| Comparison of a Video Extensometer Over a Clip-On Extensometer and Crosshead Motion as a Strain Measurement Technique for Testing Nitinol Specimens in Tension | ||
| Ms. Meredith Viveiros1 and Z.C. Lin2, 1Instron Corporation, 825 University Avenue, Norwood, MA 02062, 2Guidant Corporation, 3200 Lakeside Drive, Santa Clara, CA 95054
According to the recently issued ASTM standard, F2516-05: Standard Test Method for Tension Testing of Nickel-Titanium Superelastic Materials, strain measurement for nitinol specimens can be determined by machine crosshead motion or an extensometer. A video extensometer is non-contacting extensometer that can measure one-dimensional deformation of a specimen by tracking the movement of two attached markers. Typical Stress-Strain diagrams of Superelastic Nitinol will be compared between three different strain measurement techniques: a video extensometer, a clip-on extensometer and crosshead motion. Gauge length and crosshead speed will be varied per the ASTM F2516. Discussion will address features and limitations of each strain measurement technique. | ||