本論文是使用超音波檢測技術對裂縫進行探傷，主要重點在於了解超音波系統對於非簡單幾何外型之表面裂縫的探知能力，並且應用其檢測技術於裂縫開口荷重的量測。
本實驗室已建立一套超音波自動化檢測系統，使用該系統對斜向、曲面、轉折的表面裂縫（缺陷）進行檢測，模擬真實現場情況，經過實驗，得到的結果為超音波能掌握裂縫之表面形狀與其走向，在深度方面，由於真實裂縫於零負載下屬閉合狀態且裂縫是於材料晶粒間之界面成長，有不定方向性，故對於產生尖端繞射回波有一定的影響，經由反覆量測與排除奇異點後可得到與真實裂縫斷面相近的尺寸。
突破以往使用應變規量測裂縫開口荷重的缺點，藉由不同負載下，裂縫尖端的角度變化造成超音波音束反射能量的增減來推斷其開口荷重。由實驗得知在不同的量測相對位置會得到不同曲線形式的回波能量圖，但圖形斜率的變化點將發生在同一負載下，經過與應變規比較後，得知該負載即為裂縫之開口荷重。

Abstract
This thesis is using ultrasonic detected skill on fatigue crack. The point is on realizing the ability of ultrasonic system for detecting
un-simple geometry shape surface crack and the application of ultrasonic detected skill on measurement of open load.
Our lab has established an automatic ultrasonic testing system which can examine oblique、camber and turned crack for simulating the situation on work field. After experiments, the result is that ultrasonic testing system can handle the surface shape and way of surface crack. In depth aspect, because of real crack is closure below unloading and crack growth in the interface of material pellet, producing diffraction wave from tip is been influenced. We can almost get real crack dimension accurately by way of repeating measurement and eliminate odd point.
To break through the defect of adopting strain gage for measuring open load, by way of the change of ultrasonic reflection energy ,cause of the difference of crack tip angle in different loading, to judge the open load. We can obtain different type of echo curve in diverse condition, but the turning point of slope of ultrasonic reflection energy will occur in the same load and the load is the open load of the crack.

參考文獻

[1] 謝政倚，“超音波雙探頭法成像研究”，國立中正大學應用地球物理研究所論文，中華 民國90年6月。
[2] 趙育毅，“聚焦式超聲波換能器應用於材料檢測”，國立成功大學機械工程研究所論文，中華民國91年7月。
[3] Krautkramer,Ultrasonic Testing of Materials,Springer-Verlage Berlin Heidlberg New York (1969).
[4] Michael Berke, Krautkrämer GmbH & Co., Hürth, “Nondestructive Material Testing with Ultrasonics - Introduction to the Basic Principles ”, The e-Journal of Nondestructive Testing & Ultrasonics,Issue Vol. 5 No. 9 , (2000).
[5] W. J. McGonnagle著，侯國琛譯，非破壞性檢測法，徐氏基金會出版，中華民國85年4月。
[6] 葉競榮，徐鴻發，超音波檢測法中級，中華民國非破壞檢測協會，中華民國79年2月。
[7] Elber,Wolf,”The Significance of Fatigue Crack Close,”ASTM STP
486,pp144-147,1971.
[8]J.C.Newman,Jr.and I.S.Raju, ”Stress Intensity Factor Equations for Cack in Three-Dimensional Finite Bodies”,NASA Technical Memorandom 83200,,pp.1-49,1981
[9]Elber,w,”fatigue Crack Closure Under Cyclic Tension,”Engineering
Fracture Mechanics,Vol2,1970,pp.37-45.
[10]Suresh, S. and Ritchie,R.O.,”Propagation of Short Fatigue Cracks.”International Metallurgical Reviews,Vol.29,pp.445-476.
[11]Budiansky,B.and Hutchinson,J.W.,”Analysis of Closure in Fatigue Crack Growth.”Journal of Applied Mechanics, Vol.45, 1978, pp.267-276.
[12]Allison,J.E.,”The Measurement of Crack Closure During Fatigue Crack Growth”.ASTM STP 945,American Society for Testing and Materials,Philadelphia,1988,pp.913-933.
[13]Sharpe, W.N., and Grandt, A.F., ASTM STP 590,American Society for testing and Materials, Philadelphia,1976,pp.302-320.
[14] Lawson, S., and Parker, G.A., "Automatic detection of defects in
industrial ultrasound images using a neural network", Proc. of SPIE
vol. 2786, pp. 37-47 (1996)
[15] N. Trimborn, “The Time-of-Flight-Diffraction-Technique”, The e-Journal of Nondestructive Testing & Ultrasonics,Issue Vol. 2 No.9 (1997).
[16] Silk, M.G., “The use of diffraction based time-of-flight measurements to locate and size defects”, Brit. J. of NDT, vol. 26, pp 208-213. (1984)
[17] T. Just, G. Csapo, “Ultrasonic crack depth measurement of surface bracking cracks in piping”, The e-Journal of Nondestructive Testing & Ultrasonics,Issue Vol. 2 No. 9 (1997).
[18]Elber,Wolf ,”The Significance of Fatigue and crack close,”ASTM STP 486,pp144-147,1971
[19] 屠耀元,“數位信號處理端點回波聲程測量自身高度方法的研究” http://www.chsndt.com/article/height_0.htm。
[20] 王國榮，新觀念的Visual Basic 6.0 教本，旗標，中華民國90年8月。
[21] 吳學文，黃啟貞，陳必貫，葉競榮，超音波檢測法初級，中華民國非破壞檢測協會，中華民國77年1月。
[22] 劉家勤，“非均勻應力分佈之在鋼板中之疲勞裂縫進展行為探討”，國立成功大學造船暨船舶機械工程研究所論文，中華民國91年7月。
[23] 李家彰，”表面裂縫之超音波自動化檢測系統開發”， 國立成功大學造船暨船舶機械工程研究所論文，中華民國92年6月。
[24] 詹奇峰，”應力集中效應對表面疲勞裂縫之影響”， 國立成功大學造船暨船舶機械工程研究所論文，中華民國92年6月。