Detail publikace

A numerical implementation to predict residual strains from the homogeneous stress hypothesis with application to abdominal aortic aneurysms

POLZER, S. BURŠA, J. GASSER, T. STAFFA, R. VLACHOVSKÝ, R.

Originální název

A numerical implementation to predict residual strains from the homogeneous stress hypothesis with application to abdominal aortic aneurysms

Typ

článek v časopise - ostatní, Jost

Jazyk

angličtina

Originální abstrakt

Wall stress analysis of abdominal aortic aneurysm (AAA) is a promising method of identifying AAAs at high risk of rupture. However, neglecting residual strains (RS) in the load-free configuration of patient-specific finite element analysis models is a sever limitation that strongly affects the computed wall stresses. Although several methods for including RS have been proposed, they cannot be directly applied to patient-specific AAA simulations. RS in the AAA wall are predicted through volumetric tissue growth that aims at satisfying the homogeneous stress hypothesis at mean arterial pressure load. Tissue growth is interpolated linearly across the wall thickness and aneurysm tissues are described by isotropic constitutive formulations. The total deformation is multiplicatively split into elastic and growth contributions, and a staggered schema is used to solve the field variables. The algorithm is validated qualitatively at a cylindrical artery model and then applied to patient-specific AAAs (n = 5). The induced RS state is fully three-dimensional and in qualitative agreement with experimental observations, i.e., wall strips that were excised from the load-free wall showed stress-releasing-deformations that are typically seen in laboratory experiments. Compared to RS-free simulations, the proposed algorithm reduced the von Mises stress gradient across the wall by a tenfold. Accounting for RS leads to homogenized wall stresses, which apart from reducing the peak wall stress (PWS) also shifted its location in some cases. The present study demonstrated that the homogeneous stress hypothesis can be effectively used to predict RS in the load-free configuration of the vascular wall. The proposed algorithm leads to a fast and robust prediction of RS, which is fully capable for a patient-specific AAA rupture risk assessment. Neglecting RS leads to non-realistic wall stress values that severely overestimate the PWS.

Klíčová slova

residual stress, abdominal aortic aneurysm, finite element analysis, patient-specific geometry

Autoři

POLZER, S.; BURŠA, J.; GASSER, T.; STAFFA, R.; VLACHOVSKÝ, R.

Rok RIV

2013

Vydáno

12. 6. 2013

Nakladatel

Springer

ISSN

0090-6964

Periodikum

ANNALS OF BIOMEDICAL ENGINEERING

Ročník

41

Číslo

7

Stát

Spojené státy americké

Strany od

1516

Strany do

1527

Strany počet

12

BibTex

@article{BUT101951,
  author="Stanislav {Polzer} and Jiří {Burša} and Thomas Christian {Gasser} and Robert {Staffa} and Robert {Vlachovský}",
  title="A numerical implementation to predict residual strains from the homogeneous stress hypothesis with application to abdominal aortic aneurysms",
  journal="ANNALS OF BIOMEDICAL ENGINEERING",
  year="2013",
  volume="41",
  number="7",
  pages="1516--1527",
  doi="10.1007/s10439-013-0749-y",
  issn="0090-6964"
}