叶继红, 陆明飞. 单层空间网格结构刚性节点优化设计方法研究[J]. 工程力学, 2020, 37(2): 81-89,144. DOI: 10.6052/j.issn.1000-4750.2019.01.0092
引用本文: 叶继红, 陆明飞. 单层空间网格结构刚性节点优化设计方法研究[J]. 工程力学, 2020, 37(2): 81-89,144. DOI: 10.6052/j.issn.1000-4750.2019.01.0092
YE Ji-hong, LU Ming-fei. DESIGN OPTIMIZATION METHOD OF RIGID NODES IN SINGLE-LAYER GRIDSHELLS[J]. Engineering Mechanics, 2020, 37(2): 81-89,144. DOI: 10.6052/j.issn.1000-4750.2019.01.0092
Citation: YE Ji-hong, LU Ming-fei. DESIGN OPTIMIZATION METHOD OF RIGID NODES IN SINGLE-LAYER GRIDSHELLS[J]. Engineering Mechanics, 2020, 37(2): 81-89,144. DOI: 10.6052/j.issn.1000-4750.2019.01.0092

单层空间网格结构刚性节点优化设计方法研究

DESIGN OPTIMIZATION METHOD OF RIGID NODES IN SINGLE-LAYER GRIDSHELLS

  • 摘要: 单层网格结构中的节点不仅须传递轴力,也须传递两个方向上的弯矩。因此,单层网格结构中的节点为受力复杂的刚性节点,应具有合理的结构形式和良好的力学性能。同时,单层网格结构节点连接复杂、高空施工难度大,节点与杆件应有可靠、方便、通用的连接方式。该文提出了单层网格结构刚性节点优化设计方法:通过构造设计节点端,实现节点与杆件的连接;通过对受力复杂的节点核进行拓扑优化,开发高效的受力节点形式。在优化模型中,通过与外荷载无关的自平衡力系表示节点弯曲刚度,使得优化后的节点在任意方向上均有良好的弯矩传递能力。为避免拓扑优化中将力直接施加在设计域而导致的应力奇异问题及节点形式受限的缺点,通过施加加速度场,以体积惯性力等效集中荷载,降低了优化结果对边界条件的敏感性,获得了稳定、可靠的优化结果,解决了刚性节点拓扑优化中的关键技术难点。并以一个实际结构中的节点为例进行优化设计。通过分析节点端连接性能、力学性能以及与传统节点进行对比,验证了将拓扑优化和构造设计相结合的刚性节点优化设计方法。

     

    Abstract: The nodes in single-layer gridshells transmit axial forces and moments along two axes simultaneously. Therefore, the nodes in single-layer gridshells, which bear a complex combination of forces and moments, should have reasonable configurations and excellent mechanical performances as rigid connections. Moreover, because of the difficulty of assembling of the gridshell high above the ground and the complexity of the gridshell's configuration, the connections between nodes and members should be reliable, convenient and applicable to any situation. This paper proposes a design optimization method of rigid nodes in single-layer gridshells. The end piece of the node is firstly configured so that a bar can be connected to the node easily. Subsequently, topology optimization is carried out upon the node core to explore highly-efficient configurations. In the optimization model, the rotational stiffness of the node is represented by a set of self-equilibrium moments which are irrelevant to loads, and thus the optimal nodes can transmit moments from any direction. Applying the force directly upon the design domain will cause some problems, such as the stress singularity and limitations for the topology optimization to explore other potential configurations. To solve this key problem, an inertia action, which is generated by applying an acceleration field, is applied to be equivalent to the concentrated force. With this equivalence, reliable and stable optimal results are obtained which are insensitive to the boundary conditions. Finally, a real-life node is designed and optimized as an example. The analysis of the connection of the optimal node to tube members and the analysis of mechanical performances of the optimal nodes are conducted. And the optimal node is compared with the traditional node. The analyses and comparison verify the proposed design optimization method, which combines the design of connection and topology optimization.

     

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