索膜接触对气承式膜结构风致响应的影响

Influence of cable-membrane contact on wind-induced responses of air-supported membrane structures

目前对于索网加劲气承式膜结构的设计,通常将模型简化为索网与膜面直接连接,而忽略索网与膜面之间的摩擦滑移,这种简化处理方法对大跨度气承式膜结构的设计安全造成很大的隐患。为此,利用ANSYS软件,将气承式膜结构索膜之间的摩擦滑移作为接触问题来考虑,建立接触模型,并对其进行初始形态分析和风荷载响应分析。结果表明:当不考虑索膜接触滑移的影响时,会高估索网对膜面的约束作用,计算的膜面位移偏小,索网轴力偏大,且容易出现应力集中的现象;考虑索膜接触滑移时,索网对膜面的约束能力明显下降,在风荷载作用下膜面的位移明显增加,迎风面处的膜面和索网甚至会发生分离。因此需要考虑索膜接触滑移才能正确进行气承式膜结构的风致响应分析,避免安全事故的发生。

At present, for the design of the cable-net-stiffened air-supported membrane structures, the model is usually simplified so that the cable-net and the membrane surface are directly connected, ignoring the friction and slip at the surface. This simplification has caused great hidden risks for the design safety of the membrane structures. Therefore, using the ANSYS software, the frictional slip between the cable and membrane of the air-supported membrane structure was considered as a contact problem. A contact model was established, and the initial shape analysis and the analysis on wind load-induced responses were carried out. The results show that when the influence of cable-membrane contact slip is not considered, the restraint effect of the cable net on the membrane surface will be overestimated, the calculated displacement of the membrane surface is too small, the axial force of the cable network is too large, and the phenomenon of stress concentration is prone to occur. When the cable-membrane contact slip is considered, the restraint ability of the cable-membrane to the membrane surface decreases significantly, the displacement of the membrane surface increases significantly under the action of wind load, and the membrane surface and the cable-membrane at the windward side even separate. Only by considering contact slip analysis, the wind-induced response analysis of the air-supported membrane structure can be carried out correctly to avoid the occurrence of safety accidents.