From Uniaxial Testing of Isolated Layers to a Tri-Layered Arterial Wall: A Novel Constitutive Modelling Framework

Alessandro Giudici, Ashraf W. Khir, Jason M. Szafron, Bart Spronck*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Web of Science)

Abstract

Mechanical testing and constitutive modelling of isolated arterial layers yields insight into the individual layers' mechanical properties, but per se fails to recapitulate the in vivo loading state, neglecting layer-specific residual stresses. The aim of this study was to develop a testing/modelling framework that integrates layer-specific uniaxial testing data into a three-layered model of the arterial wall, thereby enabling study of layer-specific mechanics under realistic (patho)physiological conditions. Circumferentially and axially oriented strips of pig thoracic aortas (n = 10) were tested uniaxially. Individual arterial layers were then isolated from the wall, tested, and their mechanical behaviour modelled using a hyperelastic strain energy function. Subsequently, the three layers were computationally assembled into a single flat-walled sample, deformed into a cylindrical vessel, and subjected to physiological tension-inflation. At the in vivo axial stretch of 1.10 +/- 0.03, average circumferential wall stress was 75 +/- 9 kPa at 100 mmHg, which almost doubled to 138 +/- 15 kPa at 160 mmHg. A similar to 200% stiffening of the adventitia over the 60 mmHg pressure increase shifted layer-specific load-bearing from the media (65 +/- 10% -> 61 +/- 14%) to the adventitia (28 +/- 9% -> 32 +/- 14%). Our approach provides valuable insight into the (patho)physiological mechanical roles of individual arterial layers at different loading states, and can be implemented conveniently using simple, inexpensive and widely available uniaxial testing equipment.

Original languageEnglish
Pages (from-to)2454-2467
Number of pages14
JournalAnnals of Biomedical Engineering
Volume49
Issue number9
Early online date3 Jun 2021
DOIs
Publication statusPublished - Sep 2021

Keywords

  • Tri-layered arterial wall model
  • Residual stresses
  • Layer-specific mechanics
  • Aorta
  • Arterial mechanics
  • BIAXIAL MECHANICAL-PROPERTIES
  • RESIDUAL DEFORMATIONS
  • THORACIC AORTA
  • TISSUE
  • MICROSTRUCTURE
  • COLLAGEN
  • STRAINS
  • ELASTIN

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