Decoupling Analysis And Solution Of Composite Sandwich Thin-walled Bar With Rectangular Section

Owing to the characteristics of high intensity ratio,high modulus ratio and light weight,composite structures have been applied abroad in many fields.Thin-walled bar is an important structure when being applied widespread.Furthermore,it will be one main form of composite bridge component in future.In the thesis,a general theoretical analysis the method of composite thin-walled bar is proposed,and on this basis, the method of analysis and solution for composite sandwich thin-walled bar is established.In the beginning,the paper makes some supplements and perfections for the calculation theory of composite thin-walled bar (composite thin-walled box girder) which documents[1~4] had put forward.Cylindrical shell theory with no bending moment is employed to analyze the mechanical behavior,the general constituitive equations are presented.Based on the principal of minimum potential energy,the equilibrium equations and corresponding boundary conditions concerned have been deduced. In addition,a solution to this issue is discussed.Secondly,according to the theory of composite thin-walled,a combination model of composite sandwich thin-walled bar has been set up.The deformation of three layers is described and the constitutive relationships are introduced,then the general potential energy function is found. Based on the principal of minimum potential energy, the equilibrium equations and corresponding boundary conditions of composite sandwich thin-walled bar have been deduced. Moreover, the elements of stiffness matrix are calculated specifically to equivalent constitutive equations of composite sandwich thin-walled box girder with rectangular section under the reasonable decoupling analysis.To derive the equilibrium equations and corresponding boundary conditions after being decoupled,besides,the process of solving for sandwich thin-walled box girder with rectangular section are given in different stress conditions.At last, self-compiled MATLAB program used to the analysis and calculation in case of axial tension,bending of composite sandwich thin-walled box girder with rectangular section,the several relevant curves with a reference value are received.