Displacement and stress response of laminated beams and stiffened plates using a high-order element

Abstract

In this paper several aspects of displacements and stresses in laminated composite beams and stiffened plates have been studied. To give due importance to the shear deformations in composite plates, a high-order theory has been developed. A comparison between the results using the first-order theory and the higher-order theory has been presented. The element has been developed using the quadratic isoparametric shape functions. Therefore, it can accommodate curved boundaries. Moreover, the stiffener element can have an arbitrary planform and it need not pass through any nodal point. The stiffener element has been developed in such a fashion to make the mesh division free from the location of the stiffener. This is extremely advantageous for optimization of the path of the stiffener in a stiffened plated structure, while it is not necessary to modify the mesh division whenever the stiffener path is modified. Most research works on stresses in composite plates report stresses at the Gaussian integration points. However, a designer is more interested in the stresses at the nodal points. A special smoothing technique has been employed to evaluate the stresses at the nodal points.