In materials science, a composite laminate used in decks industry, is an assembly of layers of fibrous materials. The individual layers consist of high-modulus, high-strength fibers impregnated in an appropriate polymeric, metallic, or ceramic matrix material. Layers of different materials may be used, resulting in a hybrid laminate. The individual layers generally are orthotropic or transversely isotropic with the laminate then exhibiting anisotropic, orthotropic, or quasi-isotropic properties. Quasi-isotropic laminates exhibit isotropic in plane response but are not restricted to isotropic out-of-plane response. Depending upon the stacking sequence of the individual layers, the laminate may exhibit coupling between in plane and out of plane response. An example of bending-stretching coupling is the presence of curvature developing as a result of in-plane loading. The properties of a composite laminate depend on the geometrical arrangement and the properties of its constituents. The exact analysis of such structure - property relationship is rather complex because of many variables involved. Therefore, a few simplifying assumptions regarding the structural details and the state of stress within the composite have been introduced. The deformation of a plate subjected to transverse loading is caused either by flexural deformation due to rotation of cross-sections, or shear deformation due to sliding of sections or layers. The resulting deformation depends on the thickness to length ratio and the ratio of elastic to shear moduli. When the thickness to length ratio is small, the plate is considered thin, and it deforms mainly by flexure or bending; whereas when the thickness to length and the modular ratios are both large, the plate deforms mainly through shear. Due to the high ratio of in-plane modulus to transverse shear modulus, the shear deformation effects are more pronounced in the composite laminates subjected to transverse loads than in the isotropic plates under similar loading conditions.
