正放抽空四角锥平板网架结构的优化

Optimization of quadrangular pyramid flat grid structure

借助大型通用软件ANSYS和MATLAB,以上弦中心、外围杆件,下弦杆和腹杆的截面尺寸为多设计变量,在不同网格尺寸下,同时以网架高度及四类杆件截面尺寸为组合设计变量,均以结构耗钢量最小为优化目标,利用遗传算法和模拟退火算法,探究不同设计变量优化对结构耗钢量的影响。结果表明:在相同初始设计条件下,组合设计变量优化效果远优于多设计变量,其最优耗钢量为38.49;遗传算法和模拟退火算法均能实现结构的优化,但遗传算法优化精度一般要高于模拟退火算法,而模拟退火算法优化效率要高于遗传算法;在进行结构设计时,网格尺寸选取应适宜,不宜过大或过小。

With the help of ANSYS and MATLAB,the design variables are the centre and peripheral members of the upper chord,the cross-sectional dimensions of the lower chord and the web,and the height of the grid and the cross-sectional dimensions of the four types of bars are combined as design variables under different grid sizes.The results show that the structural steel consumption is minimised under the same initial design conditions.The results show that:under the same initial design conditions,the combined design variables are much better than multiple design variables,and the optimal steel consumption is 38.49 tonnes;both the genetic algorithm and the simulated annealing algorithm can optimise the structure,but the optimization accuracy of the genetic algorithm is generally higher than that of the simulated annealing algorithm,and the optimization efficiency of the simulated annealing algorithm is higher than that of the genetic algorithm;when designing the structure,the mesh size should be selected appropriately,and should not be too large or too small.