The 'Rail-Unloading' Problem deals with a heavy beam of infinite or semi-infinite length, which is placed on both sides of a supporting point on planes with different levels. The rail is lifted from a wagon platform by an amount of hl on the left side. On the right side the rail is placed on the ground for later mounting by lowering it by an amount of hr. The main goal is to be safe from plastification of the rail, which makes it necessary to know the maximum bending moment in the rail. The rail itself can be assumed as an infinitely long, heavy beam. Defining the system as a bending beam with two spans, i.e. segments between the supporting point and the plane contact points on both sides, the integration of the differential equations for beam bending requires the determination of integration constants from the boundary conditions of the right and the left span. Two different situations are examined. In the first case, at the beginning of the unloading process, the right end of the rail does not contact the ground yet. In the second case the rail is placed on the wagon platform and on the ground without any jump in the curvature. An analytical expression is presented for the dependence of the maximum bending moment on the ratio of the unloading levels as well as its location and the relationship between the right span length and the right unloading level. The analytical solution, which is based on the assumption of small strains and small curvature, was verified by finite element simulations.
The "rail-unloading" problem
Analytische Lösung des Biegeproblems bei der Verlegung von Eisenbahnschienen
Technische Mechanik ; 22 , 4 ; 317-321
2002
5 Seiten, 2 Bilder, 1 Quelle
Article (Journal)
English