Application of the Digital Image Correlation and the Strain Gauge Method for Determination of the Test Sample Material Properties

The paper deals with the determination of the basic material properties of test specimens subjected to a standard static tensile test. To evaluate surface deformations in the specimens, the non-contact optical method and direct measurement technique based on standard strain gauge methods were used. Nowadays was lot of effective computational correlation algorithms are developed to estimate the whole displacement field in various applications. Digital image correlation algorithm, implemented in open source software, have been used to estimate the displacements and the corresponding strains in field of interest. The set of images which capture track of the material points of the test samples were obtained by a standard camera. The results of strains obtained by the optical method were verified by experimental measurements using an installed uniaxial strain gauge and reference extensometer. The good agreement between the results obtained experimentally using optical and standard strain gauge measurement methods was found. Basic material parameter (Young´s elasticity modulus) was calculated consequently from obtained strain fields. The presented non-contact optical deformation measurement procedure provides a simple and low-cost tool suitable in the teaching process but also research purposes.