The fatigue design of railway axles requires that the stresses arising in the axle in real service are accurately quantified. This paper describes a method to compute the dynamic stresses arising in railway axles as the effect of train-track interaction. The method is based on the numerical simulation of the dynamic interaction between a flexible wheelset, and a flexible track. The wheelset is modelled as a flexible rotating body, using an Eulerian approach to take advantage from axial symmetry and modal synthesis to reduce the size of the problem. The track is modelled as an infinite periodic system, with the rail modelled as a Timoshenko beam resting on discrete elastic supports, considering the inertia associated with the sleepers. The numerical simulation considers the effect of geometric irregularities appearing on the rail and wheel surfaces, allowing to consider the effect of e.g. wheel polygonalisation and/or rail corrugation. From the results of the numerical simulation process, the dynamic displacements of the wheelset are finally extracted and processed to derive the dynamic stresses in the axle. The paper presents an application of the proposed procedure to the calculation of the dynamic stresses caused in the axle by a wheelflat and by rail corrugation, comparing the results obtained for the flexible wheelset with the case where wheelset flexibility is neglected, showing the importance of considering wheelset flexibility to capture the high-frequency contents of the stresses.
Numerical estimation of stresses in railway axles using flexible wheelset-track models
MAZZOLA, LAURA;BRUNI, STEFANO;
2011-01-01
Abstract
The fatigue design of railway axles requires that the stresses arising in the axle in real service are accurately quantified. This paper describes a method to compute the dynamic stresses arising in railway axles as the effect of train-track interaction. The method is based on the numerical simulation of the dynamic interaction between a flexible wheelset, and a flexible track. The wheelset is modelled as a flexible rotating body, using an Eulerian approach to take advantage from axial symmetry and modal synthesis to reduce the size of the problem. The track is modelled as an infinite periodic system, with the rail modelled as a Timoshenko beam resting on discrete elastic supports, considering the inertia associated with the sleepers. The numerical simulation considers the effect of geometric irregularities appearing on the rail and wheel surfaces, allowing to consider the effect of e.g. wheel polygonalisation and/or rail corrugation. From the results of the numerical simulation process, the dynamic displacements of the wheelset are finally extracted and processed to derive the dynamic stresses in the axle. The paper presents an application of the proposed procedure to the calculation of the dynamic stresses caused in the axle by a wheelflat and by rail corrugation, comparing the results obtained for the flexible wheelset with the case where wheelset flexibility is neglected, showing the importance of considering wheelset flexibility to capture the high-frequency contents of the stresses.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
