Wyniki wyszukiwania - BazTech

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Evaluation of the effect of muscle forces implementation on the behavior of a dummy during a head-on collision

Sybilski Kamil, Mazurkiewicz Łukasz, Jurkojć Jacek, Michnik Robert, Małachowski Jerzy

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 4

137--147

EN

Purpose: The aim of this study was to develop a method to implement muscle forces to a numerical model of a dummy and to evaluate the effect of muscle activation on driver behavior during a frontal collision. The authors focused on the forces acting at the knee, hip, and elbow joints. Methods: The authors carried out torque measurements in joints using the Biodex System 4. Then, the previously developed numerical models were modified by introducing the joint torque values. Moments of force were introduced as a function of the rotation angle. During research, numerical simulations were carried out in three stages: in the first stage, a full vehicle crash was analyzed to determine the change of velocity of the vehicle interior; in the second stage, subsidence of the system was realized; in the third stage, a frontal crash was simulated. The models considered the operation of the sensors, airbag and seat belt tensioning system. Results: A numerical model with the active response of the dummy to the change in position during impact was developed. The results of the dynamic analysis were used to analyze the impact of muscle activation on dummy behavior. The change in shoulders rotation angle, the lateral and vertical displacement of the dummy’s center of gravity, and the forces acting between the dummy and the seat belt were compared. Conclusions: The effect of muscle action on the behavior of a dummy during a frontal collision was determined.

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Experimental and numerical flow analysis through arteries with stent using particle image velocimetry and computational fluid dynamics method

Tomaszewski Michal, Sybilski Kamil, Baranowski Pawel, Malachowski Jerzy

Biocybernetics and Biomedical Engineering

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2020

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Vol. 40, no. 2

740--751

EN

In the paper, an experimental and numerical flow through various kind of arteries is considered. The flow analyses are carried out on the research set up using Particle Image Velocimetry Method (PIV). The individual components of the research set up are discussed and the measurement methodology is explained. The work consists of two parts. The first one is focused on modelling numerical simulation of the stent installation procedure using an expandable balloon and the flow domain design methodology is described. In the final part, an experimental flow test on an artificial silicone vessel (diameter 3.2 mm) with a stent is performed. The results of the experimental tests are compared with a corresponding numerical simulation. The paper presents numerical simulation for two different flow domains and the results obtained from the experimental tests. In both, the experimental tests and numerical simulation, the pulsatile time dependent flow and pressure characteristic are used. Hemodynamic parameters such as the time average wall shear stress (TAWSS) and velocity vector distribution are analysed. The flow was studied at four Reynolds number values (1223; 2257; 3198; 3762) for the straight vessel and at two values for the vessel containing a stent (1223, 2257). A diameter of the vessel was 3.2 mm. Pulsating blood flow based on the data from the experimental test was analysed. During the numerical simulation it was verified which regions of the vessel had TAWSS values below 0.4 Pa. A satisfactory correlation between outcomes of the numerical simulation and the experimental test was obtained. The flow analysis is conducted in ANSYS Fluent software. Additionally, the methodology for defining the velocity profile at the entrance is presented, in order to form the velocity profile in the first step of analysed cases. The study shows possibility to create a new research set up capable of testing various clinical cases of varying pressure values in the setup, or testing the effects of vessel geometrical changes, which allows observing an influence of those parameters on the fluid flow characteristic. As the analysis for the stent has shown, the regions of low TAWSS values are located in a close proximity to the stent struts.

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Numerical and experimental analysis of balloon angioplasty impact on flow hemodynamics improvement

Tomaszewski Michał, Sybilski Kamil, Małachowski Jerzy, Wolański Wojciech, Buszman Piotr P.

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 3

169--183

EN

Purpose: The paper focuses on the numerical and experimental evaluation of the fluid flow inside chosen fragments of blood vessels. In the first stage of the study, the experimental tests were conducted using a research test stand, designed to be used in this evaluation. The study evaluated the blood flow through a silicone vessel with an implanted coronary stent. Methods: The PIV method was used in order to visualize the flow vectors inside a silicone vessel. Deformed vessel geometry implemented for computational fluid dynamics purposes was obtained owing to a non-linear simulation of the stent expansion (angioplasty process) in a silicone vessel. Additionally, a vessel model with a statistical 55% area stenosis and an irregular real vessel with an atherosclerotic plaque were also subjected to analysis from the hemodynamic flow point of view. A vessel with a statistical stenosis was also used to simulate the angioplasty process, which resulted in obtaining a flow domain for the vessel with an atherosclerotic plaque after the stent implantation. Results: For each case, distributions of parameters such as OSI or TAWSS were also analyzed and discussed. The areas of low TAWSS values appear close to the stent struts. Conclusions: Stents with increased diameters, compared to the normal vessel diameter, create a higher risk of occurrence of the areas with low WSS values. Excessive stent deformation can cause inflammation by injuring the vessel and can initiate the restenosis and thrombotic phenomena through the increased vessel diameter.

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Finite element head model for the crew injury assessment in a light armoured vehicle

Burkacki Michał, Wolański Wojciech, Suchoń Sławomir, Joszko Kamil, Gzik-Zroska Bożena, Sybilski Kamil, Gzik Marek

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 2

173--183

EN

Purpose: The aim of this paper was the development of a finite element model of the soldier’s head to assess injuries suffered by soldiers during blast under a light armoured vehicle. Methods: The application of a multibody wheeled armoured vehicle model, including the crew and their equipment, aenabled the researchers to analyse the most dangerous scenarios of the head injury. These scenarios have been selected for a detailed analysis using the finite element head model which allowed for the examination of dynamic effects on individual head structures. In this paper, the authors described stages of the development of the anatomical finite element head model. Results: The results of the simulations made it possible to assess parameters determining the head injury of the soldier during the IED explosion. The developed model allows the determination of the parameters of stress, strain and pressure acting on the structures of the human head. Conclusion: In future studies, the model will be used to carry out simulations which will improve the construction of the headgear in order to minimize the possibility of the head injury.

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Rejestracja ruchu żuchwy względem podstawy czaszki

Bukała Jakub, Małachowski Jerzy, Pietroń Kamil, Sybilski Kamil, Szafrańska Aleksandra

Aktualne Problemy Biomechaniki

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2019

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z. 17

11--17

PL

W pracy przedstawiono metodę badawczą pozwalającą na wyznaczenie krzywych opisujących ruch żuchwy względem podstawy czaszki człowieka bazującą na wideo-analizie. Do pomiaru wykorzystuje się markery pasywne odbijające promieniowanie podczerwone, które umieszczane są na nakładkach mocowanych do tkanek twardych osoby badanej.

EN

The study presents a research method for determining movement curves of the human mandible in relation to the base of the skull. The method is based on video analysis of passive markers reflecting IR radiation. Markers are placed on the personalized overlays fastened to the hard tissues of the examined person.