Analysis Of The Influencing Factors Of Stiffness Of Quadrangular Prism Tensegrity Structure

The tensegrity structure in the engineering field has the unique advantages of reasonable force and controllable shape.It has been widely concerned by various disciplines since its appearance,especially the direction of spatial structure.Because the tensegrity structure is a flexible large deformation structure with variable stiffness,its stiffness is easily affected by internal factors or external conditions.However,at present,the stiffness analysis of the tensegrity structure has not formed a systematic theory at home and abroad.Therefore,it is very necessary to study the regularity of the stiffness of the quadrangular prism tensegrity structure affected by different factors.In this paper,when studying the three influencing factors of the tensegrity structure,the analysis of the load-displacement curve,load-internal force curve,and load-stiffness curve is used to obtain the influence rule of stiffness,in order to provide a feasible way to find a new combination and provide a reference for the application of the tensegrity structure to the actual construction project.The specific research content is as follows:Firstly,the special stiffness formation mechanism of the tensegrity structure is explained by the expression of the tangent stiffness matrix.From the two aspects of the stiffness of the member and the stiffness of the structure,the total stiffness of the tensegrity structure is expressed as the sum of the elastic stiffness and the geometric stiffness.Secondly,according to the basic principle of the form-finding method,the advantages and disadvantages and their application of the force density method and the dynamic relaxation method are analyzed and compared.The MATLAB program compiled from the geometric parameters such as the node coordinate matrix and the structural topology matrix obtains the force density vector and the relationship of the initial prestress ratio of the basic configuration of the tensegrity structure,and the finite element model is established in ANSYS accordingly.Thirdly,taking the single-layer quadrangular prism tensegrity structure as the research object,the influence of prestress on the stiffness of the structure under two different restraint modes was explored.The effects of prestressing under the two modes of unconstrained restraint and full restraint at the bottom are compared and analyzed,and the influence of prestressing force on the stiffness of the single-layer tensile overall structure is obtained.It provides a reference for the application of a reasonable prestressing level to the tensegrity structure,so as to achieve the optimal load bearing performance of the structure and make it better use its variable stiffness characteristics.Fourthly,taking the single-layer quadrangular prism tensegrity structure as the research object,this paper explores the structural stiffness affected by the position of horizontal external load and the angle of horizontal external load without additional restraint.The influence of prestressing force on the stiffness of the single-layer tensegrity structure is obtained.Use this as a reference to minimize the adverse impact of horizontal loads on the structure in actual engineering.Finally,using the modular idea,the two quadrangular prism tensegrity structures are laminated and assembled in a node-to-node connection manner to form a double-layer quadrangular prism tensegrity structure.Through the stiffness analysis of the double-layer quadrangular prism tensegrity structure,the influence of the unit rotation direction on the stiffness of the tensegrity structure under the fully constrained bottom mode is obtained.