Biomechanics / Biomechanical Engineering
Nima Sarrafzadeh Ghadimi; Farzan Ghalichi; Hanieh Niroomand-Oscuii; Nasser Fatouraee
Volume 15, Issue 4 , March 2022, , Pages 299-312
Abstract
Considering the common diseases that occur in the heart valves, it is possible that these valves can be replaced with artificial valves. This article examines different types of polymeric valves for the possibility of replacement in the human body. Different models are compared and the optimal valve ...
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Considering the common diseases that occur in the heart valves, it is possible that these valves can be replaced with artificial valves. This article examines different types of polymeric valves for the possibility of replacement in the human body. Different models are compared and the optimal valve is presented. For complete information, refer to the text of the article.
Reza Sahebi Kuzeh Kanan; Hanieh Niroomand-Oscuii; Kohyar Yazdanpanah-Ardakani
Volume 13, Issue 4 , December 2019, , Pages 315-326
Abstract
Nowadays, patients crowd suffering from heart disease are increasing along with the development of technology and mechanized life. On the other hand, donor hearts ready for transplantation is limited in the world. Therefore, exploiting blood pumps is a suitable alternative for helping the patient during ...
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Nowadays, patients crowd suffering from heart disease are increasing along with the development of technology and mechanized life. On the other hand, donor hearts ready for transplantation is limited in the world. Therefore, exploiting blood pumps is a suitable alternative for helping the patient during the waiting time and even until the end of life. The blood pumps should be able to satisfy the biological needs, including proper output pressure and flow rate, in an acceptable margin of safety in terms of blood injuries. Reduction of pump size, blood exposure time and blood damages such as hemolysis are mentioned as the important challenges in the design of blood pumps. 30% of the patients who are using a left ventricle blood pump, required right ventricle blood pump due to right ventricle failure. Fulfilling the physiological requirement of right ventricle a RVAD must generate pressure in the range of 15-25 mmHg and flow rate equal to 5 L/min. generation of pressure over 25 mmHg will lead to pulmonary hypertension and its consequent problems. In this research, a centrifugal blood pump is designed for the right ventricle with an emphasis on impeller geometry. This pump is simulated for rotational speeds of 1500, 2000 rpm and flow rates of 4-6 L/min by using the computational fluid dynamics. The designed pump produces a flow rate of 5 L/min at 1500 rpm and a pressure of 23 mmHg. The amount of the hemolysis index calculated by the Lagrangian method is 0.00413.
Behrouz Jafarzadeh; Hanieh Niroomand-Oscuii; Farzan Ghalichi
Volume 12, Issue 4 , January 2019, , Pages 287-297
Abstract
Mock circulation systems are necessary for in vitro experiments and development of the ventricular assist devices, heart valves, total artificial hearts, artificial lungs, vascular grafts and intra-aortic balloon pumps. Tissue engineering of heart valves and other preliminary studies on the cardiovascular ...
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Mock circulation systems are necessary for in vitro experiments and development of the ventricular assist devices, heart valves, total artificial hearts, artificial lungs, vascular grafts and intra-aortic balloon pumps. Tissue engineering of heart valves and other preliminary studies on the cardiovascular system can also achieve with mock circulation systems. One of the major parts of these systems is generating of pulsatile flows like heart. In this study a mock circulation system with ability of physiological pressure and flow simulation in both healthy and diseases heart has been designed and manufactured. This setup can produce pressure and flow pulse by using a positive displacement pump with programing of movement pattern of stepper motor. This pump was manufactured after designing by Solid-works software for using in the mock circulation system. For testing this setup, several experiments with different values of peripheral resistance and arterial compliance and changing the pattern of the stepper motor have been performed. The results show modifying the pattern of the stepper motor from uniform speed to variable speed in one cycle (360 degree), as well as changing in arterial compliance and peripheral resistance, can produce waveform of physiological pressure and flow. The results confirm the reliable performance of this system in simulating physiological conditions. The designed system has the software capability to generate different waveforms.
Artificial Organs
Erfan Nammakie; Hanieh Niroomand Oscuii; Farzan Ghalichi; Mojtaba Koochaki
Volume 9, Issue 2 , July 2015, , Pages 133-142
Abstract
Myocardial diseases are on the rise all over the world and due to lack of sufficient donors, heart transplants are not the perfect solutions to treat all patients with heart failure. Therefore, in recent years, blood pumps have received a worldwide admissibility and have become the unrivalled tools for ...
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Myocardial diseases are on the rise all over the world and due to lack of sufficient donors, heart transplants are not the perfect solutions to treat all patients with heart failure. Therefore, in recent years, blood pumps have received a worldwide admissibility and have become the unrivalled tools for replacing a failed heart. In addition to biological needs such as sufficient head and flow rate, an assist blood pump should be in an acceptable margin of safety in terms of blood injuries such as hemolysis and thrombosis. Reducing blood damages, minimizing dimensions, reducing exposure time and simulating blood flow of natural heart are amongst the greatest challenges in designing assist blood pumps. One of the most important factors in determining the amount of blood injuries inside the pump is the blades’ shape of different parts of the pump. Studies have been conducted about heart pumps show that it is feasible to increase the efficiency of the pump and reduce the stagnation points that lead tothrombus formation by changing the type of blades of the impeller. The purpose of this study is to compare the performance of several airfoils for the blades of the impeller of an assist heart pump in order to optimize the performance and efficiency of the pump and reduce blood damages.
Cardiovascular Biomechanics
Hamed Khalesi; Hanie Niroomand Oscuii; Farzan Ghalichi
Volume 5, Issue 2 , June 2011, , Pages 143-149
Abstract
Prediction of the relationship between different types of mechanical loading and the failure of the intervertebral disc is so important to identify the risk factors which are difficult to study in vivo and in vitro. On the basis of finite element methods some of these issues may be overcome enabling ...
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Prediction of the relationship between different types of mechanical loading and the failure of the intervertebral disc is so important to identify the risk factors which are difficult to study in vivo and in vitro. On the basis of finite element methods some of these issues may be overcome enabling more detailed assessment of the biomechanical behavior of the intervertebral disc. The objective of this paper is to develop a nonlinear axisymmetric poroelastic finite element model of lumbar motion segment and show its capability for studying the time-dependent response of disc. After comparison of the response of different models in quasi-static analysis, the poroelastic model of intervertebral disc is presented and the results of short-term, long-term creep tests and cyclic loading were investigated. The results of the poroelastic model are in agreement with experimental ones reported in the literature. Hence, this model can be used to study how different dynamic loading regimes are important as risk factors for initiation of intervertebral disc degeneration.
Fluid-Structure Interaction in Biological Media / FSI
Hamed Khalesi; Hanie Niroomand Oscuii; Farzan Ghalichi
Volume 5, Issue 1 , June 2011, , Pages 67-78
Abstract
Biomechanics believe that, the arteries are remodeled under the influence of hemodynamic and mechanical factors. Biomechanical factors such as Opening Angle and the Tethering could have important effects on this phenomenon. The effects of various Opening Angle and Tethering during thoracic aorta aging ...
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Biomechanics believe that, the arteries are remodeled under the influence of hemodynamic and mechanical factors. Biomechanical factors such as Opening Angle and the Tethering could have important effects on this phenomenon. The effects of various Opening Angle and Tethering during thoracic aorta aging on arterial wall stress have been studied. ADINA software is used for numerical simulation.In this study, for the first time, numerical methods of Fluid-Structure Interaction have been used to study and simulate effects of Opening Angle and the Tethering in elastic artery remodeling due to age. Large deformation theory has been used for modeling changes of arterial radius; furthermore, behavior of Newtonian fluid has been used for blood. Pulsatile pressure and physiological Pulsatile flow waveforms have been applied to simulate transient behavior of arterial system. The results show that opening angle has further effect on circumferential stress so smooth distribution of circumferential stress on the wall accrued. Also, increasing Opening Angle with age reverses the circumferential stress distribution slop across the arterial wall. Tethering has further effect on axial stress. Decreasing Tethering in remodeling process over age leads to increase stress levels in the aged artery. Also, arterial wall shear stress in remodeled artery shows significant reduction in maximum, mean and amplitude values that caused reduction of pathological effects of endothelial cells.
Fluid-Structure Interaction in Biological Media / FSI
Hanie Niroomand Oscuii; Farzan Ghalichi; Mohammad Tafazzoli Shadpour
Volume 2, Issue 1 , June 2008, , Pages 1-8
Abstract
In this paper, we studied the effect of mechanical loading on remodeling process with aging in muscular arteries. Based on the gathered experimental data, the brachial artery was selected for simulation. In this simulation, pulsatile pressure and flow waves were considered as boundary conditions to study ...
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In this paper, we studied the effect of mechanical loading on remodeling process with aging in muscular arteries. Based on the gathered experimental data, the brachial artery was selected for simulation. In this simulation, pulsatile pressure and flow waves were considered as boundary conditions to study the effect of circumferential stress and wall shear stress on the remodeling process. FSI based transient numerical simulation was used to solve the fluid and solid equations. The results of three remodeling schemes showed that inward eutrophic scheme is an optimum algorithm for brachia! Artery remodeling with aging. Such remodeling scheme causes the most optimized outcome to keep circumferential stress with minimal alteration.
