轻载长悬臂桁架结构的优化设计

The optimization design of long cantilever truss structure with light load

以轻载长悬臂桁架为研究对象,分析其受力特征,建立以结构总质量为优化目标,以结构强度、刚度、局部稳定性等为约束条件的数学优化模型;通过Design Exploration工具对局部求解区间内的弦杆与腹杆外径寻优求解,得到相同结构、不同载荷条件下的优化解及灵敏度分析图,结果表明:增大弦杆外径可有效提高桁架整体结构强度和刚度,但腹杆对结构刚度和强度的影响效果较复杂,该结论对结构改进与类似结构设计具有一定的指导意义。最后对优化求解后的桁架结构进行有限元分析,由最大组合应力云图和总变形云图可知,优化后的桁架能满足设计要求且结构材料得到了充分利用,该设计方法较传统设计方法效率更高、设计结果更合理。

Taking the long cantilever truss structure with light load as an example, it discusses its load character, builds the total quality of structure as the target, designs the constrain conditions such as structure strength, stiff- ness and local stability. Based on Design Exploration tool it obtains the outside diameters of bars and load optimi- zation solution and sensitivity under the different condition. The results show that increasing the diameter of bars can improve the overall truss structural strength and stiffness. Finally, it uses finite element analysis to give the optimal solution of truss structures. The maximum combined stress distribution curve and total deformation distri- bution curve illustrate that the optimized materials can meet the design requirements, the design method com- pared with the traditional design method is more efficient, the design result is more reasonable.