A strain energy function for arteries accounting for wall composition and structure.

Area of Science:

• Biomechanics
• Biomaterials Science
• Computational Biology

Background:

• Strain Energy Functions (SEFs) model soft biological tissue mechanics.
• Classic SEFs often overlook structural details of tissues like arterial walls.
• Previous structural SEFs, like Holzapfel et al., improved modeling by including collagen fiber angles.

Purpose of the Study:

• To develop a novel structural Strain Energy Function (SEF) for soft biological tissues.
• To incorporate collagen waviness and the fractional composition of elastin and collagen into the SEF.
• To evaluate the performance of the new SEF against existing models using experimental data.

Main Methods:

• Developed a novel SEF accounting for collagen waviness (log-logistic distribution) and tissue composition.
• Applied the novel SEF to fit experimental data from rat carotid artery inflation-extension tests.
• Compared the novel SEF's fit quality and parameter interpretability against Chuong-Fung and Holzapfel et al. SEFs.

Main Results:

• The novel SEF demonstrated comparable fit quality to the Holzapfel et al. SEF in describing arterial pressure-radius curves.
• Both models successfully captured the characteristic S-shaped response of the arterial wall.
• Derived SEF parameters (elastic moduli, collagen waviness, fiber angle) showed physical relevance and were compared to experimental findings.

Conclusions:

• The developed structural SEF provides a more comprehensive model for arterial wall mechanics.
• Incorporating collagen waviness and tissue composition enhances the accuracy and physical interpretability of SEFs.
• This novel SEF is suitable for applications like finite element modeling of soft biological tissues.