Optimization Design And Analysis Of Ring Deployable Antenna Cable Net Structure

This thesis selects loop-truss deployable antenna with a cable network as a research target, carried out a detailed analysis of the surface mesh design, cable mesh pretension design, precision adjustment methods and static mechanical properties of the system structure. The minimum principle error were proposed based on the AGRAWAL, and the equilateral triangle mesh projection of cable net mesh on the optical aperture of the antenna was applied in the division form of the cable mesh. The optimization configuration of the pre-stress was studied, using the method of bi-objective optimization and regarding RMSE of cable mesh accuracy and uniformity of force as the two objects, when comparatively studied the cable net pretension configuration considering the sag-to-span ratio and not considering the sag-to-span ratio, respectively. Meanwhile, axial error accuracy and defocus error are regarded as another two referred indicators based on the ideal paraboloid. Additionally, form-finding design method of considering truss deformation was given, obtaining the cable net initial design accuracy and stress configuration which most approaching the actual condition. As is shown in the numerical example, the above methods can get well cable mesh accuracy and unified force configuration.As the random error of the cable net appearing in the actual manufacture, the finite element analytical model of the cable net structure is built focus on the sensitivity research of different longitudinal cable on accuracy adjustment, getting the optimal adjustment cable. In addition to this, considering changes of the best adjustment cable length as the design variables, and cable mesh accuracy as the design object, the mathematical model of the cable mesh accuracy adjustment was built, proposing rapid optimization adjustment method to achieve cable mesh accuracy based on multi-dimensional retreat law. In the numerical results, this algorithm is much computationally efficient, increasing the cable mesh adjustment efficiency of antenna reflector, and improving the cable mesh accuracy of the reflector.For cable net system is susceptible to the random external force in the actual space environment, in this paper, a rebalanced finite element static analysis method when applied by external force based on the minimum potential energy principle. The geometry non-linear characteristics of the small cable deformation in large displacement was considered in this method, and calculated the numerical iteration results of structural finite model by Newton-Raphson method. The efficiency of this method is introduced in a specific example, and then the influence of different initial conditions on cable structural stiffness was assessed, through which it is found that better mechanical properties of the cable system could be obtained by increasing section size and pretension.The kinematic model of the flexible cable was built based on catenary for studying the kinematic properties of critical discrete particle of cable net when developing with the external annular truss. Numerical results show that the lateral traction velocity should be as low as possible in the developing process, which is able to make the movement of entire cable system stable with small impact. Also, the stiffness and modular analysis of the overall cable antenna structure based on the method of influence coefficient, and the obtained structure has a natural frequency of 2 Hz, which satisfy the minimum frequency requirements in actual antenna.