@ARTICLE{Kopernik_M._Failure_2015, author={Kopernik, M.}, number={No 1 March}, journal={Archives of Metallurgy and Materials}, howpublished={online}, year={2015}, publisher={Institute of Metallurgy and Materials Science of Polish Academy of Sciences}, publisher={Committee of Materials Engineering and Metallurgy of Polish Academy of Sciences}, abstract={AbstractThe Polish ventricular assist device is made of Bionate II with deposited TiN biocompatible nano-coating. The two scale finite element model is composed of a macro-model of blood chamber and a micro-model of the TiN/Bionate II. The numerical analysis of stress and strain states confirmed the possibility of fracture. Therefore, the identification of a fracture parameter considered as a failure strain is the purpose of the present work. The tensile test in a micro chamber of the SEM was performed to calibrate the fracture parameter of the material system TiN/Bionate II. The failure strain is a function of a temperature, a thickness of coating and parameters of surface's profile. The failure strain was calculated at the stage of the test, in which the initiation of fracture occurred. The finite element micro-model includes the surface roughness and the failure strain under tension condition for two thicknesses of coatings which will be deposited on the medical device.}, title={Failure Strain and Strain-Stress Analysis in Titanium Nitride Coatings Deposited on Religa Heart Ext Ventricular Assist Device}, URL={http://www.czasopisma.pan.pl/Content/89436/PDF/10172%20Volume%2060%20Issue%201-19%20paper.pdf.pdf}, doi={10.1515/amm-2015-0020}, }