Search results for "Nitinol"
showing 5 items of 5 documents
Unconventional application of Image Correlation techniques on Biomaterials and cardiovascular applications
2022
Image Correlation techniques are increasing in popularity and are now suitable to investigate complex structural and fluid-dynamics of cardiovascular systems. These approaches operate through a digital correlation of a pair of images to determine physical quantities of complex systems. In this thesis, their application to the mechanical characterisation of complex biomaterials (Nitinol and soft materials), and the characterisation of complex biofluid-dynamics was investigated, with the aim to analyse their reliability and enhance their accuracy and field of application. Digital Image Correlation, supported by Infrared Thermography, was used to achieve a more in depth understanding of the me…
Multi-objective optimization of nitinol stent design.
2017
Nitinol stents continuously experience loadings due to pulsatile pressure, thus a given stent design should possess an adequate fatigue strength and, at the same time, it should guarantee a sufficient vessel scaffolding. The present study proposes an optimization framework aiming at increasing the fatigue life reducing the maximum strut strain along the structure through a local modification of the strut profile.The adopted computational framework relies on nonlinear structural finite element analysis combined with a Multi Objective Genetic Algorithm, based on Kriging response surfaces. In particular, such an approach is used to investigate the design optimization of planar stent cell.The r…
Influence of the type of reciprocating motion on the cyclic fatigue resistance of reciprocating files in a dynamic model
2021
Abstract Background The aim of this study was to compare the influence of two novel reciprocating movements on the cyclic fatigue resistance of endodontic reciprocating files. Methods 30 Procodile® (Komet Medical, Lemgo, Germany) files were selected in this study and distributed according to the following study groups depending on the movements to be performed: ReFlex Dynamic (n = 10), ReFlex Smart (n = 10) and Reciproc (n = 10) reciprocating movement. These files were fixed to a specific dynamic cyclic fatigue device designed and manufactured by 3D impression to simulate the pecking motion performed by the operator. The time to failure and the number of cycles of in-and-out of the endodont…
Nitinola matricas ar bioaktīvo slāni izveide pielietojumam asinsvadu ķirurģijā
2022
Darba mērķis bija izpētīt Nitinola matricas ar bioaktīvo slāni biosaderību un izvērtēt tās priekšrocības salīdzinājumā ar Nitinolu. Lai sasniegtu mērķus, tika veikta izpēte un apkopoti aktuālie zinātniskie dati par Nitinola pielietošanu asinsvadu ķirurģijā, plazmas elektrolītiskās oksidācijas Nitinola izveidi un biosaderību, nanodimantu biosaderību. Tika veikta Nitinola plazmas elektrolītiskā oksidēšana un iegūto biomateriālu raksturošana ar skenējošo elektronu mikroskopa metodi. Tika apstrādāti nitinola ar bioaktīvo nanodimantu pārklājumi un veikta to raksturošana ar fizikālām metodēm. Eksperimentāli tika izpētīta Nitinola matricas ar bioaktīvo nanodimantu slāņu biosaderība ar cilvēka fibr…
Investigation of the Thermomechanical Response of Cyclically Loaded NiTi Alloys by Means of Temperature Frequency Domain Analyses
2021
Nickel–Titanium (NiTi) shape memory alloys subjected to cyclic loading exhibit reversible temperature changes whose modulation is correlated with the applied load. This reveals the presence of reversible thermomechanical heat sources activated by the applied stresses. One such source is the elastocaloric effect, accounting for the latent heat of Austenite–Martensite phase transformation. It is, however, observed that when the amplitude of cyclic loads is not sufficient to activate or further propagate this phase transformation, the material still exhibits a strong cyclic temperature modulation. The present work investigates the thermomechanical behaviour of NiTi under such low-amplitude cyc…