摘 要

光彈應力分析是一種很普遍且有很多研究的技術。光彈性實驗有兩組有用的基本數據：一組為等傾線，即具有相同主應力方向點之軌跡，反映出的是主應力方向；一組為等色線，即具有相同主應力差值點之軌跡，反映出的是主應力差值。此兩組數據為光彈應力分析中之重要參數。
本文主要的目的是發展各種自動化光彈分析方法來獲得更精確的條紋序數與主應力方向角以及比較各種發展出來的自動化光彈分析方法，最後經圓盤徑向壓力測試獲得的結果與理論解做比較可證明這些方法的可行性與準確性。因此，在擷取光彈影像後所做的影像處理方面，提供了五種影像處理的方法，在論文中分析兩組光彈參數所採用的是 影像處理法；在處理主應力方向角方面，以相位移法(Phase-shifting)的邏輯為基礎，發展出二波長法、二力法以及Min-Max法，有效地改善受到等色線條紋影響的問題；在處理條紋序數方面，發展出二波長法與二力法，並且在獲得全場性的條紋序數分佈圖之後，再經過二次曲面密合的處理，將原本在整數級與半整數級條紋處誤差較大的數值做有效的修正，使得處理之後的條紋序數分佈更為精確。

Abstract

The photoelastic stress analysis is a technology with many researches focused on it. There are two useful and basic data in photoelastic experiments: one is isoclinics, which is the locus of points with the same principle stress directions; the other is isochromatics, which is the locus of points with the same principle stress difference. These data are the important parameters in photoelastic stress analysis.
The main purpose of this article is to develop various analytic methods of automatic photoelasticity which can get very accurate data of fringe orders and principle stress directions and to compare with them. Finally, the results obtained for disk-in-compression tests presented here in comparison with theoretical solutions demonstrate that these methods are both simple to use and very accurate. Hence, after acquiring photoelastic images, I offered five methods of image processing procedure. I adopted image processing procedure to analyze the data of two photoelastic parameters in this article. In the case of the principle stress directions, I developed the analytic methods of Two-Wavelengths and Two-Loadings and Min-Max based on phase shifting algorithm. These methods could improve the influence of isochromatics more effectually. In the case of fringe orders, I developed the analytic methods of Two-Wavelength and Two-Loadings. After we obtained the whole-field distributions of fringe orders, I used the quadric fitting to correct the big errors of data in integral and half fringe orders more effectually and it could make the distributions of fringe orders more accurate.

參考文獻

[1]Patterson, E.A., “Automated Photoelastic Analysis”, Strain, Vol.24, Feb., pp.15~20(1988).
[2]Coker, E.G. and Filon, L.N.G., “Treatise on photoelasticity”, University Press, Cambridge, U.K.,(1931).
[3]Paipeitis,S.A. and Holister, G.S., “Photoelasticity in engineering practice”, Elsevier Applied Science Publishers, London,(1935).
[4]Oppel, G., “Polarisationoptische untersuchang rammerlicher spanmings und deliunggzustande”, Forsh. Geb. Ingenieurw, 7, pp. 240~248(1936).
[5]賴耿陽, “應力應變解析原理”, 復漢出版社.(1987)
[6]Allison, I.M. and Nurse, P., “Optimal data acquisition for an antomatic Polariscope”, 7th All-Union Conference on Photoelasticity, Tallinn, Nov., Proc. Pt. 1, pp 93~105(1971).
[7]Allison, I.M. and Nurse, P., “Automatic acquisition of engineering Measurements”, Inst. Mar. Engrs., London, pp. 203~207(1972).
[8]Redner, A.S., “A New Automatic Polariscope System”, Exp. Mech., Vol. 14, December, pp. 486~491(1974).
[9]Redner, A.S., “Photoelastic Measurements by Means of Computer-Assisted Spectral-contents Analysis”, Exp. Mech., June, pp. 148~153(1985).
[10]Haake, S.J., and Patterson, E.A., “Photoelastic Analysis of Frozen Stressed Specimens Using Spectral-contents Analysis”, Exp. Mech., Vol. 32, Sep., pp. 266~272(1992).
[11]Srinath, L.S. and Sarma, A.V.S.S.S.R., “Determination of Integral Fringe Order in Photoelasticity”, Exp. Mech., Vol. 13, Mar., pp. 138~141(1973).
[12]Mueller, R.K. and Saackel, L.R., “Complete Automatic Analysis of Photoelastic Fringes”, Exp. Mech., Vol. 19, July, pp. 245~252(1979).
[13]Seguchi, Y., Tomita, Y. and Watanabe, M., “Computer Aided Fringe Pattern Analysis – A Case of Photoelastic Fringe”, Exp. Mech., Vol. 19, Oct., pp. 362~370(1979).
[14]Voloshin, A.S. and Burger, C.P., “Half Fringe Photoelasticity – A New Approach to Whole Field Stress Analysis”, Exp. Mech., Vol.23, pp. 304~314(1983).
[15]Umezaki, B., Tamaki and Takahashi, S., “Automatic Stress Analysis from Photoelastic Fringes due to Image Processing Using a Personal Computer”, Proc. Soc., Photo., Vol. 504, pp. 127~134(1984).
[16]Yao, J.Y., “Extracting isoclines using image-processing techniques”, Exp. Tech., Vol. 11, Oct., pp. 30~31(1987).
[17]Yao, J.Y., “Digital Image Processing and Isoclinics”, Exp. Mech., Vol. 30, Sep., pp. 264~269(1990).
[18]Mawatari, A., Takashi, M. and Toyoda, Y., “Whole-Area Photoelastiv Analysis by Image Processing on the Principal Stress Direction and Saparation of Isochromatics from Isoclinics”, Trans. Of JSME., Ser. A, Vol. 55, N0. 514, pp. 1423~1428(1989).
[19]Patterson, E.A. and Wang, Z.F., “Towards Full Field Automated Photoelastic Analysis of Complex Components”, Strain, Vol. 27, May, pp. 49~53(1991).
[20]Sarma, A.V.S.S.S.R., Pillai, S.A., Subramanian, G. and Varadan, T.K., “Computerized Image Processing for Whole-field Determination of Isoclinics and Isochromatics”, Exp. Mech., Vol. 32, Mar, pp. 24~29(1992).
[21]Srinath, L.S. and Sarma, A.V. S.S.S.R., “ Dtermination of Integral Fringe Orders in Photoelasticity”, Exp. Mech., Vol. 13, Sep., pp. 138~141(1973).
[22]Zandman, F., “Photostress analysis”, Product Engineering, Vol.2(1959).
[23]Robert, A.J., “New method in Photoelasticity”, Exp. Mech., Vol. 7, pp. 224~232(1967).
[24]Frocht, M.M., “Photoelasticity”, Vol.I, II, John Wiley and Sons, New York(1948).
[25]Dally, J.W. and Riley, W.F., “Experimental Stress Analysis”, 3rd Ed., McGraw Hill(1991).
[26]Ming Yue and Zhang Fang, “Whole-Field Measurement of Isochromatic and Isoclinic Parameters”, Journal of Exp. Mech., Vol. 7, No. 2, June, pp. 115~121(1992).
[27]David Broek, “Fundamental Engineering Fracture Mechanics”.
[28]T.Y.Chen, “Recent advances in digital photoelasticity”, Trends in Optical Nondestructive Testing and Inspection,pp.533~544.
[29]林建宏、陳元方, “自動化光彈研究之分析”(1995).
[30]G.Petrucci, “Full-field Automatic Evaluation of an isoclinic Parameter in White Light”, Experimental mechanics, pp.420~426(1997).
[31]M.J.Ekman and A.D.Nurse, “Absolute Determination of the Isochromatic Parameter by Load-stepping Photoelasticity”, Experimental mechanics, pp.189~195(1998).
[32]N.Plouzennec and A.Lagarde, “Two-wavelength Method for Full-field Automated Photoelasticity”, Experimental mechanics,pp.274~277 (1999).