Free vibration behaviour of helically wound cylindrical shells

Buckling loads, free vibrations and vibrations with initial in-plane stresses for moderately thick, simply supported rectangular laminates resting on elastic foundations such as the Pasternak type. are examined in this paper. The analysis is carried out considering unsymmetric flat laminates subjected to biaxial compression and shear loads. First-order shear deformation theory, in conjunction with the Rayleigh-Ritz method is used for the evaluation of buckling loads and vibrations by means of a standard eigenvalue procedure. A large numerical investigation is intended to demonstrate the influence of laminate parameters (fiber orientations. degree of anisotropy. number of layers) and foundation parameters (modulus of subgrade reaction and shear modulus): the results obtained are reported and discussed in the paper. © 1999 Elsevier Science Ltd. All rights reserved.