1Mechanical Engg. Dept., P. V. P. Siddhartha Institute of Technology, Vijayawada, A.P., India.
2Mechanical Engg. Dept., V. R. Siddhartha Engineering College, Vijayawada, A.P., India.
Several factors such as mismatch of Poisson's ratios and mismatch of coefficients of thermal expansion at the interface of two layers with different fiber angles, and coupling between shear, extension and bending due to unsymmetrical stacking of layers in generally orthotropic laminates influence the response of the laminated fiber reinforced composite structures subjected to complex state of loading. As there are several factors influencing the stresses, it is extremely difficult to estimate the exact reason for the variation of stresses unless the effect of each factor is known separately. In the present analysis an attempt is made to study the effect of fiber angle, which causes coupling between bending, shear and extensional deformations, on the behavior of an angle-ply laminated composite plate subjected to in-plane biaxial and out-of-plane transverse pressure loading. A finite element method which works on the basis of three-dimensional theory of elasticity is employed to evaluate the deflections, in-plane, out-of-plane and interlaminar stresses. The finite element software ANSYS 11.0 has been successfully executed for the validation of the finite element models. The results obtained by varying the fiber angle are discussed. Investigative studies reveal that the stresses increase up to certain value of θ and later decrease in case of in-plane biaxial loading due to the internal resistance developed at the interfaces of the layers with +θ and −θ fiber angles. The main reason for the internal resistance is due to the restriction of free longitudinal, transverse and in-plane shear deformations that produce due to the coupling effect. In case of out-of-plane transverse loading, σx and τzx decrease, and σy and τyz increase with fiber angle. This is mainly due to the change in internal resistance in the laminate with change in fiber angle. This analysis is very much useful in studying the effect of fiber angle alone on the static response of the composite structures subjected to in-plane biaxial and out-of-plane transverse pressure loading.
FEM, Angle-ply Laminate, Interlaminar stresses
