Materials Science and Engineering Seminar: Deformation Measurement of Materials with Digital Image C
Dr. Louis Hector, General Motors Technical Fellow
Friday, October 5, 2012
4:10 pm – 5:00 pm
Digital image correlation (DIC) is a non-contact technique for full-field strain measurement of materials. The input to the correlation algorithm requires a set of digital images that store the deformation history recorded from one surface of the material as it is strained. Cumulative strain fields are computed by comparing a reference image with an image recorded at a later stage. Alternatively, incremental strain fields are computed by comparing temporally successive image pairs. There is a substantial amount of underlying mathematical machinery associated with DIC. However, in this presentation, we shall “side-step” the mathematics and focus on a “visual display” of deformation processes where two-dimensional DIC has played a role in understanding materials deformation. After a short review of how DIC works, we will launch into an examination of some advanced high strength steels and explore underlying materials science. We will then investigate the Portevin-Le Châtelier effect in steel and aluminum alloys and a custom image acquisition algorithm used to study this intriguing material instability. From there, we will move to cruciform testing of magnesium with a biaxial fixture. The presentation will conclude with a new application for DIC.
Room: 112 Jack E. Brown
Texas A&M University