Interior Strain Analysis of Red Stone Rock under Compression Using Digital Volumetric Speckle Photography

Abstract

Most stress/strain analysis problems are three-dimensional (3D) in nature. Yet there is scarcely any practical experimental technique that can be employed to tackle the problem with accuracy. The earliest attempts see the development of frozen stress photoelasticity and scattered light photoelasticity. But the need to use a transparent birefringent material to model the real problem severely restricts their applicability. And the complicated procedures render these techniques evenless attractive. Recently, we (Mao and Chiang) developed a 3D stress/strain analysis technique which has the potential to revolutionize the field. We take advantage of true 3D imaging technique such as CT (Computer Tomography) and MRI (Magnetic Resonance Imaging) to record a volumetric image of an object. We extended the 2D digital speckle photography technique developed by Chiang et al. to 3D such that it can be applied to stress/strain analysis of any non-transparent materials. This paper presents the first application of this technique to analyzing the deformation of red sandstone rocks.