Experimental and theoretical investigations on nonlinear resonances of composite buckled microbridges

Abstract

Theoretical and experimental investigations have been conducted to study the nonlinear vibrations of a clamped–clamped beam with the effect of the initial deflection taken into consideration. A preliminary study analyzed the linear vibrations of a composite microcantilever beam. A very good agreement is found between theoretical and experimental values of the first three resonant frequencies of composite cantilever beams by taking into account the effect of the gold layer on the shift of the resonant frequencies. With this preliminary result, an exact solution is given to the linear problem associated with the nonlinear vibrations of initially buckled clamped–clamped structures using a direct analytical model. Several experimental multimode dynamic responses of composite buckled beams are also given to illustrate the validity and accuracy of this analytical model. Then, the influence of the interaction between resonant modes and the microstructure imperfections (nonideal boundary conditions, composite morphology, etc.) on the shift between the theoretical and experimental values of the resonant frequencies is considered.