Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/91287
標題: Digital image correlation for large deformation measurement
數位影像相關性於大變形量測之應用
作者: 曾舜隆
Shun-Long Ceng
關鍵字: digital image correlation
shape interpolation function
large deformation
connected component labeling
數位影像相關法
形狀內插函數
牛頓法
大變形
連通區域標 記
引用: [1] Peters, W. H. and W. F. Ranson. 'DIGITAL IMAGING TECHNIQUES IN EXPERIMENTAL STRESS ANALYSIS.' Optical Engineering 21(3): 427-431. (1982). [2] Bruck, H. A., et al. 'Digital image correlation using Newton-Raphson method of partial differential correction.' Experimental Mechanics 29(3): 261-267. (1989). [3] Zhou, P. and K. E. Goodson. 'Subpixel displacement and deformation gradient measurement using digital image/speckle correlation(DISC).' Optical Engineering 40(8): 1613-1620. (2001) [4] Yao, X. F., et al.. 'Full-field deformation measurement of fiber composite pressure vessel using digital speckle correlation method.'Polymer Testing 24(2): 245-251. (2005) [5] Yaofeng, S. and J. H. L. Pang. 'Study of optimal subset size in digital image correlation of speckle pattern images.' Optics and Lasers in Engineering 45(9): 967-974. (2007). [6] Chen, J., et al. 'Deformation measurement across crack using two-step extended digital image correlation method.' Optics and Lasers in Engineering 48(11): 1126-1131.(2010) [7] Joy, K. I. 'Catmull-Rom-Spline.' On-Line Geometric Modeling Notes:1-4. (2002). [8] 劉懷恒 '結構及彈性力學有限單元法' 西北工業大學出版社,,, 2007-8-1。 [9] 任學平, 高耀東,'彈性力學基礎及有限單元法',華中科技大學出版社,2007-10-1。 [10] Gavin, H. P. 'The Levenberg-Marquardt method for nonlinear least squares curve-fitting problems.' :1-17. (2013). [11] Pan, B., et al. 'Digital image correlation using iterative least squares and pointwise least squares for displacement field and strain field measurements.' Optics and Lasers in Engineering 47(7-8): 865-874.(2009). [12] Herbert Reismann, Peter S. Pawlik ,'ELASTICITY Theory and Applications',新智出版社有限公司,1980。
摘要: The present study has developed a plane displacement measurement system based on a digital image correlation method. For these purposes,the strain of large deformation was defined as 40%. A series of analyses was performed on the images before and after deformation, including correlational analysis, connected component labeling, and shape interpolation function analysis. Furthermore, optimizations were made employing displacement equations and brightness of transformation models, in conjunction with Newton's method. Iterative methods were used to find the underwent displacement of an object after deformation,finally determining the surface displacement field and the strain field. However, the use of Newton's method iteration methods requires inputting an initial value. These values must first be derived by marking each connected area with connected component labeling, then constructing a grid with this data and corresponding the before-after images based on this grid. The methods of this study were to print prepared images onto the object being tested, then to record digital images of the object before and after deformation. Analysis was conducted with software based on digital image correlation theory and shape function, to determine the displacement field of the object's surface,concluding with a discussion of the displacement field derived from analysis, and possible improvements to be made for future investigations.
本文提出應用數位影像相關法建立一套平面位移量測系統。由於本文的目的是計算大變形所以先定義大變形的應變 40% 針對待測物。擷取影像進行相關性分析、區域連通演算法以及形狀函數分析,再經由位移方程式及亮度轉換模型配合牛頓法理論進行此位移方程式之優化,透過迭代運算求得物體表面變形後位移之次像素精度後,最終得到物體表面位移場及應變場變化。然而如果使用牛頓迭代的話就必須給定初始值,而這些初始值的來源則必須先利用連通區域標記法將每一個連通的區域標註記號,然後再利用這些編號的特性找出影像內每一個網格點,有了變形前後的網格點後就能很快地找到這些位移的初始值。實驗部分則是先將製作好的圖案印在要實驗的物體上,再利用數位攝影機拍攝物體在受力前後的影像,並透過數位影像相關性理論以及形狀函數所撰寫的數位影像分析程式,並直接推算物體表面位移場的變化。最後結論則是分析計算得到的位移場以及探討該如何改進缺點。
URI: http://hdl.handle.net/11455/91287
文章公開時間: 2015-05-11
Appears in Collections:機械工程學系所

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