Woolard D, Hinders M
Appl Opt. 2000 May 1;39(13):2043-53. doi: 10.1364/ao.39.002043.
In any automated algorithm for interpreting photoelastic fringe patterns it is necessary to understand and quantify sources of error in the measurement system. We have been considering how the various components of the coating affect the photoelastic measurement, because this source of error has received fairly little attention in the literature. Because the reflective backing is not a perfect retroreflector, it does not preserve the polarization of light and thereby introduces noise into the measurement that depends on the angle of obliqueness and roughness of the reflective surface. This is of particular concern in resolving the stress tensor through the combination of thermoelasticity and photoelasticity where the components are sensitive to errors in the principal angle and difference of the principal stresses. We have developed a physical model that accounts for this and other sources of measurement error to be introduced in a systematic way so that the individual effects on the fringe patterns can be quantified. Simulations show altered photoelastic fringes when backing roughness and oblique incident angles are incorporated into the model.
在任何用于解释光弹性条纹图案的自动算法中，有必要了解并量化测量系统中的误差来源。我们一直在思考涂层的各个组成部分如何影响光弹性测量，因为这一误差来源在文献中受到的关注相当少。由于反射背衬并非完美的后向反射器，它不能保持光的偏振，从而将取决于反射表面倾斜角度和粗糙度的噪声引入测量中。在通过热弹性和光弹性的结合来解析应力张量时，这一点尤为重要，因为其中的分量对主角度和主应力差的误差很敏感。我们已经开发了一个物理模型，该模型考虑了这一因素以及其他测量误差来源，并以系统的方式引入这些误差，以便能够量化它们对条纹图案的各自影响。模拟结果表明，当将背衬粗糙度和斜入射角纳入模型时，光弹性条纹会发生变化。
