Research On Muti-stable Unsymmetric Composite Laminates

Unsymmetric composite laminates have several stable configurations,which can be converted from one configuration to another by an excitation.Unsymmetric laminates are important alternative configurations for variant structures.Accurate prediction of the multistable configuration of unsymmetric laminates plates is important to the practical application of this structure.This paper establishes a displacement analytical model for unsymmetric laminates.After verifying the validity of the model,the influence of the model on the parameters of unsymmetric laminates is studied.Based on the analytical model of general unsymmetric laminates,this paper studies the analytical model of combined unsymmetric laminates,and verifies the validity of the analytical model by comparing with the results of finite element method.Research contents are as follows:This paper establishs an analytical model based on high-order polynomial function.Based on the principle of minimum potential energy,a new displacement model is solved by Rayleigh Ritz method and Newton iteration method.At the same time,the bi-stable mechanism of composite laminates was simulated ABAQUS.Several representative layers are selected for calculation.Based on the FEM results,the accuracy of the higher order displacement field function is verified by comparing the displacement field results in this paper with those in the literature.The influence of in-plane dimension,out-of-plane dimension and ply angle on the bistable configuration and the difficulty of jumping between configurationsis is discussed.At the same time,the conditions for the emergence of bistable configurations are explored.The analytical model is adjusted to fit the boundary conditions of combined unsymmetric laminates.The stable configuration of laminates is predicted by using the adjusted analytical model.The stable configuration was also analyzed by ABAQUS.The validity of the adjusted analytical model is verified by comparing the results of FEM analysis with those of theoretical calculation.Some special composite unsymmetric laminates are analyzed,and the influence of the angle of lamination on the stable configuration number is discussed.