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利用HHT方法对非平稳风力的时频分析 被引量:7
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作者 赵杨 武岳 +3 位作者 曹曙阳 段忠东 yukio tamura S. Ozono 《振动与冲击》 EI CSCD 北大核心 2011年第2期5-9,14,共6页
非平稳信号的分析方法是信号分析领域中的一个重要问题。以风洞试验获得的非平稳风压信号和升力系数信号为研究对象,采用HHT方法对信号进行时频分析。HHT(Hilbert-Huang transform)方法可以获得有意义的瞬时频率,从而给出频率随时间变... 非平稳信号的分析方法是信号分析领域中的一个重要问题。以风洞试验获得的非平稳风压信号和升力系数信号为研究对象,采用HHT方法对信号进行时频分析。HHT(Hilbert-Huang transform)方法可以获得有意义的瞬时频率,从而给出频率随时间变化的精确表达;信号最终被表示为时频平面上的能量分布,成为Hilbert谱;该方法适用于分析生活中普遍存在的大量频率随时间变化的非线性、非平稳信号,可将复杂的信号直接分离成从高频到低频的若干阶固有模态函数。分析结果虽然没有表现出明显的频谱分布特性,但与以往HHT分析结果提取的固有模态函数不同,如果对该试验获得的非平稳信号提取的固有模态是低频部分的残余信号,忽略其他高频信号,则风压时程和升力系数时程的残余信号曲线就可以分别回归为一个线性函数和一个正弦函数。这也说明,该非平稳信号的主成分仍然是由平稳信号组成的,可以用分析平稳信号的方法进行时程分析。 展开更多
关键词 非平稳信号 希尔伯特-黄 经验模态分解法 固有模态函数 时程分析
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多国荷载规范中阵风荷载因子的比较研究 被引量:8
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作者 赵杨 段忠东 +1 位作者 yukio tamura 武岳 《哈尔滨工程大学学报》 EI CAS CSCD 北大核心 2010年第11期1465-1471,共7页
将我国的《建筑结构荷载规范》(GB5009-2001)与美国(ASCE7-98)、日本(RLB-AIJ2004)、加拿大(NBC1990)和澳大利亚(AS1170.2)几国规范进行了比较研究.首先总结了各国规范所采用的Davenport提出的经典抗风设计方法——阵风荷载因子法(GLF)... 将我国的《建筑结构荷载规范》(GB5009-2001)与美国(ASCE7-98)、日本(RLB-AIJ2004)、加拿大(NBC1990)和澳大利亚(AS1170.2)几国规范进行了比较研究.首先总结了各国规范所采用的Davenport提出的经典抗风设计方法——阵风荷载因子法(GLF),然后对包括平均风速剖面、湍流强度、脉动风速谱类型进行了比较.美日加澳都将GLF取为一个恒量,相当于"位移风振系数",中国规范中的风振系数却是随高度变化的量,相当于"惯性力风振系数". 展开更多
关键词 阵风荷载因子法 随机振动理论 风速谱 湍流强度 平均风剖面
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雷暴冲击风模拟及其荷载的风洞试验研究 被引量:25
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作者 赵杨 曹曙阳 +2 位作者 yukio tamura 段忠东 S. Ozono 《振动与冲击》 EI CSCD 北大核心 2009年第4期1-3,9,共4页
为了研究在突变气流作用下结构的空气动力特性,介绍了利用主动控制风洞模拟突变气流的试验研究。首先通过该风洞模拟出了雷暴冲击风阵风剖面;然后,采用"阶跃流法"模拟了风速突变的时程;最后将高层结构模型置于该突变气流中,... 为了研究在突变气流作用下结构的空气动力特性,介绍了利用主动控制风洞模拟突变气流的试验研究。首先通过该风洞模拟出了雷暴冲击风阵风剖面;然后,采用"阶跃流法"模拟了风速突变的时程;最后将高层结构模型置于该突变气流中,观测在特殊气流中结构表面风压以及结构空气动力学参数的变化特征。试验结果表明,利用主动控制风洞模拟出的雷暴冲击风阵风剖面同理论的相似性达到90%以上,突变气流会使高层结构整体产生较大的非定常升力,并且在结构表面产生较大的非定常风压。 展开更多
关键词 雷暴冲击风 阶跃流法 主动控制风洞 风洞试验
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Shape Optimization and Assessment of Wind Induced Stresses in Domes
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作者 K. S. Babu Narayan Subhash C. Yaragal yukio tamura 《Journal of Civil Engineering and Architecture》 2012年第7期925-927,共3页
Domes are popularly used for column free areas. They are employed as covers to reservoirs and treatment units and also as containment in nuclear reactors. Inverted domes are popular as foundations. Structures are buil... Domes are popularly used for column free areas. They are employed as covers to reservoirs and treatment units and also as containment in nuclear reactors. Inverted domes are popular as foundations. Structures are built with an intended end use for a specified utility period. The functional requirement is to serve the purpose and the structural requirement constitutes stability, strength, safety, serviceability and durability. Satisfaction of these requirements at affordable costs is the goal of structural optimization. This paper demonstrates the need and scope for optimization of domes by formulating and solving the problem by use of calculus (volume of material is the objective function being minimized using first principles of calculus). A simple but elegant method is suggested for determination of wind stresses by statics which compares very well with that obtained by rigorous method. 展开更多
关键词 DOME SHAPE wind stresses SEARCH optimization.
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A prototype online database-enabled design framework for wind analysis/design of low-rise buildings 被引量:1
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作者 Dae Kun KWON Ahsan KAREEM +1 位作者 Deepak KUMAR yukio tamura 《Frontiers of Structural and Civil Engineering》 CSCD 2016年第1期121-130,共10页
This study presents a development of an advanced cyberbased database-enabled design module for low- rise buildings (DEDM-LR) which provides estimation of the wind-induced responses for main wind force resisting fram... This study presents a development of an advanced cyberbased database-enabled design module for low- rise buildings (DEDM-LR) which provides estimation of the wind-induced responses for main wind force resisting frames by making direct use of pressure time histories measured at a large number of pressure taps over a suite of building models. These responses may be considered in lieu of code-specified load effects in which the overall accuracy may be influenced by the inherent simplifications in codes. In addition, this new automated approach is particularly attractive and advantageous as it allows a web-based online analysis/design via intuitive user-friendly interfaces for both the input and output in terms of familiar web-style forms that are nowadays very common in most of web-based services. Presently, the DEDM-LR hosts an aerodynamic database developed by the Tokyo Polytechnic University (TPU), Japan for a variety of building configurations like flat, gable, and hip roofs under suburban terrain flow condition with immediate application to other databases. The paper shows the efficacy and validity of the DEDM-LR by walking through its details and examples on selected gable-roofed buildings. The architecture of DEDM-LR platform offers the ability to pool resources by hosting other databases that may become available in the near future. 展开更多
关键词 wind loads low-rise building pressure measurement AERODYNAMICS building design structural response building codes information technology (IT)
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