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完整後設資料紀錄
DC 欄位 | 值 | 語言 |
---|---|---|
dc.contributor.advisor | 劉佩玲(Pei-Ling Liu) | |
dc.contributor.author | Chen-Yeh Yen | en |
dc.contributor.author | 顏辰燁 | zh_TW |
dc.date.accessioned | 2021-06-17T03:09:48Z | - |
dc.date.available | 2019-08-01 | |
dc.date.copyright | 2018-08-01 | |
dc.date.issued | 2018 | |
dc.date.submitted | 2018-07-20 | |
dc.identifier.citation | [1] M. Sansalone and N. Carino, 'Impact-Echo: A Method for Flaw Detection in Concrete Using Transient Stress Waves', NBSIR 86-3452, National Bureau of Standards, Washington, DC,' PB 87-10444/AS (National Technical Information Service, Springfield, MA, 1986)1986.
[2] C. Cheng and M. Sansalone, 'The impact-echo response of concrete plates containing delaminations: numerical, experimental and field studies,' Materials and Structures, vol. 26, no. 5, pp. 274-285, 1993. [3] Y. Lin and M. Sansolone, 'Detecting flaws in concrete beams and columns using the impact-echo method,' Materials Journal, vol. 89, no. 4, pp. 394-405, 1992. [4] Y. Lin and M. Sansalone, 'Transient response of thick rectangular bars subjected to transverse elastic impact,' The Journal of the Acoustical Society of America, vol. 91, no. 5, pp. 2674-2685, 1992. [5] Y. Lin and M. Sansalone, 'Transient response of thick circular and square bars subjected to transverse elastic impact,' The Journal of the Acoustical Society of America, vol. 91, no. 2, pp. 885-893, 1992. [6] P.-L. Liu, B.-L. Yeh, and C.-Y. Yiu, 'Imaging of Concrete Defects Using Wlastic Wave Tests,' Bulletin of the College of Engineering, no. NTU 91: 41-50, 2004. [7] C. Colla and R. Lausch, 'Influence of source frequency on impact-echo data quality for testing concrete structures,' Ndt & E International, vol. 36, no. 4, pp. 203-213, Jun 2003, Art. no. Pii s0963-8695(02)00062-2. [8] P. Yeh, 'The time–frequency domain analysis and image method of the impact-echo method,' Taipei: National Taiwan University, 2006. [9] 林佳慶, '經驗模態分解法於敲擊回音法之應用,' 臺灣大學應用力學研究所學位論文, pp. 1-194, 2007. [10] M. Sansalone, Theory and Operation Manual for the Impact-Echo Field System. Cornell University, 1992. [11] 林宜清, 陳真芳, and 蔡聖德, '混凝土構件幾何形狀對波速之影響,' 1994. [12] A. Gibson and J. S. Popovics, 'Lamb Wave Basis for Impact-Echo Method Analysis,' Journal of Engineering Mechanics, vol. 131, no. 4, pp. 438-443, 2005. [13] Y. L. Meng-Tzong Hu and C. Chia-Chi, 'Method for Determining Internal P-Wave Speed and Thickness of Concrete Plates,' Materials Journal, vol. 103, no. 5, 9/1/2006. [14] C. Prada, D. Clorennec, and D. Royer, 'Local vibration of an elastic plate and zero-group velocity Lamb modes,' The Journal of the Acoustical Society of America, vol. 124, no. 1, pp. 203-212, 2008. [15] O. Baggens and N. Rydén, 'Systematic errors in Impact-Echo thickness estimation due to near field effects,' Ndt & e International, vol. 69, pp. 16-27, 2015. [16] S. G. Mallat and Z. Zhifeng, 'Matching pursuits with time-frequency dictionaries,' IEEE Transactions on Signal Processing, vol. 41, no. 12, pp. 3397-3415, 1993. [17] J. Achenbach, 'Wave Propagation in Elastic Solids North,' ed: Holland Publishing Company, Amsterdam, 1973, pp. 226-236. [18] S. D. Holland and D. E. Chimenti, 'Air-coupled acoustic imaging with zero-group-velocity Lamb modes,' Applied Physics Letters, vol. 83, no. 13, pp. 2704-2706, 2003. [19] R. R. Aggarwal, 'AXIALLY SYMMETRIC VIBRATIONS OF A FINITE ISOTROPIC DISK .1,' (in English), Journal of the Acoustical Society of America, Article vol. 24, no. 5, pp. 463-467, 1952. [20] R. R. Aggarwal, 'AXIALLY SYMMETRIC VIBRATIONS OF A FINITE ISOTROPIC DISK .2,' (in English), Journal of the Acoustical Society of America, Article vol. 24, no. 6, pp. 663-666, 1952. [21] R. R. Aggarwal, 'AXIALLY SYMMETRIC VIBRATIONS OF A FINITE ISOTROPIC DISK .3,' (in English), Journal of the Acoustical Society of America, Article vol. 25, no. 3, pp. 533-535, 1953. [22] R. R. Aggarwal and E. A. G. Shaw, 'AXIALLY SYMMETRIC VIBRATIONS OF A FINITE ISOTROPIC DISK .4,' (in English), Journal of the Acoustical Society of America, Article vol. 26, no. 3, pp. 341-342, 1954. [23] J. O. Hallquist, LS-DYNA Keyword User's Manual. Californa: Livermore Software Technology Corporation, 2003. [24] Y. Lin, M. Sansalone, and N. J. Carino, 'Finite Element Studies of the Transient Response of Plates Containing Flaws,' Int’l Adv. In Nondestructive Testing, pp. 313-336, 1990. [25] W. Goldsmith, 'Impact-the theory and physical behaviour of colliding solids, Edward Arnold Ltd,' London, England, 1960. [26] M. Brissaud, 'CHARACTERIZATION OF PIEZOCERAMICS,' (in English), Ieee Transactions on Ultrasonics Ferroelectrics and Frequency Control, Article vol. 38, no. 6, pp. 603-617, Nov 1991. [27] N. Guo, P. Cawley, and D. Hitchings, 'THE FINITE-ELEMENT ANALYSIS OF THE VIBRATION CHARACTERISTICS OF PIEZOELECTRIC DISKS,' (in English), Journal of Sound and Vibration, Article vol. 159, no. 1, pp. 115-138, Nov 1992. | |
dc.identifier.uri | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/69154 | - |
dc.description.abstract | 敲擊回音法為應用於混凝土結構檢測中最為廣泛的非破壞檢測技術,其原理為於待測物表面敲擊激發應力波,以位移感測器量取敲擊點附近之縱向位移訊號,經由傅立葉轉換將位移時間域訊號轉換為頻率域訊號,即可由頻譜尖峰頻率判斷試體內部特徵。然而,由敲擊回音法所量測試體厚度與理論值卻存有一定比例誤差,稱之為視波速現象,使檢測人員產生量測上的不準確因素。
本研究目的旨在探討敲擊回音法理論頻率與實際量測所得頻率尖峰之差異,即視波速因子beta。分析對象分別為圓形,方形與無限大平板三種試體。利用Rayleigh-Lamb波動理論分析無限大扁平板之振動模態;以Aggarwal所提圓盤振動理論分析圓形試體振動模態;以及藉由有限元素軟體分析圓形及方形試體之振動模態。 本文考慮三種參數對敲擊回音尖峰頻率之影響:訊號取樣總長、材料常數與寬高比。首先,分析試體材料常數之影響,將Rayleigh-Lamb波動方程整理並化簡,將無限大平板之beta表示為柏松比函數,即此beta值只與試體柏松比相關,並以有限元素軟體模擬驗證理論值。 接著,分析訊號擷取時長影響,由數值模擬結果指出,當訊號擷取時長低於一門檻時,不論圓形或方形試體,因應力波於試體側向傳遞次數甚低,反應類似於一無限大平板中傳遞情形,因而所得結果與以Rayleigh-Lamb波動理論所得到beta值接近。當訊號擷取時長大於上述門檻後,此時應力波於試體側向傳遞次數增高,以致激發試體各式模態並反應於頻譜上,此時頻率尖峰對應試體模態振動。 前述門檻主要受試體幾何形狀與寬高比影響。本研究嘗試圓形及方形試體2 ~ 10之寬高比變化,數值模擬結果指出,寬高比4以上之圓形試體,模擬時長為底部回波週期40倍時約為激發試體模態振動之時間門檻。低於此寬高比之試體於相同訊號取樣長度時則易激發試體模態振動,進而影響所量測頻率,造成估算厚度之誤差。方形試體對於訊號取樣總長改變則無明顯反應,同一寬高比試體,由短時至長時進行量測,所取得頻率尖峰對應beta值皆十分相近。 寬高比亦對試體振動模態影響甚劇。於長時量測時,利用圓盤振動理論計算出各寬高比圓試體所對應模態頻率理論解與繪製其振態,並觀察到各寬高比圓試體頂部位移第一圈跨零點半徑均落於0.60 ~ 0.66倍試體厚度範圍內之現象。 綜上所述,建議進行敲擊回音試驗時可將量測訊號交由電腦分析其短時至長時反應,觀察頻率尖峰改變情形,並挑選短時分析結果,使用Rayleigh-Lamb理論所提供beta值修正試體厚度。 | zh_TW |
dc.description.abstract | Impact-echo method is the most widely used nondestructive testing technique in the testing of concrete structure. Hitting the surface of the target and creating a stress wave, we can measure the vertical displacement signal near the impact point in time domain. We can determine the characteristics inside the target by studying the peaks’ frequency on the spectrum, transformed from time domain by Fourier transform. However, it exists a distinctive error between the results of the target’s thickness measured with impact-echo method and the theoretical value, which is called apparent velocity, suggesting an uncertain factor in the measuring process.
The main purpose of this research is to investigate the difference between the peak of the theoretical frequency of impact-echo method and the frequency obtained by measurement, which is called apparent velocity factor beta, by analyzing circular, rectangular and infinitely large plates. Using Rayleigh-Lamb wave theory to analyze the vibration modal of infinitely large plates, Aggarwal’s theory of vibrating disks to analyze the vibration modal of circular plates and a finite element software to analyze the vibration modal of circular and rectangular plates. This research took into consideration the influence of three parameters toward impact-echo peak frequency: sampling time, material properties and aspect ratio. First analyzing the influence of the material properties, by simplifying Rayleigh-Lamb wave equation, expressing the beta of the infinitely large plate with Poisson’s ratio, making this beta only be related to Poisson’s ratio, and verifying this theoretical value with a finite element software. Then, by analyzing the influence of sampling time, we can see from the result of numerical simulations that when the sampling time is shorter than a threshold, since the number of stress wave’s lateral transfer is low, it reacted like if it was transferring on an infinitely large plate, whether the specimen is circular or rectangular, thus the result is similar to the beta value obtained by Rayleigh-Lamb wave theory. When the sampling time is above the threshold, the number of lateral transferring of stress wave in the specimen is increasing, leading to the exciting of all kinds of modals of the specimens and reflecting them on the frequency spectrum, and in this circumstance, the frequency peak corresponds to the specimen’s vibration modal . The above mentioned threshold is mainly decided by the shape and the aspect ratio of the specimen. This research tries to vary the aspect ratio of circular and rectangular specimens between 2~10, according to the results of numerical simulation, circular specimens with an aspect ratio above 4 have the threshold time of exciting the specimens modal vibration when the termination time is approximately 40 times the length of cycle of the specimens’ bottom reflected wave. Specimens with an aspect ratio below this threshold with the same sampling time tend to excite its vibration modal, influencing the measured frequency, leading to error in the estimation of the thickness. On the other hand, rectangular specimens do not show obvious difference faced with different sampling time. Measuring specimens with the same aspect ratio from short to long sampling time, we obtain frequency peaks corresponding very well to beta. Aspect ratio also greatly influences the vibration modal of specimens. When measuring over a long period, using circular plate vibration theory, we can calculate the theoretical value of modal frequency corresponding to various aspect ratio of circular plates and plot its vibration mode. We can observe that the zero-crossing point’s radius of the displacement’s first loop of the circular specimens’ top all lies within 0.60~0.66 times the thickness of the specimens. To sum up, it is suggested to use the computer to analyze the measured signals’ reactions from a short period of time to a long period of time when applying impact echo tests and observe the difference of frequency peaks and pick the results with short analyzing time to correct the thickness of the specimens with Rayleigh-Lamb theory. | en |
dc.description.provenance | Made available in DSpace on 2021-06-17T03:09:48Z (GMT). No. of bitstreams: 1 ntu-107-R04543058-1.pdf: 4031596 bytes, checksum: b96d637bf60729391f8b3100a82ec0bb (MD5) Previous issue date: 2018 | en |
dc.description.tableofcontents | 致謝 I
摘要 II Abstract IV 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全文簡介 4 第二章 敲擊回音法 5 2.1應力波傳遞行為 5 2.2敲擊回音法 8 2.3視波速現象 10 2.4 Matching Pursuit匹配追蹤法 12 第三章 對稱振動模態理論之應用 18 3.1 Rayleigh-Lamb波動方程式 18 3.1.1第一階對稱( )振動模態 19 3.1.2 振動頻率之參數分析 20 3.2均質等向性圓盤之軸對稱振動理論 22 3.2.1滿足不同邊界條件時之應力差異 27 3.2.2解頻率方程式無窮多根之選擇 30 第四章 數值分析 37 4.1有限元素分析 37 4.1.1有限元素法軟體介紹 38 4.1.2有限元素法分析步驟 40 4.1.3敲擊回音模擬參數 46 4.2無限邊長平板之視波速因子 50 4.2.1柏松比改變之影響 51 4.3有限邊長平板之視波速因子 54 4.3.1圓形試體 55 4.3.1.1模擬總時長之選擇 55 4.3.1.2寬高比之影響 63 4.3.1.3振動模態頂部位移第一跨零點分析 67 4.3.2方形試體 73 4.3.2.1模擬總時長之選擇 74 4.3.2.2寬高比之影響 79 第五章 結論與未來展望 154 5.1結論 154 5.2未來展望 156 參考文獻 157 | |
dc.language.iso | zh-TW | |
dc.title | 敲擊回音視波速現象之探討 | zh_TW |
dc.title | A study of apparent velocity of the impact-echo test | en |
dc.type | Thesis | |
dc.date.schoolyear | 106-2 | |
dc.description.degree | 碩士 | |
dc.contributor.oralexamcommittee | 郭茂坤(Mao-Kuen Kuo),林宜清(Yi-ching Lin) | |
dc.subject.keyword | 敲擊回音法,視波速因子,振動模態,柏松比,訊號取樣總長,寬高比, | zh_TW |
dc.subject.keyword | Impact-echo method,Empirical correction factor,Vibration modal,Poisson’s ratio,Sampling time,Aspect ratio, | en |
dc.relation.page | 159 | |
dc.identifier.doi | 10.6342/NTU201801531 | |
dc.rights.note | 有償授權 | |
dc.date.accepted | 2018-07-23 | |
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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