Vibration of laminated plates with adhesive joints

Abstract

The fundamental frequency of laminated plates with single-stepped lap joints was investigated analytically and experimentally. For the analysis, a two-dimensional finite element code was developed and the fundamental frequencies of the laminated plates were extracted from the calculation of the smallest eigenvalue. In the experiment, external excitation was applied to the plates using an impact hammer. The frequency response functions of the laminated plates were obtained by a fast Fourier transform function built in a dynamic signal analyser from which the fundamental frequencies were obtained. The fundamental frequency decreased as the thickness of the adhesive layer increased. When the stacking sequence of the composite laminates was [θ/-θ]_2s, the fundamental frequencies decreased as θ increased. The analytical predictions were compared with experimental results. The fundamental frequencies of the laminated plates were closer to the results of plates without adhesive joints when the difference between the Young's modulus of the adhesive and the longitudinal modulus of the laminated plates was decreased.