Application of Experimental Modal Testing for Estimating Dynamic Properties of Structural Components

In this paper, experimental modal testing is used in relation to solving problems in railway engineerin. The railway engineering problem is related to identification of the dynamic properties of the railway track components in laboratory and in-situ conditions. This information is critically needed at the moment, in order to develop the Australian track model. In particular, the modal testing is applied to determine the dynamic stiffness and damping parameters of rail pads of various ages to investigate their degree of degradation with time in service. The frequency ranges used in the tests were different reflecting the range of resonant frequencies and mode shapes important for each specific element. For rail pads used in this study, the frequency range between 0 and 500 Hz is sufficient, while the beam-column elements require a frequency range from 0 to 2,000 Hz. The FRFs were obtained by exciting the specimens with an impact hammer. Bruel&Kjaer PULSE dynamic analyser was utilised for obtaining the FRF measurements and the STARModal package for extracting the modal parameters.