Development of the digital image correlation (DIC) method for mechanical testing at elevated temperatures

The results of experimental studies on the evaluation of the performance of the non-contact optical video system Vic-3D and the digital image correlation method during tensile tests of composites under normal and elevated temperatures are presented. The dependences of the recorded strain values are analyzed by two independent measurement methods: the digital image correlation method (DIC) and a mounted extensometer. The tests were carried out at the Center of Experimental Mechanics of the Perm National Research Polytechnic University using the Instron 5882 universal electromechanical testing system, which includes a thermal chamber with an operating temperature range of -100° to +350 °С. Samples of a composite material made of STEF fiberglass and carbon fiber were studied. Tensile tests were carried out at temperatures of 2°2, 100°, 120°, 200°, and 300°C. Recommendations for conducting temperature tests using the DIC method are proposed. Based on the test results, deformation diagrams were constructed. Fields and diagrams of longitudinal deformations are obtained at different temperature levels. A detailed evaluation of the finely dispersed coating required for the implementation of the DIC method in temperature tests has been carried out.