Static Analysis Method In Laminated Composite Structure

Composite is becoming a new kind of structural material due to its advantage of highstrength, light weight, corrosion resistance. During the engineering application, laminatedcomposite structures are easily damaged by interlaminar stress. Therefore, it is very necessaryto propose an accurate and efficient method which can predict interlaminar stress. In thispaper, static analysis method used in laminated composite beam and plate are to be studied.Firstly, a quadrilateral element based on the enhanced global-local higher-order theory isproposed to study the free-edge effect problems of laminates. The proposed theory satisfiesthe continuity condition of displacements and interlaminar stresses as well as free sheartraction conditions on the top and the bottom surfaces. In addition, the number of unknownvariables in the model is independent of the number of layers in laminates. The refinedfour-node quadrilateral element satisfies the requirement of C1weak-continuity conditions atadjacent elements. The numerical results show that the proposed quadrilateral element basedon the enhanced global-local higher-order theory is accurate enough for the free-edgeproblems of composite laminates subjected to extension loads.Secondly, this paper proposed a C0-type global-local higher-order beam theory byconsidering transverse normal thermal deformation, which is used to analyze thermalexpansion and bending problems of laminated composite structures. Although transversenormal strain was taken into account, additional displacement variables are not increased.First derivatives of transverse displacement have been removed from displacement field of theproposed model, so it is convenient to construct higher-order element based on the proposedmodel. The results show that the proposed model can accurately analyze the thermalexpansion and bending problems, whereas the models neglecting transverse normal strain areless accurate.