大跨屋盖脉动风荷载谱模型研究

发布时间：2018-09-09 15:00

【摘要】：大跨度屋盖结构质量轻，柔度大，对风荷载作用较为敏感。屋盖形式多样，屋盖表面的脉动风荷载受特征湍流作用明显，拟定常假定不再适用。结合特征湍流的风荷载特性研究是风工程的热门研究方向，风荷载的确定也是大跨屋盖结构抗风设计的关键问题之一。风荷载谱是描述结构脉动风荷载的重要参数，也是结构抗风设计的必要依据。鉴于大跨屋盖结构复杂的空气动力特性与结构动力特性，目前风荷载谱模型一般根据风荷载测量结果拟合得到，尚无统一的拟合形式，且模型参数的物理意义不明确，得到的拟合参数结果离散性大，因此参数值对结构动力响应的影响难于估量。为此，有必要对风荷载谱的建模理论进行完善，提出一种普适性较强且便于应用的风荷载谱模型。本文在回顾大气湍流风速谱模型以及各学者针对低矮房屋及高层建筑风荷载谱模型的基础上，提出了一种新的风荷载谱模型，通过理论推导及统计分析，建立了该模型中参数与谱曲线形状、特征湍流作用及结构风振响应间的关系，探讨了参数的数学意义、物理意义及力学意义。并结合风洞试验数据，建立了典型大跨屋盖结构的风荷载谱模型。主要包含以下几方面内容： 1、借鉴大气湍流风速谱的建模思路，对一种常用的风荷载谱模型拟合公式中的参数进行数学变换，得到一种由三个自功率谱参数表达的风荷载自功率谱模型，，对于互功率谱模型仍采用由模型衰减指数表达的指数型相干函数模型。 2、基于随机振动理论探讨了模型中四个参数对结构动力响应的影响，建立了风荷载谱模型参数与结构风振响应的联系。 3、基于115组工况的典型大跨屋盖（包括平屋盖、悬挑屋盖、柱面及球面屋盖）风洞试验数据，获得风荷载谱模型参数，并统计分析了不同流场条件、不同形式屋盖上谱参数的取值范围与分布规律，探讨了参数与特征湍流作用间的联系，证实谱模型具有一定的物理内涵。 4、基于不同屋盖特征湍流作用形式，结合参数对结构响应的敏感性分析，对上述所有风洞试验工况谱参数进行统计，整理出更具普适意义的大跨屋盖结构风荷载谱模型，并通过642个结构风振响应分析算例（包括平板网架、悬挑桁架、双层柱面网壳、单层球面网壳）验证了模型的有效性和建模方法的适用性。最后，结合随机模拟、数据挖掘与数据库技术探讨了本文提出的风荷载谱建模方法在极值风荷载估计、风荷载特性分析、风荷载预测及结构抗风设计中的应用前景。
[Abstract]:The large span roof structure is light in weight, flexible and sensitive to wind load. Because of the variety of roof forms, the fluctuating wind load on the roof surface is obviously affected by the characteristic turbulence, so it is often assumed that it is no longer applicable. The study of wind load characteristics combined with characteristic turbulence is a hot research direction in wind engineering, and the determination of wind load is also one of the key problems in wind resistant design of long-span roof structures. Wind load spectrum is an important parameter to describe the fluctuating wind load of structures, and it is also a necessary basis for the design of wind resistance of structures. In view of the complex aerodynamic characteristics and structural dynamic characteristics of long-span roof structures, the current wind load spectrum model is generally fitted according to the results of wind load measurement, and there is no uniform fitting form, and the physical meaning of the model parameters is not clear. The results of fitting parameters are discrete, so the influence of parameters on the dynamic response of structures is difficult to estimate. Therefore, it is necessary to perfect the modeling theory of wind load spectrum, and put forward a kind of wind load spectrum model, which has strong universality and is easy to be applied. On the basis of reviewing the wind speed spectrum model of atmospheric turbulence and the wind load spectrum model of low-rise buildings and high-rise buildings, a new wind load spectrum model is proposed in this paper, which is derived theoretically and analyzed statistically. The relationship between the parameters and the shape of the spectral curve, the characteristic turbulence and the wind-induced vibration response of the structure is established, and the mathematical, physical and mechanical meanings of the parameters are discussed. Combined with wind tunnel test data, the wind load spectrum model of typical long span roof structure is established. The main contents are as follows: 1. The parameters of a commonly used wind load spectrum model fitting formula are transformed by mathematical method for reference to the modeling idea of atmospheric turbulence wind speed spectrum. A wind load self-power spectrum model, which is expressed by three parameters of self-power spectrum, is obtained. For the cross-power spectrum model, the exponential coherent function model expressed by the attenuation exponent of the model is still used. 2. Based on the random vibration theory, the influence of the four parameters on the dynamic response of the structure is discussed. The relationship between the wind load spectrum model parameters and the wind-induced vibration response of the structure is established. 3. Based on the wind tunnel test data of 115 sets of typical long-span roof (including flat roof, cantilever roof, cylindrical roof and spherical roof), The parameters of the wind load spectrum model are obtained, and the range and distribution of spectral parameters in different flow field conditions and different forms of roof are analyzed, and the relationship between the parameters and the characteristic turbulence is discussed. It is proved that the spectral model has certain physical connotations. 4. Based on the different roof characteristic turbulence forms and the sensitivity analysis of the parameters to the structural response, the spectral parameters of all the above wind tunnel test conditions are statistically analyzed. A more universal wind load spectrum model of long-span roof structure is presented, and the wind vibration response of 642 structures (including plate grid, cantilever truss, double-layer cylindrical latticed shell) is analyzed. The validity of the model and the applicability of the modeling method are verified. Finally, combined with stochastic simulation, data mining and database technology, the application prospect of wind load spectrum modeling method proposed in this paper in extreme wind load estimation, wind load characteristic analysis, wind load prediction and wind resistant design of structures is discussed.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU312.1

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