SIMULATION OF HIGH-FREQUENCY VEHICLE TRACK INTERACTIONS

An effective time domain method for simulating the vertical vehicle-track interactions for low and high frequencies is presented. To be able to investigate the effects of local defects of the track leg voided sleepers) on contact forces and loads and long-term deterioration of track components, a discrete track model based on finite elements is necessary. The track model developed is extremely accurate and is able to consider irregularities and nonlinearities in the track structure. The number of sleepers to be considered is chosen so that the infinite extension of the track can be dealt with approximately. For excitation due to short wavelengths like short pitch corrugation or wheel flats, nonlinear contact mechanics has to be considered. The time-step integration algorithm is based on a modal decomposition of linear substructures and is therefore absolutely stable. The method includes the effects of moving masses and is valid for train speeds up to 500 mis. The capacity of the algorithm is demonstrated for different theoretical and practical examples.