USE OF 2D DIGITAL IMAGE CORRELATION TO FIND POISSON'S RATIO FOR CARBON FIBER REINFORCED EPOXY COMPOSITES

摘要

Strain under load as well and the Poisson's ratio is critical to the understanding of mechanical properties of materials, but is often difficult to measure. In composites, we should know these properties for both the textile reinforcing material, and the finished composite. The attachment of strain gages or a one dimensional (line) camera have proved useful in determining strain in one direction, typically the test direction in tensile testing of materials. Beginning in the early 1980's, a photographic/video technique known as Digital Image Correlation, or DIC, has been available to measure the deformation in two dimensions simultaneously. We have developed a system using off the shelf hardware components and freeware subroutines in MATLABTM to accomplish DIC measurements for strain and Poisson's ratio on carbon epoxy composites. This effort is illustrated by application of DIC to a carbon fiber reinforced composite material during a tensile test. The difficulties encountered and the results of our testing are reported.