ASA 125th Meeting Ottawa 1993 May

1pSA8. A new technique for measuring structural dynamic response.

Mei Q. Wu

6682 Ganymede Rd., Mississauga, ON L5N 6R1, Canada

A modified cepstrum technique is introduced. It combines the cepstrum technique with an iteration procedure. The advantage of this technique is that it can determine the dynamic response of a structure from its vibration without any pre-knowledge of the excitation force. The restrictions of the technique are that it only applies to cases where the structural response is band limited in the frequency domain and the excitation force is short in time (comparing to the structural impulse response). When the structural response is not band limited, it can be determined in several limited frequency bands first and combined together later. In this paper, the theory of the modified cepstrum technique is reviewed, computer-simulated experiments are demonstrated, and an application example is presented. In the example, the magnitude of the structural dynamic response under 1400 Hz of a typewriter was determined by the modified cepstrum technique and compared to the dynamic response measured by conventional impulse excitation technique. The responses determined by the two techniques agreed well. [Work supported by IBM.]