動力互易定理於樑損傷檢測之應用; Damage Detection in Beam Structures Using Dynamic Reciprocal Theory

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Title:	動力互易定理於樑損傷檢測之應用;Damage Detection in Beam Structures Using Dynamic Reciprocal Theory
Authors:	連祥益;Hsiang-Yi Lien
Contributors:	土木工程研究所
Keywords:	樑;裂縫;互易定理;傳遞函數;振態;動態量測;快速傅立葉轉換;頻譜;beam;crack;reciprocal theory;transfer functi
Date:	2001-07-09
Issue Date:	2009-09-18 17:08:37 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	結構物損傷可能導致重大的災難產生。因此，近十年來，諸多學者專注偵測結構物損傷存在及位置方法的研究。一般而言，最理想的結構物損傷檢測方法是可使用最少量測儀器及最短施測時間。由此論點，本論文引用Graffi線彈性動力互易定理及動態量測之觀念，發展樑損傷之檢測方法。透過此互易定理，可僅使用一個感測計結合移動式敲擊力，經由敲擊力與感測計互易關係獲得相當於在感測計位置施加脈沖函數作用力時，在敲擊位置之結構反應。藉由量測感測計及敲擊力的歷時反應可以獲得沿著樑在敲擊點之柔度、可動性及慣性傳遞函數。再由傳統的振態分析技巧配合樑的頻譜圖，可繪得傳遞函數之空間振態。透過此研究，重疊放置不同位置的感測計所獲得樑的傳遞函數第三振態，可以偵測裂縫位置。目前，僅對單一裂縫樑作深入探討。未來仍需要對此方法的正確性及發展於實地檢測上作深入研究。 The existence of damage may cause catastrophic failure of structure. Hence, methods of Damage detection and localization in structure has been drawn much attention by researchers for decades. The most attractive method of structure damage detection is the one using the least number of sensors and requiring minimum conducting time. In this thesis, a dynamic inspection method for damage detection of beam is developed based on the Graffi reciprocal theory in elastodynamics. Through this reciprocal theory, it is possible to use only one sensor combining with moving impact force to obtain the dynamic responses of the system at sites where impact force applied under a delta load exciting at the location where sensor is located. Transfer functions of compliance, mobility and inertia at points along the beam can be obtained from the measured response and impact force history. The spatial mode shape of transfer function at various frequency of the beam can be obtained by the conventional modal analysis techniques. Through the study, it is interested to find that the location of a crack in the test beam can be detected by the intersection of the third mode shape functions generated from data of different sensors on the test beam. At present time, only beam with a single crack was studied in detail. Further research is required to prove the accuracy of this newly proposed method and reveal the truth behind the interesting finding that currently achieved.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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