Measurement of interior displacement field by an embedded laser speckle photography.

通过嵌入式激光散斑摄影测量内部位移场。

• 批准号: 08650056
• 负责人: MACHIDA Kenji
• 金额: $ 1.41万
• 依托单位: Science University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650056/
• 关键词: Speckle Photography; Young's fringe; 2-D Fourier Transform; Interior Displacement; Image Processing; Mixed Mode; Stress Intensity Factor; Interface Crack; ヤングスフリンジ; スペックル法; 仮想き裂進展法; 変位外挿法

The image-processing system based on a 2-D Fourier transform and iteration using the bounded Newton- Raphson algorithm is presented for the analysis of Young's fringes patterns created from double-exposure speckle photography. The fringe spacing and orientation are determined using only one Young's fringes pattern without any other diffraction halo patterns. This image-processing system enables us to analyze the fringe spacing and orientation or Young's fringes pattern with high accuracy and speed. Displacement in the near-crack-tip fields was measured on transparent compact normal and shear specimens made of Plexiglas under mixed-mode loading by speckle photography. The stress-intensity factors (SIF) along the crack front were cvaluated by the displacement extrapolation. A finite element analysis was carried out on the same specimens. The accuracy of SIF was discussed by comparison between the virtual crack extension method and the displacement method for mixed-mode problems. The variation of SIF with load application angle was discussed on different planes from the free surface to the center of the specimen. SIF are nearly uniform from the midsection to a depth of 3mm of the specimen. Therefore, it is sufficient to measure SIF at a depth of 3mm of the specimen. SIF at the central part of specimen largely differ from SIF obtained by 2-D plane strain analysis. SIF of homogeneous material under mixed-mode loading can be measured with high accuracy by embedded speckle photography. This method was lied to measure SIF of interface crack problems. Steel and an epoxy resin were used as dissimilar materials. The displacement along the crack lines at the free surface was measured by speckle photography. At the free surface of the specimen, SIF obtained by speckle photography agree with SIF obtained by finite element analysis. SIF of the interface crack can also be evaluated by speckle photography.

提出了基于二维傅立叶变换和使用有界牛顿拉夫森算法迭代的图像处理系统，用于分析由双曝光散斑摄影创建的杨氏条纹图案。条纹间距和方向仅使用一种杨氏条纹图案来确定，无需任何其他衍射晕圈图案。该图像处理系统使我们能够高精度、快速地分析条纹间距和方向或杨氏条纹图案。在由有机玻璃制成的透明紧凑法向和剪切样本上，通过散斑摄影在混合模式加载下测量了近裂纹尖端场的位移。通过位移外推法评估沿裂纹前沿的应力强度因子（SIF）。对相同的样本进行有限元分析。通过比较混合模态问题的虚拟裂纹扩展法和位移法，讨论了SIF的精度。在从自由表面到样品中心的不同平面上讨论了 SIF 随载荷施加角度的变化。从样本的中部到 3mm 的深度，SIF 几乎是均匀的。因此，在试样深度 3mm 处测量 SIF 就足够了。样本中心部分的 SIF 与二维平面应变分析获得的 SIF 有很大不同。通过嵌入式散斑摄影可以高精度测量混合模式加载下均质材料的 SIF。该方法用于测量界面裂纹问题的 SIF。使用钢和环氧树脂作为不同材料。通过散斑摄影测量自由表面处沿裂纹线的位移。在试件自由表面处，散斑摄影获得的SIF与有限元分析获得的SIF一致。界面裂纹的 SIF 也可以通过散斑摄影来评估。

项目成果

Kenji Machida: "Measurement of Stress Intensity Factors of a Mixed-Mode Interface Crack by a Speckle Photography" OPTICAL REVIEW. 4・2. 253-260 (1997)

Kenji Machida：“通过散斑摄影测量混合模式界面裂纹的应力强度因子”光学评论 4・2 (1997)。

Kenji Machida: "Measurement of Stress Intensity Factors of a Mixed-mode Interface Crack by a Speckle Photography" Tech.Digest of 1996 Int.Workshop on Interferometry. 93-94 (1996)

Kenji Machida：“通过散斑摄影测量混合模式界面裂纹的应力强度因子”1996 年干涉测量国际研讨会的技术文摘。

Machida, K: "Stress Singularity Field of a Mixed-mode Three-dimensional Crack by an Embedded Speckle photography" 1996 Vlll International Congress on Experimental Mechanics. 48-49 (1996)

Machida, K：“通过嵌入式散斑摄影研究混合模式三维裂纹的应力奇异场”1996 年第 11 届国际实验力学大会。

町田 賢司: "スペックル法と有限要素法による混合モード界面き裂の応力拡大係数" 日本機械学会論文集. 64A・618. 284-289 (1998)

Kenji Machida：“使用散斑法和有限元法的混合模式界面裂纹的应力强度因子”，日本机械工程学会会刊 64A・618（1998 年）。

Kenji Machida: "stress Singularity Field of a Mixed-mode Three-dimensional Crack by an Embedded Speckle Photography" Abst.Proc,VIII Int,Cong,Exp,Mech.48-49 (1996)

Kenji Machida：“通过嵌入式散斑摄影应力混合模式三维裂纹的奇异场”Abst.Proc，VIII Int，Cong，Exp，Mech.48-49（1996）