VIBRATION OF LAMINATED PLATES WITH ADHESIVE JOINTS

The fundamental frequency of laminated plates with single-stepped lap joints was investigated analytically and experimentally. For the analy sis, a two-dimensional finite element code was developed and the funda mental frequencies of the laminated plates were extracted from the cal culation of the smallest eigenvalue. In the experiment, external excit ation was applied to the plates using an impact hammer. The frequency response functions of the laminated plates were obtained by a fast Fou rier transform function built in a dynamic signal analyser from which the fundamental frequencies were obtained. The fundamental frequency d ecreased as the thickness of the adhesive layer increased. When the st acking sequence of the composite laminates was [theta/-theta](2S), the fundamental frequencies decreased as theta increased. The analytical predictions were compared with experimental results. The fundamental f requencies of the laminated plates were closer to the results of plate s without adhesive joints when the difference between the Young's modu lus of the adhesive and the longitudinal modulus of the laminated plat es was decreased.