Research on shape optimization of free-form surface reticulated shell structure based on nodal well-formedness
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摘要: 为获得形式自由且受力性能合理的自由曲面单层网壳结构形态,以单位力作用下的位移响应作为结构连接性能的衡量参数,同时为保证结构曲面的光顺性引入NURBS技术,基于考虑荷载作用的结构节点构形度评价指标,提出了相应的自由曲面结构形态优化方法。将结构控制点的坐标作为优化变量,节点构形度最小值的最大化作为优化目标,综合结构总用钢量、最大节点位移和构件长细比等约束条件,采用遗传算法对结构的曲面形态进行优化。结果表明,节点构形度可以准确反映节点的连接性能,采用遗传优化算法优化结构的曲面形态,可获得杆件以受轴压为主的结构形态,受力模式得到有效改善,受力合理,保证了结构极限承载力及其安全性。Abstract: In order to obtain the free-form and reasonable mechanical properties of the free-form single-layer reticulated shell structure,the displacement response under the action of a unit force was taken as the measurement parameter of the structural connection performance,and NURBS technology was introduced to ensure the smoothness of the structural surface.Based on the evaluation index of the nodal well-formedness under load,the corresponding optimization method of the free-form surface structure is proposed.Taking the coordinates of structural control points as the optimization variables and the maximization of the minimum nodal well-formedness as the optimization objective,a genetic algorithm was used to optimize the surface shape of the structure by considering the constraint conditions such as total mass of the steel material,the maximum node displacement and the slenderness ratio.The results show that the nodal well-formedness can accurately reflect the joint connection performance,and the genetic algorithm can obtain the structural shape of the rod mainly subjected to axial compression.The stress mode is effectively improved,the stress level is reasonable,and the structure’s ultimate bearing capacity and safety are guaranteed.
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Key words:
- free-form surface /
- shape optimization /
- NURBS surface /
- nodal well-formedness /
- genetic algorithm
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