【作者】 杨毅；

【导师】 楼文娟；

【作者基本信息】 浙江大学 ， 结构工程， 2004， 硕士

【摘要】 风对建筑物特别是大跨度柔性屋面结构的影响愈来愈受到人们的重视，大跨度柔性屋盖结构的风振系数和风振响应的研究有待深入，尤其是对建筑物突然开孔状态下柔性屋面的风振响应研究尚处于初步阶段，大跨结构气动阻尼在结构风振响应中起重要作用，但至今缺乏研究。本文针对屋盖结构的风振响应问题，在以下三个方面做了探讨研究： 第一，屋盖的风振响应模态分析。本文提出了利用刚性模型风洞试验确定大跨度屋盖风振响应和风振系数的多阶模态力法，并且与直接时程分析法以及气动弹性模型风洞试验结果进行了对比，表明多阶模态力法准确、便捷。并发现对于某些大跨度非平板式屋盖结构，由于其低阶振频较为密集，高阶振型对风振响应和风振系数的影响不可忽略。 第二，突然开孔内压响应理论分析。建筑物突然开孔状态下内压响应的理论在国内缺乏研究，本文对国外在这方面的研究成果做了总结，采用考虑建筑物柔度的内压传播方程，计算了脉动风作用下建筑物突然开孔所产生的内压瞬态响应，并对内外压传递方程参数取值做了进一步的探讨，同时分析了开孔率，建筑物容积，结构刚度，气弹刚度同脉动内压的关系，得到了一些有意义的结论，为今后进一步的研究打下基础 第三，建筑物突然开孔状态下气动阻尼的确定。判定结构阻尼的方法很多，各有其优缺点，而经验模态分解方法被认为是目前提取数据序列趋势或均值的最好方法，并且能够客观地处理非线性问题。本文联合采用经验模态分解法、随机减量法和希耳伯特变换法，结合气动弹性模型试验结果，分析研究了大跨度柔性屋面在四周封闭和突然开孔两种情况下的气动阻尼随风速的变化规律，发现在突然开孔状态下气动阻尼变化很大，其对屋面响应的影响不可忽略。更多还原

【Abstract】 Wind effects on buildings especially on long-span flexible roofs became more and more important. The investigation on dynamic response and wind load factor of long-span flexible roof is not sufficient. Especially, the researches on dynamic response of roofs in the case of sudden opening are still in preliminary stage. Aerodynamic damping of long-span structure plays an important role in wind response of structures. This paper focuses on wind response and aerodynamic damping of long-span roof structures, and the main work is as following.1. Modal analysis on dynamic response of long-span roof structures. This paper brings forward the multi-modal force method using the result of rigid model wind tunnel test to determine wind-induced dynamic response and wind load factor of long-span roof structures. Compare with the results from the time domain method and aeroelastic model wind runnel test, it is shown that the results predicted by the present method have high precision. And in the present method, the contributions of higher vibration modes can be taken into account.2. Theoretical analysis of internal pressure on buildings in the case of sudden opening. Study on the internal pressure dynamics is not widely carried out in our country. This paper gives a summary of alien research results so far. Dynamic wind velocity on opening is simulated using Davenport spectrum and then the transient internal pressure response is computed by adopting a governing differential equation considering the flexibility of roof structure. The relationship of internal pressure to the size of opening, the bulk of building, the structural flexibility and aeroelastic stiffness are also studied. Finally, some significant conclusions are obtained.3. Determination of aerodynamic damping of buildings on conditions of sudden opening. Various methods for determination of aerodynamic damping are available, nevertheless the empirical mode decomposition (EMD) method is thought to be the most suitable method to extract data array trends or mean value, which can treat nonlinear problems objectively. Combined the EMD method, the random decrement technique (RDT) and the Hilbert transform (HT), the aerodynamic damping ratios of long-span flexible roof in the case of round close situation and sudden opening situation are calculated respectively. It is shown that the affect of aerodynamic damping to roof can’t be ignored in the sudden opening case.更多还原