| 引用本文: | 余玮,柯世堂.大型冷却塔风致响应极值现场实测和有限元对比[J].哈尔滨工业大学学报,2018,50(6):23.DOI:10.11918/j.issn.0367-6234.201709108 |
| YU Wei,KE Shitang.A comparative study between field measurement and finite element analysis of wind response extreme of large cooling tower[J].Journal of Harbin Institute of Technology,2018,50(6):23.DOI:10.11918/j.issn.0367-6234.201709108 |
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| 摘要: |
| 通过现场实测数据分析发现冷却塔局部加速度响应呈现显著的非高斯分布，而基于高斯假定的风致响应极值估算方法已不能完全适用.为研究考虑非高斯特性的风致响应极值分布，以西北地区某179 m高大型冷却塔为研究对象，通过现场实测获取环境激励下塔筒典型部位的加速度振动信号，首先结合随机减量法和自然激励技术对信号进行预处理，再采用ARMA、ITD和STD三种模态识别方法获取了冷却塔前10阶自振频率和阻尼比，并与有限元动力特性结果进行对比验证，再借鉴振型组合思路提出结构等效综合阻尼比.采用两种极值估算方法(峰值因子法和Sadek-Simiu法)计算了不同样本的峰值因子和加速度响应极值，并给出了实测响应极值单一取值.最后基于完全瞬态时域法进行了实测阻尼比2%和规范阻尼比5%下的风振响应分析，并将有限元与实测响应极值进行对比和误差分析.实测和有限元分析对比研究表明:实测和有限元分析的结构前10阶自振频率结果较为一致，最大相差9%；两种极值估算方法获得的实测加速度响应极值最大相差32.02%；局部测点在实测阻尼比下的有限元风振响应极值与实测极值较为一致.
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| 关键词: 大型冷却塔 现场实测 模态识别 瞬态分析 极值响应 |
| DOI：10.11918/j.issn.0367-6234.201709108 |
| 分类号:TU279.7+41 |
| 文献标识码:A |
| 基金项目:国家自然科学基金(U9,4)； 江苏省优秀青年基金(BK20160083)； 江苏省六大人才高峰高层次人才计划(JZ-026) |
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| A comparative study between field measurement and finite element analysis of wind response extreme of large cooling tower |
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YU Wei,KE Shitang
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(Department of Civil Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China)
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| Abstract: |
| A remarkable non-Gaussian distribution of local acceleration responses of the cooling tower is indicated through field measured data analysis, and extreme estimation method based on Gaussian assumption of wind-induced responses are not fully applicable. To study the extreme considering non-Gaussian characteristics, a 179 m high large cooling tower in northwest was selected, and acceleration vibration signals at representative positions of the tower were obtained under ambient excitation. The vibration signals were preprocessed combining random decrement technique and natural excitation technique. Three pattern recognition methods (ARMA, ITD and STD) were applied to analyze the frequencies and damping ratios for the first ten order modes, and comparison between measured values and the finite element calculation were carried out. Following modal combination, equivalent synthetic damping ratio of the cooling tower was derived. The peak factors and acceleration response extreme of samples were calculated by two kinds of extreme estimation methods (peak factor method and Sadek-Simiu method), and a single value of the measured response was given. The wind-induced response analysis was carried out under the measured damping ratio 2% and the standard damping ratio 5% based on the total transient time domain method, and error analysis between measured values and the finite element calculation was carried out. The comparative study shows that the results of the measured and finite element analysis are consistent with the results of the first 10 frequencies, with the maximum difference of 9%. The maximum difference between the measured acceleration responses of the two extreme estimation methods is 32.02%, and local points of wind vibration response extreme of finite element under measured damping ratio and the measured extreme are consistent.
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| Key words: large cooling tower filed measurement modal identification transient analysis extreme responses |
