Dynamic analysis for laminated composite beams

The work presented in this paper is the theoretical and experimental investigation of the dynamic behavior for laminated composite beams (LCB). A finite element model is used in order lo obtain the natural frequencies and mode shapes of the LCB. The model includes separate rotational degrees of freedom for each lamina but does not require additional axial or transverse degrees of freedom beyond those necessary for a single lamina. The shape functions ensure compatibility between laminas. Shear deformation is included but not interfacial slip or delamination. The effect of the fiber orientation is considered. Numerical results are compared with the experimental ones. The experimental tests are carried out by using a hammer test and the frequency response function is displayed on FFT analyzer. The theoretical model gives good results compared with the experimental ones. It is found that the envelope layers have the main effect on the natural frequencies.1999 Published by Elsevier Science Ltd. All rights reserved.