F. Zhou, M. H. Wu, Edwards Lifesciences, Irvine, CA; X. Y. Gong, Medical Implant Mechanics LLC, Aliso Viejo, CA; S. Zhang, ev3 Endovascular Inc, Plymouth, MN
Superelastic Nitinol tubing has been widely used in various medical applications owing to the modern laser cutting technology to form smaller delivery profile devices and its excellent bio-compatibility. Despite it is well known that Nitinol exhibits a highly asymmetrical tension-compression deformation (a texture effects from the tubing drawing processes), there are very rare published data reporting the compressive mechanical properties of Nitinol tubing. The lack of compression data is due to the difficulties in performing the compression tests on small diameter and thin-walled Nitinol tubing. Therefore, alternative, predictive method is sought from this study. The mechanical properties of superelastic Nitinol tubing were measured by means of uniaxial tension, uniaxial compression, and bend tests to set up the validation for three predictive methods: 1. to derive the compressive transformational strain and stress from tensile and texture measurement, 2. to theoretically deduce the compressive stress-strain relation from a combination of uniaxial tension and bend test results, and 3. to numerically deduce the compressive stress-strain relation by means of finite element analysis. Comparisons of the predictive results and test data are reported.
Summary: The mechanical properties of superelastic Nitinol tubing were measured by means of uniaxial tension, uniaxial compression, and bend tests to set up the validation for three predictive methods: 1. to derive the compressive transformational strain from texture measurement, 2. to theoretically deduce the compressive stress-strain relation from a combination of uniaxial tension and bend test results, and 3. to numerically deduce the compressive stress-strain relation by means of finite element analysis. Comparisons of the predictive results and test data are reported.
