Development and Application of Multi-Scale Numerical Tool to Modeling Pneumatic Ventricular Assist Devices with Increased Athrombogenicity

The multi-scale numerical model of blood chamber of ventricular assist device (VAD) with deposited a biocompatible titanium nitride (TiN) nano-coating is introduced. The model is developed to optimize shape parameters of the blood chamber and to determine fracture parameters of the nano-coating. The development of finite element (FE) macro-model is combined with a digital image correlation data to validate a computed strain state. Contrary, on a micro-scale calibration and validation of a representative volume element (RVE) model of the wall of VAD composed of the TiN coating and substrate-polymer is realized by comparison with results of an experimental in situ SEM's micro-tensile test. The multi-scale model of VAD is enriched with materials research. Thus, tensile tests of VADs' polymers are performed to obtain the properties of designed materials of the VADs. On the other hand, on a micro-scale, the properties of TiN are identified based on a nanoindentation test and an inverse analysis for its interpretation. The profilometric studies and analytical model are presented to calculate a residual stress in the TiN. The final result of the paper is the multi-scale numerical tool to modeling pneumatic VADs with increased biocompatibility produced in Poland.