Monday  |  Salon 14  |  05:50 PM–06:10 PM

#16635–Amplitude-dependent Modal Parameters Idenfication on Multiple-Output Structures with Close Natural Frequencies

Jointed structures have complex dynamic behaviour due to their amplitude-dependent properties. Several time-domain algorithms have been proposed to obtain modal properties of structures, provided that the contribution from different modes can be separated by means of bandpass filtering. However, this is difficult in many structures and impossible in some, for example in rotors. The work by Singh and Allen [1] is extended by applying such non-linear least-squares technique to a benchmark non-rotating structure with three close natural frequencies less than 4% apart. The potential advantage of multiple-output identification and the optimal time window length are studied. Based on the studies, it is better to combine the multiple-output data in a single least-squares fit, and the time window for parameter identification is recommended to be longer than “1 beating cycle”.

Sheng-Wei Tseng   National Chung Hsing University
Hugh Goyder   Cranfield University
Yum Ji Chan   National Chung Hsing University