Ingo Kaiser

Interaction of elastic wheelsets and elastic rails: modelling and simulation

The model of a railway vehicle running on a straight track is presented, in which the wheelsets and the rails are modelled as elastic bodies. The influence of the structural elasticities of the wheelsets and the rails on the running behaviour, especially the hunting motion of the vehicle, is investigated.

Refining the modelling of vehicle-track interaction

An enhanced model of a passenger coach running on a straight track is developed. This model includes wheelsets modelled as rotating flexible bodies, a track consisting of flexible rails supported on discrete sleepers and wheel–rail contact modules, which can describe non-elliptic contact patches based on a boundary element method (BEM). For the scenarios of undisturbed centred running and permanent hunting, the impact of the structural deformations of the wheelsets and the rails on the stress distribution in the wheel–rail contact is investigated.

Modeling and Simulation of the Mid-Frequency Behaviour of an Elastic Bogie

Some effects occurring at modern high speed railway vehicles like grumbling noise and polygonalization of the wheels are located in the mid-frequency range between 50 Hz and 500 Hz. Since multi-body systems consisting of rigid bodies are not sufficient for this frequency range, a description of the rotating elastic wheelsets is developed in this paper. This description results in linear differential equations with constant coefficients and provides a very simple investigation of the vehicle and an easy integration into a complete vehicle-track model.

Bridging the Gap from Multibody Simulations to Acoustic Analysis

Multibody simulation plays an essential role in the initial design phase of railway vehicles in which conceptual issues are investigated. It is as well the state-of-the-art method in order to study and optimize the running dynamics and comfort of railway vehicles in details. However, acoustic issues could not be ad ressed so far by multibody analysis. This is due to the fact that the validity of the used multibody models is restricted to the very low frequency range. In addition, multibody methodology is not prepared to evaluate acoustic measures in order to assess a railway vehicle under consideration.

The impact of structural flexibilities of wheelsets and rails on the hunting behaviour of a railway vehicle

ABSTRACT The hunting motion of a passenger coach is investigated using a multibody system in which the wheelsets and the rails can be modelled as flexible bodies. By comparing the results for different model variants, in which the structural flexibilities of the wheelsets and of the rails are either taken into account or neglected, the impact of the flexibilities is analysed. It turns out that the flexibilities of both the wheelsets and the rails have a significant impact on the hunting behaviour by increasing the lateral motions of the wheelsets and lowering the critical speed. In order to investigate the impact of the flexibilities under different operating conditions, the calculations are carried out for track geometries using different rail profiles (60E1, 60E2) and different rail cants (1:40, 1:20) and for different values for the friction coefficient (0.25…0.4) at the wheel–rail contact. The results show that the influence of the flexibilities is the strongest for high lateral forces, which occur e.g. for contact geometries leading to high hunting frequencies and for high values of the friction coefficient. The results also show in some cases a strong impact of the flexibilities on the position of the wheel–rail contact on the running surface of the rail, which is of particular interest with respect to wear simulation.