大跨度桥梁空间脉动风场的数值模拟  

Numerical Simulation of Spatial Fluctuating Wind Field on Long-Span Bridges

作　　者：包龙生[1] 刘克同[1] 于玲[1] 牛宏[2] 

机构地区：[1]沈阳建筑大学土木工程学院,辽宁沈阳110168 [2]中交第一公路勘察设计研究院有限公司,陕西西安710075

出　　处：《沈阳建筑大学学报（自然科学版）》2010年第2期238-243,共6页Journal of Shenyang Jianzhu University：Natural Science

基　　金：辽宁省教育厅科技攻关项目(2008586);中国交通建设集团科技研发项目(kyht2008-05)

摘　　要：目的传统谐波合成法(WAWS法)计算量大、内存耗费多,为解决这一问题探讨一种高效又不失精度的脉动风场模拟方法.方法采用BP神经网络来拟合分解谱密度函数曲线,以减少互谱密度谱的Cholesky分解次数;同时运用离散快速FFT技术来减少谐波项合成所需要的时间,并结合桥梁自身的结构形式及风致响应特点,考虑脉动风场的有关特性,得到一种简化的三维脉动风速场模拟方法.分别采用现有的WAWS法和改进的WAWS法对一结构模型选取多点进行空间多个相关脉动风速的模拟.结果现有的WAWS法占用内存35.7MB,耗时134.9min;改进的WAWS法占用内存4.1MB,耗时间193s.改进的WAWS法计算效率明显提高.结论改进的WAWS法可以高效、准确地模拟出适合大跨度桥梁结构的随机脉动风场.In order to reduce the calculating amount and memory consumption of the traditional wave superposition method and to obtain a highly effective simulation method not losing the precision, BP neural network interpolation method is utilized to fit the factorized spectrum function curves, which can reduce the calculating amount of Cholesky factorizations. Furthermore, the FFT technique is used to decrease the time consumption of the wave superposition. According to the features of structural style and vibration mode of longspan bridge,considering the correlation of the fluctuating wind, a simulated method for simplified three-di- mensional fluctuating wind field is presented. A structure model was chosen to carry on the simulation of correlated multi-point in the space, respectively, by using WAWS method and improved WAWS method. Memory for the WAWS method is 35. 7 MB and time-consuming 134. 9 rain;Memory for improved WAWS method is 4. 1 MB and time-consuming 193 s. The improved WAWS method remarkably promotes the computational efficiency. The example using these methods is employed to indicate that the fast simulation method is suitable for simulating the stochastic wind field of long-span bridge structures effectively and accurately.

关 键 词：谐波合成法 CHOLESKY分解 大跨度桥梁 脉动风场 

分 类 号：TU416.214[建筑科学—岩土工程]