A Study on the Response of Human Phantom Aorta to Externally Imposed Oscillations
Khan, Yusuf Liyakat
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This study of forced oscillation effects on phantom human aorta is a concept extended from previous research on airway smooth muscle to a study of aortic tissue, and the phenomena that induce oscillations in the aorta modelled as a fluid-conveying pipe. The study was carried out to measure the pressures and flows at different frequencies and amplitudes with material properties, the pulsatile nature of blood flow as distinct from respiration, and differing boundary conditions. Mathematical modelling, software simulation and experimental work on human phantom aorta were carried out. The simulation was done using Wolfram (Mathematica®10, USA) software. The 1-Dimension mathematical model for pressure and velocity was simulated for different signals and boundary conditions. The simulation was fitted with interpolation and to produce one beat with all the information to be repeated. The simulation response was compared with the experimental set up. The experimental set up, using the phantom human aorta, was used to verify the simulation responses. Dragon Skin®10 was used as material to make the phantom aorta. The phantom aorta was submerged in fluid (water) to give boundary conditions more similar to a human aorta for the readings. The readings used a function generator, LDS® V406 shakers along with LDS® PA 100E power amplifier and force displacement transducer to get output responses. The readings were taken from frequencies between 5 Hz to 49 Hz with 1-2 Vpp amplitude. The response to the forced oscillations were significant for the frequency range between 30 Hz and 35 Hz with maximum amplitude of 2 Vpp in excitation magnitude. However, the ascending aorta showed reduced values under the same conditions. In contrast, flow had a very weak response between 5 Hz to 20 Hz; only at higher frequencies flow did more vibrations occur which made the experimental set up unstable.