Practical technique for identifying spatial matrices of railway vehicle carbodies based on stationary excitation tests

Abstract

In order to investigate the vibration characteristics of railway vehicle carbodies, some sorts of analytical models have been proposed, such as simple beam, box-type, and finite element models. These models are constructed based on the equations of motions for some assumed or approximated structures. In this study, the authors utilize another modeling technique, without such assumptions or approximations. The model is based on the mass, damping, and stiffness matrices (spatial matrices) of the objective structure, which are identified with use of the frequency response functions (FRF) obtained in the stationary excitation tests. The method is firstly evaluated with a 4-degree-of-freedom system, and then applied to an actual railway vehicle carbody. It is confirmed that the identified spatial matrices properly represent the relation between the excitation force and response vibration even if the degree-of-freedom of the actual system is unknown. And also, the authors try to utilize the spatial matrices to estimate the effects of certain vibration reduction devices such as dynamic vibration absorbers attached to the carbody.

Keywords

• railway vehicle carbody
• spatial matrices
• frequency response function
• modal analysis
• stationary excitation test
• dynamic vibration absorber