Anthony Nicholas, Cadenazzi Guido, Kirkwood Henry, Huwald Eric, Nugent Keith, Abbey Brian
ARC Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
Sci Rep. 2016 Aug 4;6:30541. doi: 10.1038/srep30541.
The elastic properties of materials, either under external load or in a relaxed state, influence their mechanical behaviour. Conventional optical approaches based on techniques such as photoelasticity or thermoelasticity can be used for full-field analysis of the stress distribution within a specimen. The circular polariscope in combination with holographic photoelasticity allows the sum and difference of principal stress components to be determined by exploiting the temporary birefringent properties of materials under load. Phase stepping and interferometric techniques have been proposed as a method for separating the in-plane stress components in two-dimensional photoelasticity experiments. In this paper we describe and demonstrate an alternative approach based on photoelastic ptychography which is able to obtain quantitative stress information from far fewer measurements than is required for interferometric based approaches. The complex light intensity equations based on Jones calculus for this setup are derived. We then apply this approach to the problem of a disc under diametrical compression. The experimental results are validated against the analytical solution derived by Hertz for the theoretical displacement fields for an elastic disc subject to point loading.
材料的弹性特性，无论是在外部载荷作用下还是处于松弛状态，都会影响其力学行为。基于光弹性或热弹性等技术的传统光学方法可用于对试样内应力分布进行全场分析。圆偏振光镜与全息光弹性相结合，通过利用材料在载荷作用下的临时双折射特性，可以确定主应力分量的和与差。相移和干涉测量技术已被提出作为在二维光弹性实验中分离面内应力分量的一种方法。在本文中，我们描述并演示了一种基于光弹性叠层成像的替代方法，该方法能够从比基于干涉测量的方法所需的测量次数少得多的测量中获得定量应力信息。推导了基于琼斯算法的该装置的复光强方程。然后我们将这种方法应用于圆盘在直径压缩下的问题。实验结果与赫兹推导的弹性圆盘在点载荷作用下理论位移场的解析解进行了验证。
