Design and build of artificial blood vessels with variable compliance

Abstract

To more accurately recreate hemodynamic conditions in a benchtop circulatory simulator, it is important to develop artificial blood vessels with tunable mechanical characteristics. These vessels simulate the varying properties of blood vessels at different regions within the circulatory system by mimicking the compliance and therefore recreating physiological flow velocities and pressure waveforms. The compliance of a blood vessel defines how its volume will change in response to a pressure change. This project recreates variable compliance through a mechanism called laminar jamming, which utilizes friction between layers to tune the stiffness of a composite material. In the first experiment, a sample of composites with a wide range of materials and designs were tested, and looped materials exhibited behavior most similar to the mechanics of blood vessels. In the second experiment, a sample of looped materials was tested to further characterize the effects of different parameters on the composite's response to laminar jamming. Finally, in the third experiment, laminar jamming was applied to a tubular composite to mimic the shape of a blood vessel, and changes in the artificial vessel's compliance were observed through its volume-pressure relationship. These artificial vessels will be incorporated into a benchtop circulatory simulator to mimic disease physiology and evaluate cardiovascular support devices.