The experimental characterization of wave propagation systems: II. Continuous systems and the effects of dispersion

This paper forms the second part of a study of the wave propagation approach and its application to the experimental characterization of structural/acoustic systems. It is shown that the measurement of time delays and attenuation factors by correlation techniques offers a useful complement to the measurement of frequency response in system characterization. Transient excitation is used and although the rapid frequency sweep is suitable for measurements in continuous systems, it is shown that the dispersion encountered in flexural wave propagation increases the difficulty in the interpretation of correlation data. To overcome this problem, another transient excitation signal is developed which has essentially single frequency content but which yields clear correlation functions, permitting the accurate measurement of group velocities at a single frequency.