Extensible Deformation Theory And Mechanism Of Composite Laminated Structure Considering Shape Effect

Smart materials such as composite material,piezoelectric material and shape memory alloy are used in the smart morphing structure to realize the transformation of structure.Among them,composite material,with the advantage of high specific strength,high specific modulus and light weight,has attracted a wide spread attention.The bistable composite laminated structure has two different stable equilibrium configurations.Each stable equilibrium configuration has certain rigidity without external and continuous loading.Therefore,it has good application prospect in the morphing structure field.According to the fabrication method,the bistable composite laminated structure can be divided into plate and cylinder type.For each type of composite laminated structure,the theoretical models to predict its bistability were proposed.However,the theoretical models were non-unified for both types.In addition,the bistability analyses were focused on the composite laminated structure with rectangular and elliptical shape.Considering these,research works on extensible deformation theory and mechanism of composite laminated structure considering shape effect are presented as follows:1.The unified uniform curvature analytical model to predict the stable characteristic of both types of composite laminated structure are proposed based on the extensible deformation assumption and nonlinear theory of plates and shells.Aiming at the specific initial curvature,the corresponding simplified analytical model is presented,with which the stable equilibrium configurations and critical condition of stable characteristic are theoretically forecasted.With combination of the initial natural curvature and inelastic curvature,the stable equilibrium configurations are qualitatively discussed through phase diagram.2.The uniform curvature analytical model are extended to non-uniform curvature analytical model,which considers the curvature vary linearly and quadratically.Based on the analytical models,the mechanisms of stable characteristic are investigated through the dimensionless stability characteristic curves and the factors affecting the stable characteristic of both types of composite laminated structure are discussed.3.On the basis of secondary development of Abaqus,the parametric modeling and automatic postprocessing plug-ins of plate and cylinder-type composite laminated structure are established.The parametric analyses of stable characteristic of both types of composite laminated structure include aspect ratio,single layer thickness,sidelength,angle of embrace,longitudinal length,angle of layup,layup number and temperature.They are quantitatively conducted with combination of analytical model and simulation from plug-ins.The results show that the plug-ins improve the research efficiency and the results from non-uniform curvature model correlate well with numerical results.4.The specimens of plate-and cylinder-type composite laminated structure with rectangular,elliptical,cruciform and other planform shapes are manufactured to validate the parametric analysis of stable characteristic.The shape effect of composite laminated structure is considered,and the limitation of analytical model and the error of experimental results are discussed.The results show that the change of planform shape of composite laminated structure affects the stable characteristic,and new equilibrium configurations are found.The above research provides a basis for the design and manufacture of composite laminated structure,and provides guidance for its practical application in morphing structure.