Strain analysis in diametral compression test through digital image correlation

Abstract

Abstract In the search for alternatives to obtain more information from rock tests and to make them more accessible, this study applies the Digital Image Correlation technique (DIC 2D) in a diametral compression test called Brazilian Test, comparing the result measured by an extensometer with the result obtained by DIC. Rock tests provide information about rock characteristics applicable to several engineering areas, such as mining and construction. In tests using strain gauges to measure strain, the equipment is expensive and there is a risk of breaking the instrument due to the contact with the specimen. However, tests measuring strain through the DIC technique may be more accessible, using open source software and lower cost equipment when compared to the cost of the extensometers. The results of this study demonstrate that the DIC technique enables: 1) complementing the information of diametrical tests obtained using strain gauges, for example, supporting the visualization of crack propagation; and 2) in some cases, replacing the use of extensometers, as far as a variation is tolerated.

Keywords

• Digital Image Correlation
• rock mechanics
• extensometer