基于二级多点逼近算法的航天器结构优化设计

Structural optimization of spacecraft based on two-level multi-point approximate method

在某新型卫星结构研制的初样阶段,建立了卫星初始设计的有限元模型.以主承力桁架结构中各梁的截面尺寸为设计变量,考虑整星模态频率和强度约束,建立了以结构重量最轻为目标的优化模型.应用二级多点逼近优化算法进行了结构优化计算,在每一个计算周期中,原结构优化问题先转化为具有较高精度的第1级多点近似问题,该问题则通过可由对偶法快速求解的第2级近似问题逼近.经过初步试算、设计改进和再优化3个阶段,设置并进行了一系列的优化计算,逐步明确了设计的方向和各结构参数的取值范围,得到了合理的可行方案,为该卫星平台结构初样的详细设计提供了参考,同时表明所采用的优化方法适用于工程结构优化问题.

At the primal design stage of a new satellite,finite element model of the initial structure was established.Taking thicknesses of pipe beams and rectangle thin-wall beams as design variables,and considering constraints of natural frequency and strength,a structural optimization model was developed to approach minimum mass.Two-level multi-point approximation method was applied in structural optimization.In each calculation cycle,the original optimization problem was transformed to a first level multi-point approximate problem,and it was also approached by a second approximate problem which can be quickly solved by dual method.Three stages were implemented in the whole optimization process： initial optimum searching tests,design revision and re-optimization.Among the first stages,five runs were set with different constraints,design variables bounds and structural centroid heights,through which the design direction and interval of various structural parameters were obtained.Then the original structure was revised according to the results of the first stage.A new optimization model with fewer design variables and more reasonable variables bounds is established in the third stage and a feasible design is achieved,which provide references to detail design of the satellite structure.It indicates that the applied design procedure and optimization method are effective in engineering structural optimization problem.