Nonlinear dynamics of human aortas for viscoelastic mechanical characterization

The results of this work present eleven human thoracic aortas tested on a mock circulatory loop (MCL) that was developed to simulate physiological pulsatile flow conditions. Results showed cyclic axisymmetric diameter changes, which were compatible with in-vivo cyclic diameter changes at resting heart rate. The dynamic stiffness increased with age, but the cyclic axisymmetric diameter variation decreased with age when at a resting pulse rate. The energy dissipation was also noted to decrease with increased age. The synergistic effects of the fluidstructure interaction and the viscoelasticity led to larger damping at higher pulse rates. The projected outcome of this work is creating innovative biomaterials that better reproduce the aortic dynamic behavior. The findings complement expanding avenues in advanced materials, with the aim of creating improved and mechanically compatible cardiovascular devices, like grafts and stents.