On the computation of in vivo transmural mean stress of patient-specific aortic wall

Minliang Liu, Liang Liang, Haofei Liu, Ming Zhang, Caitlin Martin, Wei Sun

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

It is well known that residual deformations/stresses alter the mechanical behavior of arteries, e.g., the pressure–diameter curves. In an effort to enable personalized analysis of the aortic wall stress, approaches have been developed to incorporate experimentally derived residual deformations into in vivo loaded geometries in finite element simulations using thick-walled models. Solid elements are typically used to account for “bending-like” residual deformations. Yet, the difficulty in obtaining patient-specific residual deformations and material properties has become one of the biggest challenges of these thick-walled models. In thin-walled models, fortunately, static determinacy offers an appealing prospect that allows for the calculation of the thin-walled membrane stress without patient-specific material properties. The membrane stress can be computed using forward analysis by enforcing an extremely stiff material property as penalty treatment, which is referred to as the forward penalty approach. However, thin-walled membrane elements, which have zero bending stiffness, are incompatible with the residual deformations, and therefore, it is often stated as a limitation of thin-walled models. In this paper, by comparing the predicted stresses from thin-walled models and thick-walled models, we demonstrate that the transmural mean stress is approximately the same for the two models and can be readily obtained from in vivo clinical images without knowing the patient-specific material properties and residual deformations. Computation of patient-specific mean stress can be greatly simplified by using the forward penalty approach, which may be clinically valuable.

Original languageEnglish (US)
Pages (from-to)387-398
Number of pages12
JournalBiomechanics and Modeling in Mechanobiology
Volume18
Issue number2
DOIs
StatePublished - Apr 15 2019
Externally publishedYes

Keywords

  • Forward penalty approach
  • Membrane stress
  • Residual stress
  • Transmural mean stress

ASJC Scopus subject areas

  • Biotechnology
  • Modeling and Simulation
  • Mechanical Engineering

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