The orthotropic viscoelastic behavior of aortic elastin

Area of Science:

• Biomaterials Science
• Biomechanics
• Cardiovascular Research

Background:

• Aortic elastin is a key component of the arterial wall, influencing its mechanical properties.
• Understanding elastin's viscoelastic behavior is essential for comprehending vascular mechanics and disease.
• Previous models often oversimplify the complex time-dependent responses of elastin.

Purpose of the Study:

• To investigate the viscoelastic behaviors of isolated aortic elastin.
• To develop and validate a computational model for elastin's orthotropic hyperelasticity and viscoelasticity.
• To compare the mechanical properties of isolated elastin with intact and decellularized aorta.

Main Methods:

• Performed biaxial stress relaxation and creep experiments on isolated aortic elastin.
• Utilized a quasi-linear viscoelasticity model integrated with a statistical mechanics-based eight-chain microstructural model.
• Developed a user material subroutine for finite element analysis (FEA).

Main Results:

• Stress relaxation preconditioning is necessary for repeatable results in elastin.
• Elastin exhibits less stress relaxation and negligible creep compared to intact or decellularized aorta.
• The developed model accurately simulates elastin's orthotropic hyperelasticity and viscoelasticity.

Conclusions:

• Isolated aortic elastin has distinct viscoelastic properties compared to the whole aorta.
• The integrated microstructural and viscoelastic model effectively captures elastin's mechanical behavior.
• This model provides a valuable tool for simulating vascular tissue mechanics.