Mechanical testing of stents involves a range of different tests that encompass both static and fatigue methods. Stents are most commonly made from Nitinol wire, which must be tested to ASTM F2516 in a simple cyclic test. Another static test that is often carried out on stents is a flexural test in accordance with ASTM F2606. In addition to testing the raw material, the diamond structure of the stent body is commonly tested in fatigue at 60 Hz in position control. The entire stent body is also typically tested in radial compression as a static test, and pulsatile fatigue or cyclic fatigue as a dynamic test. Considering that such a variety of mechanical tests are required on any single stent, it is often challenging to select the appropriate test system for conducting as many tests as possible.
For all static testing, including testing to ASTM 2516, ASTM F2606, and radial compression testing on the full stent body, we recommend using a 5940 Series or 5960 Series system. When testing Nitinol Wire to ASTM 2516, we recommend utilizing our Advanced Video Extensometer for accurate strain measurement. When testing full stent bodies in radial compression, Instron® partners with Machine Solutions Inc. (MSI) to provide a specialized fixture. The radial compression fixture can be mounted to any Instron 5940 or 5960 series system and can utilize standard Bluehill® Universal software to control the test. For all fatigue tests, including testing the diamond structure of the stent body or the entire stent in cyclic extension control, we recommend using our ElectroPuls™ test systems.