Measurement of elastic properties of materials employing 3-D DIC in a Cornu’s experiment

Measurement of elastic properties, especially the Poisson’s ratio, utilizing non-contact techniques in a tensile experiment is very challenging. This is primarily due to the poor spatial resolution and the large strain noise inherent to these techniques. The difficulty level increases many folds when Poisson’s ratio of less elongating, stiffer, and/or brittle materials, like ceramics and ablatives, is measured. This paper reports a newer approach that employs 3-D digital image correlation (3-D DIC) in a Cornu’s experiment to enable accurate measurement of elastic properties in a single test. The deflection field obtained from 3-D DIC in the form of anticlastic surfaces during Cornu’s experiment is utilized for determining Poisson’s ratio. In the same experiment, the elastic modulus is estimated using the center point deflection method. The proposed methods are validated with standard materials and extended to newly developed materials. Cornu’s method with 3-D DIC can provide the elastic properties with ease and has many advantages over other conventional techniques.