输出载荷精确控制的结构拓扑优化设计方法

Structure topology optimization method for output loads precise control

随着飞行器性能的不断提高,其承载结构的设计也越来越复杂.通过优化设计载荷的传递方式,将载荷合理分配到承载结构上,对充分利用材料的承载潜力、减轻结构重量以及保证承载性能具有重要意义.为此本文提出了一种对输出载荷精确控制的结构拓扑优化设计方法,可在给定载荷输入和边界条件下根据设计要求实现输出位置载荷大小的精确可控.通过在载荷输出位置设置辅助杆单元,将输出载荷约束转化为更加直观并易于建模的杆单元节点位移约束并加以精确控制,结合结构柔顺度设计目标、整体材料体积约束,建立了基于密度变量的拓扑优化设计新模型.文章通过数值算例验证了所提方法的有效性,并同时研究了优化设计结果随材料用量、输出载荷约束区间以及输出载荷比例等因素变化的规律.

With the improvement of the aircraft performance, the design of load carrying structures becomes more and more complicated. The input load should be distributed properly to the load carrying structure by the design of load path, which is of vital importance to make full use of load carrying capacity of the material, save the structural weight and ensure the load carrying capacity of the structure. For this reason, the purpose of this paper is to propose a new continuum structure topology optimization method that controls the output loads precisely. Under given input loads and boundary conditions,the magnitudes of the output loads are precisely designed to demanding values. To have a convenient modelling of the output load, we propose to apply some artificial bar elements at the output positions instead of standard boundary conditions. The constraints on output loads are then equivalently transferred to the constraints on nodal displacements of the bars, which are much simpler to be controlled. These constraints, as well as the design objective of minimizing structural compliance and the material volume constraints, formulate a new density based topology optimization model.Numerical examples tested in this paper have validated the effect of the proposed optimization scheme. The influence of the material usage, constraint bounds and ratio of output loads on the optimized design are also analyzed in details.