Pretension Design Of Cable-network Reflectors For Form Accuracy And Stiffness Requirements

The deployed cable-nework antenna reflectors are typical flexible tension structures.Different from other traditional structures they find their forms and structural stiffness from the self-equilibrium state of the cable-network structure.Hence,pretension design plays a vital role in achieving those surface accuracy and stiffness requirements.The whole dissertation is organized as follows:Firstly,the determining process of the initial configuration of the cable net is studied.A method based on projection theory and region segmentation treatment is proposed which can contain multiple constrains,when we generate the initial configuration.The optimal pretension design of several structural typed cable network structure is studied.It is based on the FDM and projection strategy.Several numerical examples proved the effectiveness of the proposed approaches.Secondly,the pretension design of cable network structure considering the flexible deformation of the supporting truss is studied.Based on nonlinear FEM and a decoupling treatment,a multi-step pretension design strategy is proposed.Pretension ratio of boundary cable element and maximum deformation of the supporting truss can be included as constraints.A group of initial pretensions for the coupling calculation are attained and applied to satisfy the convergence of the iterative calculation of coupling deformation.Thirdly,a novel stiffness design method of cable network with the determined forms is proposed.The elastic modulus of cable element is taken as the dynamic optimization design variables.By controlling the initial length of the cable element,the pretension design results of the whole structure can be maintained.Some practical approach based on substructure analysis and simulation verification is presented.