Strain-rate measurements by electronic speckle-pattern interferometry (ESPI)

We have monitored the evolution of the strain-rates induced on an aluminium sample subjected to a uniaxial tensile test. At different load stages of the test, the strain-rate at each point of the field was obtained from fringe patterns generated by electronic speckle-pattern interferometry (ESPI), a high-sensitivity optical technique. By analyzing these strain-rate fields, we were able to appreciate the trends that characterized the different stages of the test as well as to realize spatial variation in the strain-rate fields linked with the plastic activity progression. We conclude that the strain-rate fields can be efficiently evaluated by using. ESPI.