Development of interior strain measurement techniques using random speckle patterns

Abstract

Experimental stress analysis is a well established mechanics discipline dealing with measuring stress/strain in solids under load. Most techniques can only be applied to measuring strain of the surface. In this paper we review the development of techniques of using a random speckle patterns as a quantitative tool to mapping interior strain field of solids. After some elementary treatment of the basic principles of the speckle photography technique we describe three approaches that can probe the interior strain field of a transparent object. They are followed by a newly developed 3D strain measurement technique called digital volumetric speckle photography which can probe the interior of opaque materials as well.

Full-field mapping of internal strain distribution in red sandstone specimen under compression using digital volumetric speckle photography and X-ray computed tomography

“…Digital volumetric speckle photography (DVSP) is another 3D strain analysis technique, which is the extension of 2D digital speckle photography (DSP) technique that offers some advantages over the DVC technique in the computational efficiency. Details of the evolution of the speckle technique leading to the development of DVSP can be found in Chiang and Mao (2015).…”

Three‐dimensional static optical coherence elastography based on inverse compositional Gauss‐Newton digital volume correlation

“…The matching is to fit a target (deformed) subvolume to a reference (un‐deformed) subvolume through changing the position and the shape of the target subvolume. Efforts have been put on improving the speed of calculation with gradient method , Newton‐Raphson (NR) method , and Gauss‐Newton (GN) method . Lately, Pan et al proposed a 3D inverse compositional Gauss‐Newton (IC‐GN) method, which had the ability of noise resistance and high speed due to the Hessian matrix calculation avoidance at each iteration.…”

3D Strain Mapping of Opaque Materials Using an Improved Digital Volumetric Speckle Photography Technique with X-Ray Microtomography

“…As an extension of the 2D DSP (Digital Speckle Photography) method [5,6], we have developed a 3D interior full field deformation measurement technique called digital volumetric speckle photography (DVSP) with the help of X-ray microtomography [32]. This technique has been successfully applied to mapping the internal 3D strain fields of rocks [33][34][35], concrete [36], and composites [37][38][39].…”