An Experimental Modal Analysis Technique for Miniature Structures

Abstract

This paper describes an experimental modal analysis system which can effectively be used to obtain the modal parameters of small structures. The system uses an electromagnetic exciter to produce the excitation force, a piezoelectric transducer to measure this force, and a Laser Doppler Vibrometer to measure the response. Several designs of the magnetic actuator are discussed and evaluated. The system is verified by obtaining the modal parameters of a miniature cantilever plate, using two preferred exciter designs, and comparing the measured parameters with those acquired from a finite element model. Favorable agreement is obtained between the experimental and computational results. Finally, the two preferred exciters are compared and an optimal configuration is discussed.