Form-finding Method And Cutting Pattern For The Cable-reinforced Membrane Structure

This dissertation is made up of four parts: the first one is the material and making method of membrane structure; the second is form-finding analysis; the third is cutting pattern finding; the fourth is tension anchor design.The material and making method of membrane structure is different from ordinal structures, this thesis summaries those points and gives some useful conclusions.There are several methods in form-finding analysis such as dynamic relaxation method; force density method; nonlinear finite element method; key points imminence method; paralleling method; minimum surface method etc. Each method has it's advantages and disadvantages. The synthetical method for form finding of cable-reinforced membrane structures is proposed in this paper. In order to find the minimum surface of membrane structures, firstly the force density method is adopted to get approximate surface, then the dynamic relaxation method is used on the approximate surface to get an accuracy surface. It's proved that the synthetical method is workful through some examples.Cutting pattern finding includes cutting lines obtainment; curve surface into plane. A method is proposed for geodesic lines generation by nonlinear element method in cutting pattern for cable-enforced membrane structures. The minimum potential energy principle is applied to prove that the balance location of equal-tension geometrical nonlinear cables is the geodesic line when it slides freely on membrane surface. The method to obtain the geodesic line in cutting pattern for cable-enforced membrane structures has good convergence and calculation speed. Severial flattening mathod are studied and some examples are given.The tension anchors are widely used in the tensile membrane structure. The thesis summarizes the anchors and gives many useful equations.