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完整後設資料紀錄
DC 欄位 | 值 | 語言 |
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dc.contributor.advisor | 劉佩玲(Pei-Ling Liu) | |
dc.contributor.author | Cheng-Yu Yeh | en |
dc.contributor.author | 葉承瑜 | zh_TW |
dc.date.accessioned | 2021-06-15T16:16:45Z | - |
dc.date.available | 2018-08-28 | |
dc.date.copyright | 2015-08-28 | |
dc.date.issued | 2015 | |
dc.date.submitted | 2015-08-17 | |
dc.identifier.citation | [1] M. Sansalone and N. J. Carino, Impact-Echo:A Method for Flaw Detection in Concrete Using Transient Stress Waves. Gaithersburg, MD:National Bureau of Standard 1986.
[2] C. Cheng and M. Sansalone, 'The Impact-Echo Response of Concrete Plates Containing Delaminations: Numerical, Experimental and Field Studies,' Material and Structures, vol. 26, pp. 274-285, 1993. [3] Y. Lin and M. Sansalone, 'Transient Response of Thick Circular and Square Bars Subjected to Transverse Elastic Impact,' J. Acoustical Society of America, vol. 91, pp. 885-893, 1992. [4] Y. Lin and M. Sansalone, 'Transient response of thick rectangular bars subjected to transverse elastic impact,' J. Acoustical Society of America, vol. 91, pp. 2674-2685, 1992. [5] C. Cheng and M. Sansalone, 'Effects on Impact-Echo Signals Caused by Steel Reinforcing Bars and Voids around Bars,' ACI Materials Journal, vol. 90, pp. 421-434, 1993. [6] P. L. Liu and C. Y. Yiu, 'Imaging Of Concrete Defects Using Elastic Wave Tests,' presented at the the 2002 Far-East Conference on Nondestructive Testing, Tokyo, Japan, 2002. [7] 葉柏涼, '敲擊回音法之時間-頻率域分析與影像法,' 應用力學研究所, 臺灣大學, 2006. [8] Y. Xiang and S. K. Tso, 'Detection and classification of flaws in concrete structure using bispectra and neural networks,' NDT & E International, vol. 35, pp. 19-27, 2002. [9] 郭建成, '經驗模態分解應用於敲擊回音法之鋼筋與裂縫辨識,' 應用力學研究所, 臺灣大學, 2007. [10] 許嘉文, '敲擊回音法於傾斜裂縫影像修正之探討,' 應用力學研究所, 臺灣大學, 2012. [11] 柯智雄, '雙譜應用於敲擊回音法之鋼筋與裂縫辨識,' 應用力學研究所, 臺灣大學, 2012. [12] 林力權, '敲擊回音相位於鋼筋與裂縫檢測應用,' 應用力學研究所, 台灣大學, 2014. [13] F. Leonard, 'Phase spectrogram and frequency spectrogram as new diagnostic tools,' Mechanical Systems and Signal Processing, vol. 21, pp. 125-137, 2007. [14] Y. Lin, Sansalone M. & Carino N. J., 'Finite Element Studies of the Transient Response of Plates Containing Thin Layers and Voids,' J. Nondestructive Evaluation, vol. 9, pp. 27-47, 1990. [15] J. O. Hallquist, LS-DYNA Keyword User's Manual. Livermore: Livermore Software Technology Corporation, 2003. | |
dc.identifier.uri | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/52504 | - |
dc.description.abstract | 敲擊回音法已廣泛的應用在混凝土內部缺陷的檢測,利用試體表面敲擊產生的應力波,將試體表面位移經由傅立葉轉換頻譜中的回音尖峰判讀缺陷位置。然而由回音尖峰無法顯示反射界面是鋼筋還是裂縫所造成。
本研究主要提出一個自動化判別混凝土內鋼筋及裂縫的方法,在敲擊回音試驗中,試體表面產生的壓力波遭遇自由界面會產生張力回波,遭遇固定界面則會產生壓力回波,故兩種不同界面所產生的敲擊回音相位不同。根據此原理,本研究逐以試體表面位移訊號之傅立葉相位頻譜發展鋼筋與裂縫訊號的判別方法。 本研究以有限元素分析內含8到12公分深裂縫及4到6公分深鋼筋的混凝土之敲回音反應,並對二塊混凝土試體進行模型試驗,各含有12公分深裂縫及6公分深的鋼筋。將模擬與模型訊號之相位頻譜中對應於回音頻率的相位及相位斜率畫在相位—相位斜率的圖上,可以明顯的看出裂縫與鋼筋分佈在兩個分隔的區域,裂縫相位較接近0,鋼筋相位較接近pi/2,且鋼筋相位斜率偏低。因此本研究便以回音相位及相位斜率作為判斷反射界面類別的特徵參數。 本研究利用線性及類神經網路兩種分類器對前述訊號進行分類。線性分類器是直接在相位—相位斜率圖上以一垂直線(一元區分法)及一斜線(二元區分法)將裂縫及鋼筋兩群資料分開,此二直線均可作為決策邊界,可擇一使用。當產生新的敲擊回音訊號時,可將其回音相位及相位斜率直接點在圖中,看此點落於決策邊界那一側來判斷反射界面的種類。 本研究之類神經網路分類器是以一個倒傳遞網路作為基礎,以回音相位及相位斜率作為輸入特徵,反射界面種類作為輸出(裂縫為1,鋼筋為0),再以前述之數值模擬及模型試驗數據對網路進行訓練。當產生新的敲擊回音訊號時,只要將其回音相位及相位斜率輸入此類神經網路分類器,便可由輸出值判斷反射界面的種類。 為測試前述分類器之準確性,本研究中另內含傾斜裂縫及3公分深鋼筋的模型試驗訊號,以及內含25公分深水平裂縫及15公分深圓柱鋼筋的模擬及模型試驗訊號代入各分類器,發現一元、二元線性分類器及類神經網路皆能正確判別反射界面種類,顯示本研究方法之有效性。 | zh_TW |
dc.description.abstract | Impact-echo is widely used on inspecting the defect in concrete. Through the Fourier transform of surface vibration signal, inspector can use peak frequency to calculate the depth of the defect. However, peak frequency cannot determine whether the reflector is a crack or steel.
The study develops a method to automatically determine whether the echo comes from a crack or a steel bar. As an impact is applied on the concrete surface, compression waves will be generated. As a compression wave encounters a free interface, it is reflected as a tension wave. On the other hand, if it encounters a fixed boundary, it is reflected as compression wave. Hence, the phase of the impact echo signal contains the information about the type of the interface. Therefore, this study tries to develop a reflector classifier based on the phase spectrum of the impact echo signal. Finite element analysis and model tests were conducted on specimens containing cracks or steel bars at different depth, ranging from 8 to 12 cm for cracks and 4 to 6 cm for steel bars. Fourier transforms were applied to the response signals and the phase spectrum for each signal was obtained. A 2D scatter plot was generated using the phase and the slope of phase at the echo frequency. It is found that the data points were divided into two separated groups. Hence, the phase and the slope of phase at the echo frequency were used as the input features for the classifier in this study. Two types of classification methods were used in this research, namely, the linear classification and the artificial neural network (ANN). In the linear classifier, a straight line is drawn in the phase | en |
dc.description.provenance | Made available in DSpace on 2021-06-15T16:16:45Z (GMT). No. of bitstreams: 1 ntu-104-R02543004-1.pdf: 2324763 bytes, checksum: 9bd255412a0ac2b9675d86a07aab49dc (MD5) Previous issue date: 2015 | en |
dc.description.tableofcontents | 口試委員會審定書 #
致謝 II 摘要 III Abstract V 目錄 VII 圖目錄 IX 表目錄 XIV 第一章 前言 1 1-1研究動機 1 1-2文獻回顧 2 1-3內容大鋼 3 第二章 敲擊回音法之原理 4 2-1 應力波傳行為 4 2-2 敲擊回音法 6 2-3 敲擊回音法試驗參數 7 2-3-1 敲擊源 7 2-3-2 總取樣時間 9 2-3-3 取樣時距 10 2-4 敲擊回音法用於異質材料之檢測分析 10 第三章 敲擊回音相位 19 3-1 傅立葉頻譜相位 19 3-2 一維波傳在不同界面條件下之相位 20 3-3 不同介質反射面對敲擊回音相位之影響 21 3-4 影響相位斜率之因素 22 第四章 數值模擬 38 4-1 有限元素法軟體介紹 38 4-2 有限元素分析步驟 39 4-3 數值算例結果與分析 42 4-3-1 數值算例 42 4-4 小結 43 第五章 模型試驗 54 5-1 模型試體 54 5-2 實驗設備及參數設定 55 5-2-1 實驗設備 55 5-2-2 參數設定 56 5-3 實驗結果 56 5-3-1 模型試驗一 56 5-3-2 模型試驗二 57 5-3-3 模型試驗三 58 5-3-4模型試驗四 59 5-4 小結 59 第六章 裂縫與鋼筋相位訊號之分類 85 6-1 線性分類法 85 6-1-1 線性分類器 85 6-1-2 測試結果 86 6-2 類神經網路分類法 87 6-2-1 類神經網路器 87 6-2-2 測試結果 88 第七章 結論 101 參考資料 103 | |
dc.language.iso | zh-TW | |
dc.title | 鋼筋與裂縫敲擊回音訊號之辨識 | zh_TW |
dc.title | Recognition of Reinforcing Bars and Cracks Based on Impact-Echo Phase Analysis | en |
dc.type | Thesis | |
dc.date.schoolyear | 103-2 | |
dc.description.degree | 碩士 | |
dc.contributor.oralexamcommittee | 林宜清(Yi-Ching Lin),童建樺(Jian-Hua Tong) | |
dc.subject.keyword | 結構安全評估,非破壞檢測,敲擊回音法,相位,混凝土, | zh_TW |
dc.subject.keyword | Safety Evaluation,Nondestructive Testing,Impact-echo,Phase,Concrete, | en |
dc.relation.page | 104 | |
dc.rights.note | 有償授權 | |
dc.date.accepted | 2015-08-17 | |
dc.contributor.author-college | 工學院 | zh_TW |
dc.contributor.author-dept | 應用力學研究所 | zh_TW |
顯示於系所單位: | 應用力學研究所 |
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