NUMERICAL SIMULATION OF HUMAN SYSTEMIC ARTERIAL HEMODYNAMICS BASED ON A TRANSMISSION LINE MODEL AND RECURSIVE ALGORITHM

2012 ◽  
Vol 12 (01) ◽  
pp. 1250020 ◽  
Author(s):  
WEI HE ◽  
HANGUANG XIAO ◽  
XINGHUA LIU
Keyword(s):  
Blood Pressure ◽  
Transmission Line ◽  
Input Impedance ◽  
Recursive Algorithm ◽  
Ascending Aorta ◽  
Transmission Line Model ◽  
Arterial Tree ◽  
Line Model ◽  
Arterial Hemodynamics ◽  
Flow Waveforms

A novel recursive algorithm was proposed to calculate the input impedance of human systemic arterial tree, and to simulate the human systemic arterial hemodynamics with an 55 segment transmission line model. In calculation of input impedance, the structure of the arterial tree was expressed as a single linked list. An infinitesimal constant was used to replace 0 Hz frequency to calculate the DC and AC part of input impedance simultaneously. The input impedance at any point of the arterial tree can obtain easily by the proposed recursive algorithm. The results of input impedance are in accord with experimental data and other models' results. In addition, some comparisons were conducted about the effects of arterial compliance, length, internal radius and wall thickness on the input impedance of ascending aorta. The results showed input impedances of ascending aorta displayed significantly different characteristics for different kinds of parameters. Finally, the blood pressure and flow waveforms of all arterial segments were calculated and displayed in 3D. The arterial elasticity and viscosity were discussed by changing the Young's modulus and the phase difference, respectively. The simulation results showed that the blood pressure and flow waveforms of the arterial tree reflected accurately the main characteristic features of physiopathological changes, which demonstrated the effectiveness of the proposed model.

MODELING AND HEMODYNAMIC SIMULATION OF HUMAN ARTERIAL STENOSIS VIA TRANSMISSION LINE MODEL

2016 ◽  
Vol 16 (05) ◽  
pp. 1650067 ◽  
Author(s):  
HANGUANG XIAO ◽  
ALBERTO AVOLIO ◽  
MINGFU ZHAO
Keyword(s):  
Blood Pressure ◽  
Transmission Line ◽  
Artery Stenosis ◽  
Arterial Stenosis ◽  
Transmission Line Model ◽  
Arterial Tree ◽  
Human Artery ◽  
Line Model ◽  
Hemodynamic Characteristics ◽  
Flow Waveforms

Arterial stenosis plays a key role in the development and formation of cardiovascular diseases. The effects of arterial stenosis on the global hemodynamic characteristics of human artery tree were studied based on a previously proposed transmission line model of 55 segment arterial tree. Different position, degree and length of the arterial stenosis were simulated to discuss the changes of blood pressure and flow waveform in human arterial tree. The stenosis degree of 50% to 90% were specified to represent a mild, moderate or severe stenosis. Three representative stenosis positions: aorta, carotid and iliac artery were selected. The stenosis length was specified to be 1[Formula: see text]cm to 4[Formula: see text]cm. The results of simulation were compared with the literature data. And ankle branchial index (ABI) was calculated to show its relationship with the stenosis position. The results showed that the influence of aorta stenosis on the blood pressure and flow waveforms of upstream artery is more obvious than those of downstream artery; branch artery stenosis has more influence on the blood pressure and flow waveforms of downstream artery than those of upstream artery. When the stenosis degree increased to 80%, the blood pressure and flow waveforms are affected significantly. The stenosis length causes a obvious change in the pressure and flow waveforms of stenosis inlet and outlet. The comparisons of literature and ABI demonstrated that the modeling method is a feasible tool to simulate and study the hemodynamics of the human artery stenosis.

scholarly journals Arterial viscoelasticity: role in the dependency of pulse wave velocity on heart rate in conduit arteries

2017 ◽  
Vol 312 (6) ◽  
pp. H1185-H1194 ◽  
Author(s):  
Hanguang Xiao ◽  
Isabella Tan ◽  
Mark Butlin ◽  
Decai Li ◽  
Alberto P. Avolio
Keyword(s):  
Heart Rate ◽  
Pulse Wave Velocity ◽  
Transmission Line ◽  
Wave Velocity ◽  
Pulse Wave ◽  
Large Artery ◽  
Transmission Line Model ◽  
Arterial Tree ◽  
Line Model ◽  
Physiological Studies

Experimental investigations have established that the stiffness of large arteries has a dependency on acute heart rate (HR) changes. However, the possible underlying mechanisms inherent in this HR dependency have not been well established. This study aimed to explore a plausible viscoelastic mechanism by which HR exerts an influence on arterial stiffness. A multisegment transmission line model of the human arterial tree incorporating fractional viscoelastic components in each segment was used to investigate the effect of varying fractional order parameter (α) of viscoelasticity on the dependence of aortic arch to femoral artery pulse wave velocity (afPWV) on HR. HR was varied from 60 to 100 beats/min at a fixed mean flow of 100 ml/s. PWV was calculated by intersecting tangent method (afPWVTan) and by phase velocity from the transfer function (afPWVTF) in the time and frequency domain, respectively. PWV was significantly and positively associated with HR for α ≥ 0.6; for α = 0.6, 0.8, and 1, HR-dependent changes in afPWVTan were 0.01 ± 0.02, 0.07 ± 0.04, and 0.22 ± 0.09 m/s per 5 beats/min; HR-dependent changes in afPWVTF were 0.02 ± 0.01, 0.12 ± 0.00, and 0.34 ± 0.01 m/s per 5 beats/min, respectively. This crosses the range of previous physiological studies where the dependence of PWV on HR was found to be between 0.08 and 0.10 m/s per 5 beats/min. Therefore, viscoelasticity of the arterial wall could contribute to mechanisms through which large artery stiffness changes with changing HR. Physiological studies are required to confirm this mechanism. NEW & NOTEWORTHY This study used a transmission line model to elucidate the role of arterial viscoelasticity in the dependency of pulse wave velocity on heart rate. The model uses fractional viscoelasticity concepts, which provided novel insights into arterial hemodynamics. This study also provides a means of assessing the clinical manifestation of the association of pulse wave velocity and heart rate.

Model Order Reduction of Transmission Line Model

2020 ◽  
Vol 19 ◽  
Keyword(s):  
Transmission Line ◽  
Large Scale ◽  
Original System ◽  
Reduced Order Model ◽  
Benchmark Problems ◽  
Transmission Line Model ◽  
Order Model ◽  
Line Model ◽  
Reduced Order ◽  
Numerical Effort

Transmission Line model are an important role in the electrical power supply. Modeling of such system remains a challenge for simulations are necessary for designing and controlling modern power systems.In order to analyze the numerical approach for a benchmark collection Comprehensive of some needful real-world examples, which can be utilized to evaluate and compare mathematical approaches for model reduction. The approach is based on retaining the dominant modes of the system and truncation comparatively the less significant once.as the reduced order model has been derived from retaining the dominate modes of the large-scale stable system, the reduction preserves the stability. The strong demerit of the many MOR methods is that, the steady state values of the reduced order model does not match with the higher order systems. This drawback has been try to eliminated through the Different MOR method using sssMOR tools. This makes it possible for a new assessment of the error system Offered that the Observability Gramian of the original system has as soon as been thought about, an H∞ and H2 error bound can be calculated with minimal numerical effort for any minimized model attributable to The reduced order model (ROM) of a large-scale dynamical system is essential to effortlessness the study of the system utilizing approximation Algorithms. The response evaluation is considered in terms of response constraints and graphical assessments. the application of Approximation methods is offered for arising ROM of the large-scale LTI systems which consist of benchmark problems. The time response of approximated system, assessed by the proposed method, is also shown which is excellent matching of the response of original system when compared to the response of other existing approaches .

Transmission line model for superconducting coplanar lines

1990 ◽  
Vol 26 (2) ◽  
pp. 148 ◽  
Author(s):  
D. Kinowski ◽  
C. Seguinot ◽  
P. Pribetich ◽  
P. Kennis
Keyword(s):  
Transmission Line ◽  
Transmission Line Model ◽  
Line Model
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