ASSESSMENT OF COMPUTATIONAL MODELS FOR LAMINATED COMPOSITE PLATES

In this paper, results of the stress analysis of composite laminates subjected to mechanical load based on different higher order shear deformation theories are presented. Among the many equivalent single layer theories (ESL), the third-order shear deformation theory of Reddy is the most widely accepted model in the study of laminates. This model cannot represent shear stress continuity at the interfaces and zigzag nature of the displacement field. To improve the accuracy of transverse shear stress prediction, layer wise theories have proved to be very promising techniques. In all these theories, zero transverse shear stress boundary conditions at the top and the bottom of the plate are imposed. In many engineering applications, this requirement is not valid when the plate is subjected to shear traction parallel to the surface. To account for this, a displacement model which releases the zero transverse shear stress boundary condition is taken. The unconstrained third-order shear deformation theory (UTSDT) is useful where the boundary layer shear stress is significant. Navier solutions for bending and stress analysis of cross ply laminates are presented using layer wise model, unconstrained third-order shear deformation model and Reddy's ESL model, and compared with 3D elasticity solutions.