Digital image correlation (DIC) is a video (non-contact) imaging technology for measuring deformations and strains in the testing of mechanical properties of materials. DatapointLabs’ acquired GOM’s ARAMIS 4M60 in April this year, a stereo camera based apparatus for three dimensional visualization of the test specimen as it is being deformed in a testing machine. It is capable of strain measurements in the quasi-static to moderate strain rate ranges and at non-ambient temperatures. Because there is no contact with the test specimen, a wide variety of materials can be accommodated. A key benefit of the technology is virtual strain gauging which gives us the ability to measure localized straining that may occur, for example, at the onset of necking. Such measurements cannot be achieved without DIC, yet constitute an important quantification of how a material fails. The virtual strain gauging capability is also essential in other property measurements such as shear properties of composites, and in the development of forming limit diagrams. Shear properties can be made using conventional strain gauges but DIC allows precise placement of virtual strain gauges in the location of pure shear, greatly advancing the precision of such measurements.
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