Comparison of infrared and 3D digital image correlation techniques applied for mechanical testing of materials

• IR thermography strain visualization method was evaluated and compared with 3D digital image correlation.
• Tension and tree point bending tests of aluminum alloys have been performed with several loading velocities.
• Limits and capabilities of both methods have been evaluated.
• Results represent prove of IR thermography when used for evaluating complex structures, e.g. metal foams.
• Three point bending test is found to be more appropriate for comparing numerical model than tension test.

To investigate the applicability of infrared thermography as a tool for acquiring dynamic yielding in metals, a comparison of infrared thermography with three dimensional digital image correlation has been made. Dynamical tension tests and three point bending tests of aluminum alloys have been performed to evaluate results obtained by IR thermography in order to detect capabilities and limits for these two methods. Both approaches detect pastification zone migrations during the yielding process. The results of the tension test and three point bending test proved the validity of the IR approach as a method for evaluating the dynamic yielding process when used on complex structures such as cellular porous materials. The stability of the yielding process in the three point bending test, as contrary to the fluctuation of the plastification front in the tension test, is of great importance for the validation of numerical constitutive models. The research proved strong performance, robustness and reliability of the IR approach when used to evaluate yielding during dynamic loading processes, while the 3D DIC method proved to be superior in the low velocity loading regimes. This research based on two basic tests, proved the conclusions and suggestions presented in our previous research on porous materials where middle wave infrared thermography was applied.