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Radial force behavior is one of many engineering design criteria important to the design of implantable medical devices such as stents. Interpretation and extrapolation of bench-top data to predict in-vivo performance necessitates a thorough understanding of influence parameters such as boundary conditions and material uncertainty. An integrated modeling and test validation approach is needed to [...] Phase shifted moire interferometry of crack and transformation zone in Nitinol fatigue specimen. You can download our presentation of Nitinol fatigue and fracture initiation using phase shifted moire interferometry. You can download the brochure for this special symposium that brings together state-of-the-art developments in clinical imaging techniques, computer modeling, medical device testing and materials characterization with a focus on medical implants, their design and the Experimental Mechanics underlying device interaction with the human body. Phase shifted moiré interferometry is used to measure full-field strain during uniaxial tension and four point bend loading of nitinol test samples. Differences between global and full field measurements reveal the effects of localized transformation behavior. Results for two heat treatments of commercially available superelastic Nitinol are presented for tests conducted under controlled temperature conditions. [...] At the 2006 SMST Conference in Asilomar Dr. Paul and I had he privilege of sharing our experience of working with Nitinol and particularly FEA of Nitinol during a full day tutorial. It was an honor to have an hour to discuss the ins and outs of modeling Nitinol using FEA. You can download our [...] You can download a presentation of emerging transcatheter devices and technologies that I put together from the engineering design perspective that includes AAA solutions, fenestrated grafts, embolic protection devices, vena cava filters, stents, closure devices coronary sinus devices and percutaneous heart valves and repair technologies. The transformation behavior of Nitinol under uniaxial tension and four-point bending was investigated. A novel sample geometry produced from drawn tubing was used to observe the differences caused by localized phase transformation effects between the two types of loading and between samples with different process and load histories. Phase shifted moiré interferometry was used to [...]
Nitinol is well suited to the design constraints imposed by medical device applications, however, only modest progress has so far been made regarding long term predictions of the structural integrity of such components. Challenges in predicting long term reliability of superelastic NiTi medical components include the consequences of manufacturing tolerances, uncertainty with regard to in vivo [...] A series of phase shifted moiré interferograms showing a NiTi dogbone experiencing increased tensile loading. The two images on the right exhibit clear Luders bands. You can download our brief paper describing our use of moire interferometry to measure properties of superelastic Nitinol for the reliability assessment of medical devices. The 6F LifeStent NT is an implantable self-expanding nickel titanium alloy (Nitinol) stent. The stent is manufactured from small diameter Nitinol tubing and is loaded into a delivery catheter for placement/deployment into a vessel. The stent is based on a helical design which offers a wide range of performance advantages when compared to stents with circumferential [...] |
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