Reinforced Elastomer Composites and Metamaterials for Neo-aorta Applications

  • Author / Creator
    Zhalmuratova, Dinara
  • This thesis describes materials and strategies developed to replace rigid and noncompliant plastic tube, which causes injuries to the heart at the junction between the tissue and the tube in an ex-vivo heart perfusion device. The research is composed of two main parts. The first part addresses mimicking the rapidly strain-stiffening J-shaped and anisotropic stress-strain behavior of human and porcine aorta, necessary for producing the Windkessel effect to ensure continuous blood flow through the aorta. First, the mechanical properties of human and porcine aorta were measured to quantify the nonlinear and anisotropic behavior under uniaxial tensile stress. Secondly, fabric-reinforced elastomer composites were prepared by reinforcing silicone elastomers with embedded knitted fabrics in trilayer geometry. Finally, improved analytical constitutive models based on Gent’s and Mooney-Rivlin’s constitutive model (to describe the elastomer matrix) combined with Holzapfel–Gasser–Ogden’s model (to represent the stiffer fabrics) were developed to verify aorta-like behavior of fabric-reinforced composites. The second part of this thesis included design of a material that limits the peak pressure in aorta by expanding to accommodate a large stroke volume. Recent advances in additive manufacturing techniques have enabled the development of novel materials with enhanced mechanical properties derived from carefully designed geometry known as metamaterials. To eliminate the consequences of aortic stiffening at high pressure, a metamaterial with unique strain-softening property at peak pressure coming after J-shaped strain-stiffening property is proposed. Thus, the second part of this thesis includes a thorough review covering design criteria and fabrication strategies of the bioinspired metamaterials, followed by a few of my original experimental trials.

  • Subjects / Keywords
  • Graduation date
    Fall 2019
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
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