BEHAVIOUR OF THE METAL OF RAILS AND WHEELS IN THE CONTACT ZONE. THREE-DIMENSIONAL PHOTO-ELASTIC STUDY OF A LOADED BUT NON-BENT RAIL
The behaviour of the metal of rails depends, to a large extent, on the magnitude and the distribution of the stresses in the vicinity of the contact surface between rail and wheel. The C 53 Committee has thus been assigned, as its first objective, to determine the stresses produced by the strains applied to the rail (or to the wheel). These strains comprise in particular: a vertical force, representing the action of the loaded wheel on the rail (and inversely); the bending of the rail resting on the sleepers or, equivalently, on an elastic body; the plastic deformations produced in certain regions of the rail (or of the wheel); these produce residual stresses which superimpose themselves on to those produced by the two first types of strains and on to those which may result from manufacture; the defects of the metal, which modify, in the vicinity of these, the stresses due to the preceding strains. Prof. Besseling and Dr. van Bommel plan to carry out these determinations mathematically, while making extensive use of modern calculation means. Interim Report No. 1 gave a detailed description of their calculation method and of its justification. With the same objective in view, Mr. Teissier du Cros and Mr. Radenkovic are carrying out some tests on rail and wheel models, the materials constituting these models having mechanical properties similar to those of steel (elastic and plastic deformations). Some photo-elastic tests are being carried out in the Laboratory of the Rolling Stock and Motive Power Department of the SNCF at Levallois. The purpose of these tests is to determine, on a reduced scale model of rail, the stress- distribution due to the first type of strains. Knowledge of this distribution will facilitate the calculations of Prof. Besseling. Moreover, when the accumulated plastic deformations have produced a system of residual stresses, which, owing to the consecutive passages of a sufficiently large number of rolling loads, has reached a state of equilibrium, so that this system does not change any longer after each subsequent load passage, one should, in order to determine the resultant stresses produced in the rail in the neighbourhood of a load, super-impose on the preceding residual stresses, the purely elastic stresses due to the action of the load and the bending of the rail (strains a and b). Their determination is thus an absolute requirement and the experimental method based on photo-elasticity can be used; it completes the modern mathematical calculation methods.
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International Union of RailwaysOffice of Research and Experiments
- Publication Date: 1965-10
- Features: Figures;
- Pagination: 15 p.
- TRT Terms: Car wheels (Railroads); Deformation; Deformation curve; Force; Rail (Railroads); Rail steel; Residual stress; Stresses; Structural tests; Tests; Train track dynamics; Wheels
- Old TRIS Terms: Question c53; Rail deformation; Rail dynamics; Rail metallurgy; Rail stress; Rail tests
- Subject Areas: Bridges and other structures; Railroads; Vehicles and Equipment;
- Accession Number: 00053184
- Record Type: Publication
- Source Agency: International Union of Railways
- Report/Paper Numbers: C53/RP 2/E Intrm Rpt.
- Files: TRIS
- Created Date: Jul 8 1994 12:00AM