Thursday, February 2, 2012
Mechanical and Civil Engineering Semianr
Digital Image Correlation A Revolution in Experimental Mechanics
Phillip Reu, Sandia Laboratories
Digital image correlation (DIC) is a full-field photometric measurement technique that uses two (or more) digital cameras to measure shape, displacement, and strain. This is accomplished by triangulating many uniquely correlated points from the two calibrated cameras of the DIC system. Displacement and strain are measured by tracking these points as the sample is loaded. The full-field nature of the technique allows many thousands of measurement points to be acquired simultaneously, and creates many virtual strain gages spread across the entire sample. This dense measurement set can then be exploited for determining material properties or for other engineering analysis. One of the reasons for the explosive growth in DIC is the revolution in digital imaging including cheap high-resolution digital cameras and high speed imaging systems. This presentation will cover a wide range of Sandia DIC experiments to give a flavor for how DIC can be applied. As with all experiments, under- standing the experimental uncertainties is critical and is a particularly difficult problem for DIC. I will present the current state of DIC uncertainty quantification and the research being done at Sandia in this area.
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energys National Nuclear Security Administration under contract No. DE-AC04-94AL85000.