For the experimental modal analysis of large structure where loss of excitation energy is expected, multiple excitation method is frequently used. In spite of many advantages, multiple excitation technique has yet some problems on treating many sets of data simultaneously and redundant information.
In this work, programs suitable for a personal computer is constructed to get multiple coherence function and frequency response function matrix from multiple sets of input/output data acquired from experiment.
Concurrently, a scheme, which treats redundant information contained in the frequency response function matrix and unifies inconsistent system poles for a mode, is presented. First, the above mentioned method and program are confirmed through simulation study of a 3 degree of freedom system. Then, single and multiple excitation tests on a lathe are executed and the measurement data are subsequently analyzed. Finally, some advantages; when using multiple excitation in modal testing, are shown through the investigation on the results obtained from above two experiments.
