K. Pike, Abbott Vascular Inc., Santa Clara, CA; B. T. Berg, Boston Scientific Corporation, Maple Grove, MN; P. Adler, Medtronic Cardiovascular, Santa Rosa, CA
A new wire test specimen was developed as part of the Safe Technology consortium project to produce a nitinol algorithm for the fe-safetm fatigue postprocessor. The requirements for the design were; permit tensile and compressive loading, accommodate data collection of strains from ± .1% to 6% at high frequency cycling. The requirements for the wire were; inexpensive, stable, consistent, and commercially available. The requirements for the processing were; incorporate deformation and multiple anneal cycles to simulate manufacturing methods associated with vascular stent production. The final design was a .020 (.508mm) diameter wire formed in a two stage process to produce a Z shaped specimen. The final part met all requirements for testing. Subsequently a second specimen, Z3, and a straight wire specimen were produced to supply additional data to the consortium.
Summary: Development of a simple, low cost tensile and compression fatigue specimen for nitinol devices that undergo multiple annealling steps.
