为了分析网壳结构的鲁棒性,基于H∞鲁棒控制理论,采用系统传递函数的H∞范数为结构鲁棒性定量评价指标,通过参数分析,研究几何参数、网格形式对单层网壳结构鲁棒性的影响.针对常见的凯威特型单层网壳结构,通过概念移除构件,分析构件的重要性,进而搜索影响鲁棒性的关键路径.针对某工程实例,讨论不同的支承形式对鲁棒性的影响.结果表明,结构跨度越小、构件截面和矢跨比越大,网壳结构的鲁棒性越强;相比肋环型和肋环斜杆型,凯威特型网壳结构鲁棒性较强;对于周边固支的凯威特型网壳结构,位于圆周直径上的径向构件对鲁棒性最重要;减少支座将降低结构的鲁棒性.
In order to investigate the robustness of reticular shells, the robustness was quantitatively assessed by H∞ norm of system transfer function, based on H∞ robust control theory. Through parametric analysis, influences of geometric parameters and grid configurations on the robustness of single-layer reticular shells were analyzed. For the common Kiewitt shells, components importance indices were calculated by component removal method. Furthermore the critical path for robustness was obtained. Taking an engineering practice for example, the impact of different forms of supports to robustness was discussed. The results showed that robustness of a reticular shell is stronger when the span is smaller, or the rise-span ra- tio and member sections are larger. Robustness of Kiewitt shells is better than Schwedler shells. For periphery fixed Kiewitt shells, the radial components located on the shell's diameters are the most important. Meanwhile, structural robustness would be decreased when reducing supports.