Non-linear finite element analysis of composite panels

Abstract

In order to promote the efficient use of composite materials in civil engineering infrastructure, effort is being directed at the development of design criteria for composite structures. Insofar as design with regard to buckling of composite shells is concerned, it is well known that a key step is to investigate the influence of initial geometric imperfection on the non-linear behaviour of the composite shells. One possible approach is to use the validated numerical model based on the non-linear finite element analysis. Thus, the objective of this article is to present the formulation used in developing a composite shell element and to validate the element from the composite panels . The finite element used in the current study is an eight-noded shell element with six degrees of freedom per node. The non-linear formulation of the shell element is based on the updated Lagrangian method . The shell element is capable of small strain and large displacement analysis with finite rotations. In order to remove the rigid body rotation , a co-rotational method is used. The transverse shear deformation effects using the Reissner–Mindlin theory are included in formulating the linear and geometric stiffness matrix . Thus, the present composite shell element allows modeling of relatively thick composite plates and shells for both the linear and non-linear analyses. The validation of the composite shell element shows that the present results have very good agreement with existing references. Subsequently the postbuckling analyses for the modeling of the curved panel with initial imperfections are performed in order to investigate the effect of the initial geometric imperfection shape and amplitude. The results are used to estimate imperfection sensitivity for such panels.