A Biaxial Strain–Based Expansion Mechanism for Auxetic Stent Deployment
| Autor: | Sarim Asif, Umer Mohammad, Hafsah Akhtar, Faiza Bukhari, Umar Ansari, Mariam Mir, Murtaza Najabat Ali |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Fabrication Auxetics medicine.medical_treatment Biomedical Engineering Biophysics Hinge Bioengineering 02 engineering and technology Prosthesis Design Thermal expansion Biomaterials 03 medical and health sciences 0302 clinical medicine Machining Pressure medicine 030212 general & internal medicine Mechanical Phenomena business.industry Work (physics) Balloon catheter Stent General Medicine Structural engineering 021001 nanoscience & nanotechnology Stents 0210 nano-technology business |
| Zdroj: | Journal of Applied Biomaterials & Functional Materials. 15:196-205 |
| ISSN: | 2280-8000 |
| DOI: | 10.5301/jabfm.5000326 |
| Popis: | Background Auxetics, a special class of materials, tend to expand both in the radial and longitudinal directions when a unidirectional tensile force is applied. Recently, studies have come up with new designs for auxetic vascular and nonvascular stents which are deployed with commercial balloon catheters. There are some inherent limitations associated with a unidirectional application of expansion force in the effective deployment of stents. This work proposed a solution to some of these limitations through the use of a biaxial mode of a predetermined strain-based expansion mechanism. Method The design incorporated a pressure-activated crank-slider mechanism. Fabrication of a prototype for experimental verification was carried out through milling and high-speed lathe machining. The testing of the device employed the use of auxetic stents, fabricated from a biocompatible polymer. A finite element study is presented to extrapolate experimental results to a broader range of operation and working conditions. Results and Conclusions The expansion mechanism is similar in operation to the opening of an umbrella. The length of the connected auxetic stent increases when internal hydraulic pressure is applied. The degree of linear expansion in 1 direction influences the expansion of auxetic stent in the lateral direction. As the device exerts pressure longitudinally, a larger amount of the force is distributed on the unit cells/hinges which ultimately results in an increased expansion of the stent. |
| Databáze: | OpenAIRE |
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