A New Locking Free Higher Order Finite Element Formulation for Composite Beams.

A refined 2-node, 7 DOF/node beam element formulation is presented in this paper. This formulation is based on higher order shear deformation theory with lateral contraction for axial-flexural-shear coupled deformation in asymmetrically stacked laminated composite beams. In addition to axial, transverse and rotational degrees of freedom, the formulation also incorporates the lateral contraction and its higher order counterparts as degrees of freedom. The element shape functions are derived by solving the static part of the governing equations. The element considers general ply stacking and the numerical results shows that the element exhibits super convergent property. The efficiency of the element in capturing both the static and dynamic inter-laminar stresses is demonstrated. The accuracy of the element to capture free vibration and wave propogation responses with small problem sizes is also demonstrated.