Stress-separation techniques in photoelasticity: A review

Abstract

Photoelasticity has been used for decades in the experimental measurement of stresses and strains. As data-acquisition techniques only identify the differences between principal stresses and strains, stress-separation techniques exist to identify each of their values separately. A variety of techniques have been developed since the early days of photoelasticity, aiming to automate the measurement process, to exploit the full potential of photoelastic methods, and to facilitate its application. The purpose of this paper is to provide a general overview of the different stress-separation techniques, and their current state of development and usage. The paper presents the publications and the authors who have contributed to the development of new techniques.

Photoelastic‐numerical treatment of Beltrami‐Michell boundary value problems

“…This study has led to an analysis of the plane stress state prevailing in a thin annular subjected to pressure on two diametrically opposite segments of the rim. Besides, it is interesting to note that in both papers [1,2]; an exhaustive bibliographic study has been led to support the investigations. While the concern of our paper aims to show that another method exists, enhancing those related in paper [1].…”

“…Besides, it is interesting to note that in both papers [1,2]; an exhaustive bibliographic study has been led to support the investigations. While the concern of our paper aims to show that another method exists, enhancing those related in paper [1]. In fact, for evaluating the stress state acting in a thin ring subject to a diametral compression, we process swiftly and differently to obtain results, unlike [2].…”

“…Accordingly, two recent papers have drawn our attention with much interest. The one edited by Fernández et al [1], which relates a general review of the different stress-separation techniques in photoelasticity and their current state of development. The paper depicts a list of many publications and authors who have contributed to develop such separation techniques too.…”

Numerical-experimental hybrid method for stress separation in digital gradient sensing method

“…Photoelasticity measures principal stress difference and the principal direction, and thus the stress components themselves cannot be obtained directly. Several methods have been proposed for stress separation in photoelasticity such as the shear difference method [14,15]; numerical analysis of the compatibility equation; oblique incidence and hybrid methods of photoelasticity and another experimental method [16][17][18][19]. However all the above methods for stress separation in photoelasticity are not suitable for that in the DGS method.…”

Full-field stress analysis by holographic phase-stepping implementation of the photoelastic-coating method

“…A holographic phase-shifting realization of the photolastic-coating method [1-3] is an effective approach to separate the stress components over the tested specimen due to its easier and faster implementation in comparison with the oblique-incidence method, the strip coating method and the strain gage separation method [4][5]. For the purpose, a series of six photoelastic fringe patterns (FPs) are recorded at preliminary known orientations of the polarization elements in a circular polariscope to build both isochromatic and isoclinic phase maps which give the loci of points with a constant difference of the principal stresses and a constant principal stress direction respectively.…”