Publication Date
2017
Document Type
Thesis
Committee Members
George Huang (Advisor), James Menart (Committee Member), Philippe Sucosky (Committee Member)
Degree Name
Master of Science in Mechanical Engineering (MSME)
Abstract
The systemic circulation has a large number of vessels; therefore, 3-D simulation of pulse-wave propagation in the entire cardiovascular system is difficult and computationally expensive. Zero-Dimensional (Zero-D) and One-Dimensional (1-D) models are simplified representations of the cardiovascular network; they can be coupled as supplements to regional 3-D models for closed-loop multi-scale studies or be simulated as self-sufficient representations of the blood-flow network. Unlike Zero-D models, 1-D models can provide linear space-wise information for the vessels. However, Zero-D models can prove to be more useful in particular cases; as flexibility in adjusting parameters facilitate in tailoring the model to specific needs. A prevalent reservation regarding the Zero-D models has been the inconsistency of parameter adjustment. A primary objective of this work is to build a closed loop cardiovascular model with a consistent, easily replicable methodology so that the model (1) can be adopted in multi-scale studies and (2) can provide a quick clinical tool for patient-specific studies. Fifty-five large arteries were represented individually and the rest of the cardiovascular network was lumped into several equivalent components. This way, arbitrary parameter adjustments have been restricted to the microcirculation and venous sections only. The model was validated by comparing simulated hemodynamic properties with clinical measurements and simulations from a comparable 1-D model. The Zero-D simulations have been shown to be in excellent agreement with the 1-D predictions, despite their discrete nature in space being contrary to linearly continuous 1-D counterpart. An advantageous characteristic of the developed model is the retention of physiological definitions, especially for the arterial network. Therefore, the model can be conveniently modified for patient-specific simulations. The generality of the method and closed-loop nature of the model also allow to inquisitively study various mathematical assumptions in blood flow modeling and experimental techniques. As an example, a possible source of non-physiological wave reflections has been studied in this thesis. The developed Zero-D model was found to be quite sensitive to the diastolic function of the left ventricle (LV). Therefore, several aspects of the mathematical modeling of ventricular elastance and LV-aorta coupling have been investigated in terms of measured responses from a healthy heart. Moreover, a few conventional assumptions of Zero-D modeling have been studied and found to be quite accurate with respect to 1-D simulations. Finally, the scopes for future studies and suitability of the model to certain applications have been discussed.
Page Count
104
Department or Program
Department of Mechanical and Materials Engineering
Year Degree Awarded
2017
Copyright
Copyright 2017, all rights reserved. My ETD will be available under the "Fair Use" terms of copyright law.
