 mm could be investigated. Therefore, chain intermittent rail welds with a deviating weld length as well as staggered intermittent rail welds of any length are excluded from the application range of the newly proposed design recommendation in prEN 1993-6 (2024). In this paper, the influence on the weld pressure, that have not been considered up to now, is investigated in order to evaluate whether these influences are decisive and require a modification of the nominal stress formula. Particular focus is laid on the influence of unavoidable imperfections of the contact surface, deviating boundary conditions of the crane runway’s top chord (transverse stiffeners) and staggered intermittent rail welds.

Fig. 3. Overview on the design recommendations of prEN 1993-6 (2024) for the fatigue verification of rail welds subject to transverse normal stresses caused by wheel loads 3. Experimental investigations on contact surface imperfections 3.1. Introduction Ideal contact between the crane rail and the top flange of the crane runway beam cannot be achieved in practice due to the following reasons: (i) macroscopic imperfections of the members, for example spherical surfaces of rail and flange; (ii) microscopic imperfections in the form of surface roughness of rail and flange; (iii) thermal deformation of the members during welding, for example slight upward bending of the flange. For these reasons, the interaction at the interface between crane rail and flange was denoted as ‘technical contact’ in Sidorov & Euler (2024). Based on theoretical considerations, the implementation of a wedge-shaped gap under the rail with a maximum gap size of g con = 50 µm was proposed by (Sidorov & Euler, 2024) to simulate the technical contact for a numerical analysis with Finite Elements (FE). This proposal is validated by experimental investigations in the following. The contact between the rail and the flange is not only controlled by the gap size but also by the flange deformation. If the flange is exclusively supported by the web, it shows greater deformations as shown in Figure 4a in comparison to the case, where the flange bending is restrained by transverse stiffeners as shown in Figure 4b.