Lightweight Design Of Multi Objective Topology For Space Reflector Strengthening Structure

The demand for space exploration is increasing,and the aperture of main reflector of the space camera has been put forward more requirements.However,the increase of reflector aperture causes the increase of reflector deformation and the increase of emission cost.Therefore,how to reduce the quality of the reflector under the premise of ensuring the performance of the reflector has gradually become an important research topic in the space field.In order to meet the requirements of the surface figure accuracy,natural frequency and light weight,based on the multi-level optimization and multi-objective optimization theory,the layout of the reflector substrate structure is optimized.The mian contents as follows:First of all,the reflector solid model is established,analysis the main working conditions,determine the loads and boundary conditions.The static analysis,modal analysis and impact response analysis of the reflector are done.Based on this analysis confirms the performance constraint indices of lightweight.Secondly,take the reflector structure compliance minimum as the goal,take the maximum displacement of reflector surface node and the first-order natural frequency as the constraints,establishes a mathematical model of shape optimization of reflector surface structure,and shape optimize of the matrix strengthen structure has done.Then,the compromise programming method was adopted to define the multi stiffness topology optimization objective function.The objective function of topology optimization of natural frequency is defined by the average frequency.The weight coefficient of each sub goal is defined by tolerance method.The Objective function of multi objective topology optimization based on compromise programming method and variable density interpolation.The topological structure of the reflector is obtained by referring to the results of topography optimization and topology optimization.Finally,the static stiffness and the first order natural frequency of reflector as the object,with the maximum of displacement node and the range of strengthen thickness as the constraint condition,compromise programming method to construct the objective function of multi-objective size optimization.Based on the compromise programming method,the objective function of multi-objective size optimization is constructed.According to the characteristics of the constraint and the objective function,the local approximation method is proposed to solve the optimal solution of the design parameters.And then update the size of the model,by finite element analysis,we can see that its performance to meet the design requirements,its quality compared to the original structure reduced by 7.2%,to achieve a lightweight design.