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Rails, Clips and Buffer Stops

Mechanical Stress Analysis of Rail Clip

This example shows the mechanical stress analysis of a temporary rail clip. The joint is subject to vertical loads at the rail head. Quarter- symmetry is utilised to reduce the overall size of the analysis. The objective is to establish the stresses in the clamping unit, when it is subject to both rail loads and loads from pre-tensioning of the clamping bolt.
1) The solid models of each part of the unit (rail, block, clip and spacer) are created by importing from CAD IGES files. These are then meshed with solid elements, the loads are applied and finally the models are substructured into superelements.

2) The individual superelements are merged into the overall model and frictional contact elements are generated between the mating surfaces. Hence the analysis is non-linear and requires an iterative process to achieve a converged solution.
3) Once analysed, the results are expanded back to each model to obtain the resulting stresses. (The results shown here are for the Tresca equivalent stress magnitude).
Structural Analysis of Buffer Stops
Structural Analysis Of Friction Buffer Stop
The analysis was performed for the buffer stop under 3 separate load cases, viz. with the OLEO oil-damped buffer stops under a compressive load of up to 120 kN and the buffer stop stationary, with the OLEO buffers fully retracted and the first stage buffer stop sliding under friction shoe control and finally with the buffer stop and all slave units sliding.
Structural Analysis Of Fixed Buffer Stop
The analysis was performed for the buffer stop under a unit buffering load applied to each of the front buffering tips. The purpose of the analysis was to determine the maximum safe buffering load that could be applied to the buffer stop, such that the buffer stop structure would not experience stresses that exceeded the material yield strength.
Structural Analysis Of Friction Buffer Stop
The analysis was performed for the buffer stop under 2 separate load cases, viz. first with the impact absorber units under a compressive load of up to 150 kN each , with the buffer stop stationary and second with the impact absorber units fully retracted and the buffer stop sliding under friction shoe control.
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