Wyniki wyszukiwania - BazTech

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Numerical analysis of stent expansion process in coronary artery stenosis with the use of non-compliant balloon

Bukala J., Kwiatkowski P., Malachowski J.

Biocybernetics and Biomedical Engineering

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2016

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Vol. 36, no. 1

145--156

EN

In the paper the authors present an applied methodology, data and numerical results for numerical analysis of the stent crimping process and stent implantation in the coronary artery stenosis with the use of a non-compliant angioplasty balloon. The authors focused on the modeling methodology of balloon angioplasty with minimum possible simplification, i.e.: a full load path (compression and inflation in single analysis), 3D unsymmetrical geometry and discretization, highly nonlinear material models (hyperelasticity, plastic kinematic formulation, crushable foam) and sophisticated contact models (bodies with highly different stiffness). The use of a highly compressible crushable foam material model for an arterial plaque is considered as the most original part of the work. The presented results allow for better understanding of the mechanisms governing stent crimping and implementation.

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LS-Dyna contact procedure analysis for selected mechanical systems

Małachowski J., Bukala J., Damaziak K., Tomaszewski M.

Journal of KONES

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2015

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Vol. 22, No. 1

193--202

EN

Finite Element Method is one of the most frequently used computational schemes in numerical analyses. A contact phenomenon is an essential issue when modelling the physical interaction between two or more bodies. Depending on the used software, the various contact algorithms are applied. In the paper, the authors present the results of evaluation of different contact methods implemented in LS-Dyna CAE software. The most common problem arising during contact modelling is the occurrence of penetration between the coupling elements, which leads to an increase of contact forces and, consequently, a local deformation of finite elements. In the introduction, a theoretical background related to mathematical aspects of contact modelling is presented, in particular search methods for contact surfaces and the penalty forces calculating method. Subsequently, a contact analysis for different variants of interaction of the elements is presented. In the first analysed case, shaft- sleeve interaction, in both rotation and translation, is presented. The variable factors in this case were a number of interacting finite elements and the type of a contact algorithm. The second case focused on the interaction forces resulting from the interaction between two sliding bodies in the harmonic motion. A sliding body was pressed against the plane using an increasing force. A variable factor in this case was the type of the implemented contact algorithm.

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A comparative analysis of popular modern small wind turbine design solutions in terms of estimated cost to power output ratio

Bukala J., Damaziak K., Kroszczyński K., Krzeszowiec M., Malachowski J.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2014

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nr 146

57--68

EN

In this paper a series of estimations has been performed in order to establish the actual cost-effectiveness of small wind turbines (SWTs). Different design solutions have been evaluated and based on their power curves and installation costs, using accurate wind data, a rate of investment return (ROI) period has been calculated for each one of them. The chosen turbines are: a classic three bladed horizontal axis wind turbine (HAWT), an advanced diffuser augmented HAWT and a Darrieus type vertical axis wind turbine (VAWT). The conclusions drawn from this study entertain the idea that from the economical point of view, a price reduction of SWT systems is more important, than aerodynamic complexity and efficiency.