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电子散斑干涉和Video全息干涉 总被引:7,自引:2,他引:7
本文综述了有关电子散斑干涉法(ESPI)和Vidco全息干涉技术的一些近期成果.主要包括:有机玻璃模型中主应力和的测量,二维气体温度场和轴对称气体温度场的测量,三维物体表面形状和三维位移场的测量.条纹图均用数字图象处理系统处理.文中介绍了各种测量光路和操作技术,分析了可能出现的误差,提供了部分实验结果. 相似文献
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提出了用超声散斑干涉法来测量物体的位移,并且基于数字干涉和相移-频移技术对超
声散斑数字干涉测量法进行了初步的理论推导. 为了验证理论分析的结果,对一铝试件进行
了离面位移和面内位移的试验测量. 试验结果显示理论分析是正确的,在测量位移和变形时
此方法是有效可行的. 相似文献
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本文提出偏振相移干涉栅投影技术并成功地用于三维物面形状和大变形物体的位移测量,得到较为满意的实验结果。 相似文献
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本文用统计光学方法对双参考光全息——散斑干涉术进行了详尽的理论分析,给出了全息和散斑干涉场区域平均光强分布与光学系统主要参数及三维变形场各分量之间关系的解析表达式,进而讨论了离面位移和面内位移测量的上、下限,最后还给出了有关的实验结果。 相似文献
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本文对N.Abramson提出的夹片方法作了进一步改进。提出了测量物体表面三维变形的双参考光像全息散斑夹片新方法。该法能消除物体由于刚体位移而产生的不良影响。并能有效地消除参考光对测量散斑干涉时出现的严重噪音。文中通过对悬臂梁和玻璃钢三点弯断裂试件的测量及分析,证明了提出的方法是可行的。 相似文献
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本文采用数字散斑干涉法和栅线投影法同时测量了任意曲表面的三维位移和三维形貌,并运用数字图像处理技术分析了曲表面的三维应变场,用实验方法获得了曲表面的主应变和主方向。 相似文献
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Optical full-field measurement methods are now widely applied in various domains. In general, the displacement fields can be directly obtained from the measurement, however in mechanical analysis strain fields are preferred. To extract strain fields from noisy displacement fields is always a challenging topic. In this study, a finite element method for smoothing displacement fields and calculating strain fields is proposed. An experimental test case on a holed aluminum specimen under tension is applied to validate this method. The heterogeneous displacement fields are measured by digital image correlation (DIC). By this proposed method, the result shows that the measuring noise on experimental displacement fields can be successfully removed, and strain fields can be reconstructed in the arbitrary area. 相似文献
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This paper is concerned with small strain measurement utilizing the numerical processing of digital images. The proposed method
has its theoretical basis in digital signal analysis and, from a methodological point of view, it can be considered as an
extension to digital images of the wellknown white light speckle photography technique. That conventional method is based
on the analysis of photographic plates that are exposed twice (before and after the specimen deformation) with the image of
a random speckle pattern that has been previously printed on the test piece surface. The digital speckle correlation advantages
consist of requiring a very simple specimen preparation and, mainly, of allowing the strain field computation just by numerical
elaboration of the acquired images.
In this paper, the theoretical basis of the technique and some valuable improvements to the known analogous methodologies
are presented. Finally, test results for an application of digital speckle correlation are shown and advantages and disadvantages
of the technique are elaborated. In addition, further developments in this area are discussed. 相似文献
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Robert H. Marion 《Experimental Mechanics》1978,18(4):134-140
A new technique for measuring strain at temperatures from room temperature to at least 3000 K has been developed and evaluated. The system was developed for measuring strain during studies of the short-time (seconds to minutes), high-temperature mechanical properties of materials heated by self resistance, but it has general applicability. The technique consists of optically tracking two small ceramiccement targets on the specimen with a digital line scan camera. The targets are illuminated with a laser and viewed through a narrow-band (1-nm) interference filter which eliminates specimen thermal radiation. Experimental testing of the system has been performed on stainless steel and graphite at temperatures up to 1477 K and 3000 K, respectively. With the present lens arrangement, the strain measurement system has a maximum displacement range of 4.24 mm and an overall inaccuracy at temperature of ±4.14 μm. The unique features of this system are: (1) the sensitivity to variations in light level in the tracking range has been substantially reduced; (2) the system is dynamic in that it can operate during heatup and on short-time scales; (3) the nodules are stable and have no adverse effects on the test results; and (4) the system is reliable and easy to use. 相似文献
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数字图像相关方法作为一种新的非接触式位移测量方法,在力学工程中有广泛的应用前景,然而受限于标准方法对图像变形的连续性要求,这种高效的测量方法在断裂力学领域的推广受到了限制. 为解决这一问题,提出采用引入子区分离数学模型,代替标准方法的连续模型,来对非连续区域进行精确识别和匹配的非连续数字图像相关方法. 研究子区被裂纹等非连续分割后原始像素点的位移情况,并引入裂纹张开向量用以表征被分割子区的主区和副区的位移关系;从而建立子区分离模型的数学表达式,并且为所提出的模型设计相应的图像相关算法;然后将所提出的非连续数字图像相关方法应用于重构平板拉伸试验开裂过程中图像的位移. 研究结果表明,相比于标准的数字图像相关方法,所提出的非连续数字图像相关方法解决了图像相关法在非连续区域失效的问题,提高了数字图像相关方法对位移测量的正确率,特别是能够准确重构裂纹面及附近的位移场,其测量精度能够达到亚像素级别. 相似文献