Buckling and vibrations of unsymmetric laminates resting on elastic foundations under in-plane and shear forces

Buckling loads, free vibrations and vibrations with initial in-plane stress es 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 subject ed to biaxial compression and shear loads. First-order shear deformation th eory, in conjunction with the Rayleigh-Ritz method is used for the evaluati on of buckling loads and vibrations by means of a standard eigenvalue proce dure. A large numerical investigation is intended to demonstrate the influe nce of laminate parameters (fiber orientations, degree of anisotropy, numbe r of layers) and foundation parameters (modulus of subgrade reaction and sh ear modulus); the results obtained are reported and discussed in the paper. (C) 1999 Elsevier Science Ltd. All rights reserved.