Vibrations of sandwich panels and beams with matrix cracks in the facings

The paper presents the solution of the vibration problem for sandwich panels and beams with matrix cracks in transverse layers of cross-ply facings. The closed-form solution is obtained by assumption that the panels can be characterized by the first-order shear deformation theory. The analysis accounts for a difference in the response of the facings with open and closed matrix cracks. Extension of the solution to the case of multi-skin panels is also discussed in the paper. In addition, the problem of vibration of sandwich beams with matrix cracks in the transverse layers and delaminations generating from the tips of transverse cracks is considered. As shown in this paper, although the presence of delaminations results in a larger reduction of the stiffness and free vibration frequencies than transverse cracking by itself, the changes in the frequencies remain relatively small.