DEVELOPMENT OF TENSOR FIELD CT-METHOD FOR HYBRID TECHNIQUE IN STRESS AND STRAIN ANALYSES

本研究的主要目的是克服旋光技术中消除偏振轴沿入射光路旋转的三个参数难以精确测量的困难，建立一种适用于对称应力场和非对称应力场的二维和三维光弹性应力应变分析方法。(1)Jone的矩阵傅里叶图像偏振测量技术：截至上个财政年度末，利用1998年的助学金建立了偏振测量技术的硬件系统。然后，将二维场技术成功地应用于径向压缩下薄圆盘和厚圆盘的延迟角、方位角和椭圆角的精确测量和确定。为了确定三维球体模型中的二次主应力场，现已发展了双光束入射技术。虽然还需要进一步改进，但…三色激光散射光弹性技术：另一种高期望的三维分析方法是以三色激光为光源的散射光技术的改进，用单色光取代了现有的技术。在这项研究中，不仅成功地分析了球体在径向压缩作用下的次主应力差和方位角，而且成功地分析了应力分布的对称面和非对称面。方位角测量精度的进一步提高仍然存在，但该技术被证明是非常有用的。(3)椭圆偏振白光的光弹性和光粘弹性技术：在目前的光(粘弹性)技术中，必须获得两种以上不同的光学信息。这意味着不可能跟踪应力场的时间变化，特别是在运动状态下的裂纹尖端和/或接触区的情况下。该技术利用椭圆偏振白光，一次曝光即可同时测量等色线和等斜线。成功地展示了该技术在计算裂纹尖端应力场中的几个应用。较少

The main purposes of this study are how to overcome difficulties in accurate and precise measurement of three parameters in the polarimetry technique eliminating the rotation of polarization axis along the path of incident light, and to establish a useful method for 2D and 3D photoelastic stress and strain analysis not only in symmetrical but in unsymmetrical stress fields. The results are summarized as follows ;(1) Jone's Matrix Fourier Image Polarimetry Technique : Till the end of last fiscal year, the hardware system for the polarimetry technique has been established utilizing the grant-in-aid in 1998. Then, the technique for 2D fields is successfully applied to the accurate measurement and determination of retardation, azimuth and ellipticity angles both in thin and thick disks under diametrical compression. In order to determine the secondary principal stress field in a 3D sphere model, double beam incident technique is now developed. Although some further improvements are needed, … More the fundamental algorithms and techniques are completed.(2) Scattered Light Photoelasticity Technique with Tricolor Laser : Another approach to 3D analysis with high expectation is the improvement of the scattered light technique using a tricolor laser for light source sloughing off the current technique with a monochromatic light. In this study, secondary principal stress difference and azimuth angle in a sphere under diametrical compression is successfully analyzed not only in symmetrical but unsymmetrical planes of stress distribution. Further improvement in accuracy of azimuth measurement is still exist, but the technique is proven to be very useful.(3) Photoelastic and Photoviscoelastic Techniques with Elliptically Polarized White Light : In the current photo (visco) elastic technique, more than two different optical information have to be obtained. The fact means that it has been impossible to trace the time variation of stress field, particularly in cases of crack tip and/or contact regions under moving condition. The technique proposed enables simultaneous measurement both of isochromatics and isoclinics with a single exposure, using elliptically polarized white light. Several applications of the technique to the evaluation of crack tip stress field is successfully demonstrated. Less