刚性模型风洞试验确定大跨屋盖结构风振系数的多阶模态力法

Determination of wind load factors of long-span roof structures using rigid model wind tunnel test

风流经过大跨屋面时,由于气流分离在屋面的大部分区域产生强大的吸力,并引起柔性屋面结构的振动,因此大跨屋面结构抗风设计需考虑风振响应和风振系数。本文根据振型迭加原理,提出了利用刚性模型风洞试验确定大跨度柔性屋盖结构风振响应和风振系数的多阶模态力法,并推导了风振响应和风振系数的计算公式。该方法可以考虑高阶振型的贡献。通过与气动弹性模型风洞试验结果以及直接时程法相对比,发现多阶模态力法能够得出令人满意的结果。

The wind load has recently become a major concern in wind-resistant design of long-span roof structures due to their characteristics: light, flexible, lightly damped, low natural frequency and so on. Flexible roofs will suffer from wind-induced dynamic response under high suction fluctuating pressure when wind flows over the long-span roof structures. Wind load factor is the essential parameter in wind resistance design of long-span structures in order to consider wind dynamic effects. A multi-modal force method combined with rigid model wind tunnel test is provided to estimate the wind load factor of long-span flexible roofs. In the present method, the contributions of higher vibration modes can be taken into account. Comparing with the results from the perfect aeroelastic model wind tunnel tests and the time domain method, it is found that the results predicted by the present method have high precision.