Structural Safety, 6 (1989) 115-127 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands 115 RANDOM RESPONSE OF ANTISYMMETRIC ANGLE-PLY LAMINATED PLATES * M.P. Singh, A.A. Khdeir, G.O. Maldonado and J.N. Reddy Department of Engineering Science and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (U.S.A.) Key words: composite plates; laminated plates; random vibration; random response; thick plates; shear deformation; first-order theory; random excitation; random field. ABSTRACT The random response of an antisymmetric angle-ply composite plate subjected to random lateral load on its surface is obtained The first-order transverse shear deformation theory, involving five coupled partial differential equations, is used. To evaluate the effect of shear deformation, anisotropy and other problem parameters on the response, the numerical results obtained with this theory are compared with the results obtained by the classical plate theory. Significant differences are observed in the two sets of results obtained by the two theories especially for thick plates, thus demonstrating the importance of shear deformations and need for utilization of plate theories which properly account for such deformations. 1. INTRODUCTION In high-performance systems, composite plates made with several layers of high-strength lamina are often used. Depending upon the orientation of the fibers in the various layers, the composite plates are often classified as cross-ply or angle-ply laminates with symmetric, antisymmetric or asymmetric layouts. Cross-ply laminates are those with laminae oriented at 0 o and 90 o to the laminate (or plate) axes, whereas angle-ply laminates are made of laminae with orientations other than 0 ° and 90 °. Such plates usually exhibit significant anisotropy. The response of these plates is also significantly affected by the transverse shear deformation, because of their low transverse moduli compared to the in-plane moduli. As a result, the classical plate theory based on Kirchhoff's hypothesis fails to predict the response of such composite plates correctly. To incorporate these effects, therefore, the first and higher order theories have been proposed by Mindlin [1], Yang et al. [2], Reddy [3], etc. * Paper presented at an International Symposium on Methods of Stochastic Mechanics and Applications, Urbana, IL, U.S.A., October 31-November 1, 1988. 0167-4730/89/$03.50 © 1989 Elsevier Science Publishers B.V.