The Thermal Stress Analysis Method For Composite Structures

Based on three different theories, the finite element models are constructed for analysis of laminated composite plates subjected to thermal loads as well as the free edge effect. These work can be written as follows:1. An enhanced Reddy’s theory for laminated plate is proposed. Based on this theory, the four-node quadrilateral plate element is proposed for analysis of laminated composite plates subjected to thermal loads. Although transverse normal deformation is considered, the number of unknowns in the proposed model is the same as that in the Reddy theory. Numerical results show that the enhanced Reddy theory can accurately analyze the thermal expansion problems of laminated composite plates.2.Based on the enhanced global-local high-order theory(EGLHT-99), a four-node quadrilateral laminated plate element is presented, in which the interelement C0continuity condition and C1continuity condition are satisfied. The eight-node isoparametric element is used to construct the C0continuity displacement function, and in order to present the C1continuity displacement function, the rotation function of the discrete thin plate quadrilateral element DKQ is used. Numerical results show that the enhanced global-local higher-order theory is capable of treating free-edge problems in composite laminates under thermal expansion.3. This paper proposes an approach to improve C0global-local higher-order theory for thermal stress analysis of laminated composite plates. Transverse normal deformation has been considered in the proposed model, while the additional displacement variables have not increased. Based on this theory, six-nodes triangular elements are used to analyze the thermal expansion of laminated composite structures. Results show that GLHTC can accurately analyze the thermal expansion of the composite laminated plates, sandwich plates and multiplayer plates.