柔性結構非接觸變形量測與風壓反算; Non-Contact Measurement of the Displacement of Flexible Structure and the Back Calculation of the Surface Wind Pressure

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Title:	柔性結構非接觸變形量測與風壓反算;Non-Contact Measurement of the Displacement of Flexible Structure and the Back Calculation of the Surface Wind Pressure
Authors:	陳思翰;Chen,Szu-Han
Contributors:	土木工程學系
Keywords:	風洞實驗;風速壓;柔性結構;非接觸式影像量測;順風向反應;結構動態分析
Date:	2013-08-15
Issue Date:	2013-10-08 09:28:53 (UTC+8)
Publisher:	國立中央大學
Abstract:	近年在營建技術的發展下，高層建築使用質量輕、強度高的建築材料，致使結構對風所引發之振動效應特別敏感，使得高樓建築在設計時常考慮風力作用而進行風洞實驗，針對結構物所受風力、風壓與舒適性評估進行研究。本文係針對柔性結構於兩種不同流況中之風洞實驗進行結構變形量測，實驗量測主要利用一套非接觸式的影像量測技術，透過攝影機拍攝覘標點位，量測試體受風力拖曳產生之動態撓度歷時反應，並以試體迎風面與背風面之應變計量測應變歷時反應；分析模式則運用梁理論與風速壓預測結構受風力作用的平均撓度與應變反應，並與實驗量測結果相互比對，顯示不論低紊流或高紊流風場中，透過風速剖面參數預測結構變形軌跡均能有不錯的結果；於第五章利用白努利-尤拉梁之振動方程式，透過線性獨立的特性假設撓度與外力函數型式，更進一步推導出結構的動態行為與風壓反算之簡易方法，而與實驗量測結果比對亦相當吻合，其可作為實際結構動力反應之依據，或可提供模擬程式開發用以驗證模式準確性之資料庫數據使用。 Due to the construction technology development in recent years, high-rise buildings use light weight and high strength materials which causes the structure to be particularly sensitive to the wind-induced vibration effects. Therefore, it is necessary to often conduct wind tunnel experiments to evaluate the wind effect on the design of high-rise building. In this thesis, the dynamic deflection responses of a flexible structure under wind actions in two different flow conditions of wind tunnel experiment were measured through a non-contact imaging analysis. The dynamic strain data were measured by strain gauges deployed at various sections at the same time. The beam theory and assumed wind pressure pattern were used to predict the average deflection and strain responses of the structure by wind action and then were compared with experimental measurements. The results show that both the predicted structural responses under the low or high turbulent wind fields will match the measured structural deformation trajectory. Besides, dynamic Bernoulli-Euler beam equation and the strain data were used to back calculate the coefficients of the assumed pressure function. The predicted deflection responses compared with experimental measurements are very consistent. This result can be used as the basis for the actual structural dynamic analysis for wind engineering. The experimental results can also be provided to verify the accuracy of wind-structure analysis software.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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