Development of wind-resistant suspended membrane roof for rainproof dam construction

用于防雨大坝建设的悬膜屋顶由一层膜组成，该膜由两根跨在两岸之间的平行电缆支撑。这种屋顶的优势在于它可以根据施工阶段进行定位，并且不会妨碍施工过程。然而，由于其结构极其轻且灵活，在风速约为20 m/s时，会出现发散现象。即使在较低的风速下，当风吹起时，散度也会发生。本研究的目的是开发能承受大风的悬吊膜屋盖系统。对于抗风膜屋盖的发展，了解发散的发生机理是至关重要的。因此，我们试图建立一种分析方法，使膜运动和风力耦合现象可以用二维计算流体力学来求解。由于风的作用改变了膜的形状，从而导致了不同的风力，这一现象比较复杂，因此对膜的大振幅动力运动与风力耦合的分析还没有得到稳定的计算结果。然后对影响膜稳定性的散度的静响应进行了分析。仔细考虑了膜运动与风力的耦合过程，建立了膜的平衡形状随风力变化的解析过程。所得结果与以往的实验结果定性一致。

The suspended membrane roof for rainproof dam construction consists of a membrane that is supported by two parallel cables spanned between the banks. This roof is advantageous because it can be located according to the construction stage and it will not prevent the construction procedure. However, the divergence phenomenon is observed under wind speed of about 20 m/s due to its extremely light and flexible structure. Divergence occurs even under lower wind speed when the wind blows up. The objective of this study is to develop the suspended membrane roof system that withstands even the blow up wind.For the development of the wind-resistant membrane roof, it is essential to understand the divergence occurrence mechanism. Therefore we tried to develop an analytical procedure so that the coupled phenomenon of membrane motion and the wind forces can be solved using 2 dimensional computational fluid dynamics. Because the phenomenon is complicated where the wind force changes the membrane shape that results in the different wind forces, the analysis that couples large amplitude dynamical membrane motion and wind forces have not produced stable computational results yet. Then the static response that affects divergence which is dominant for the membrane stability is tried to be analyzed. By carefully considering the procedure how to couple the membrane motion and the wind forces, we developed the analytical procedure with which the equilibrium membrane shape with the wind force can be obtained. The obtained results qualitatively agreed with the previous experimental results.