A high-order laminated plate theory with improved in-plane responses☆

In order to improve the accuracy of the in-plane responses of the shear deformable laminated composite plate theories, a new high-order laminated plate theory was developed based upon Reissner’s new mixed variational principle [Int. J. Num. Meth. Eng.20, 1366 (1984)]. To this end, a zig-zag shaped C0 function and Legendre polynomials were introduced into the approximate in-plane displacement distributions across the plate thickness. The accuracy of the present theory was examined by applying it to the cylindrical bending problem of laminated plates which had been solved exactly by Pagano [J. Comp. Mat.3, 398 (1969)]. A comparison with the exact solutions obtained for several symmetric and asymmetric cross-ply laminates indicates that the present theory accurately estimates in-plane responses, even for small span-to-thickness ratios.