An experimental modal testing/identification technique for personal computersA PC-based system for mode shape identification is evaluated. A time-domain modal identification procedure is utilized to identify the mode shapes of a beam apparatus from discrete time-domain measurements. The apparatus includes a cantilevered aluminum beam, four accelerometers, four low-pass filters, and the computer. The method's algorithm is comprised of an identification algorithm: the Eigensystem Realization Algorithm (ERA) and an estimation algorithm called Minimum Model Error (MME). The identification ability of this algorithm is compared with ERA alone, a frequency-response-function technique, and an Euler-Bernoulli beam model. Detection of modal parameters and mode shapes by the PC-based time-domain system is shown to be accurate in an application with an aluminum beam, while mode shapes identified by the frequency-domain technique are not as accurate as predicted. The new method is shown to be significantly less sensitive to noise and poorly excited modes than other leading methods. The results support the use of time-domain identification systems for mode shape prediction.
Document ID
19910050864
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Roemer, Michael J. (State Univ. of New York Buffalo, NY, United States)
Schlonski, Steven T. (State Univ. of New York Buffalo, NY, United States)
Mook, D. Joseph (New York, State University Buffalo, United States)