Publication detail
Importance of material model in wall stress prediction in abdominal aortic aneurysms
POLZER, S. GASSER, T. BURŠA, J. STAFFA, R. VLACHOVSKÝ, J. MAN, V. SKÁCEL, P.
Czech title
vliv modelu materiálu na napětí ve stěně aneurysmat břišní aorty
English title
Importance of material model in wall stress prediction in abdominal aortic aneurysms
Type
journal article - other
Language
en
Original abstract
Background. Results of biomechanical simulation of the abdominal aortic aneurysm (AAA) depend on the constitutive description of the wall. Based on in-vitro and in-vivo experimental data several constitutive models for the AAA wall have been proposed in literature. Those models differ strongly from each other and their impact on the computed stress in biomechanical simulation is not clearly understood. Methods. Finite Element (FE) models of AAAs from 7 patients who underwent elective surgical repair were used to compute wall stresses. AAA geometry was reconstructed from CT angiography (CTA) data and patient-specific constitutive descriptions of the wall were derived from planar biaxial testing of anterior wall tissue samples. In total 28 FE models were used, where the wall was described either by patient-specific or previously reported study-average properties. This data was derived from either uniaxial or biaxial in-vitro testing. Computed wall stress fields were compared on node-by-node basis. Results. Different constitutive models for the AAA wall cause significantly different predictions of wall stress. While study-average data from biaxial testing gives globally the same stress field as the patient-specific wall properties, the material model based on uniaxial test data overestimates the wall stress on average by 30kPa or about 67% of the mean stress. A quasi-linear description based on the in-vivo measured distensibility of the AAA wall leads to a completely altered stress field and overestimates the wall stress by about 75kPa or about 167% of the mean stress. Conclusion. The present study demonstrated that the constitutive description of the wall is crucial for AAA wall stress prediction. Consequently, results obtained using different models should not be mutually compared unless different stress gradients across the wall are not taken into account. Highly nonlinear material models should be preferred when the response of AAA to increased blood pressure is investigated, while the quasi-linear model with high initial stiffness produces negligible stress gradients across the wall and thus, it is more appropriate when response to mean blood pressure is calculated.
Czech abstract
viz popis v originále. Jedná se o článek popisující vliv modelu materiálu na napjatost aneurysmatu. Bylo prokázáno, že navzdory obecnému mínění, materiál s rozdílným stupněm nelinearity, vykazují významně různé napětí
English abstract
Background. Results of biomechanical simulation of the abdominal aortic aneurysm (AAA) depend on the constitutive description of the wall. Based on in-vitro and in-vivo experimental data several constitutive models for the AAA wall have been proposed in literature. Those models differ strongly from each other and their impact on the computed stress in biomechanical simulation is not clearly understood. Methods. Finite Element (FE) models of AAAs from 7 patients who underwent elective surgical repair were used to compute wall stresses. AAA geometry was reconstructed from CT angiography (CTA) data and patient-specific constitutive descriptions of the wall were derived from planar biaxial testing of anterior wall tissue samples. In total 28 FE models were used, where the wall was described either by patient-specific or previously reported study-average properties. This data was derived from either uniaxial or biaxial in-vitro testing. Computed wall stress fields were compared on node-by-node basis. Results. Different constitutive models for the AAA wall cause significantly different predictions of wall stress. While study-average data from biaxial testing gives globally the same stress field as the patient-specific wall properties, the material model based on uniaxial test data overestimates the wall stress on average by 30kPa or about 67% of the mean stress. A quasi-linear description based on the in-vivo measured distensibility of the AAA wall leads to a completely altered stress field and overestimates the wall stress by about 75kPa or about 167% of the mean stress. Conclusion. The present study demonstrated that the constitutive description of the wall is crucial for AAA wall stress prediction. Consequently, results obtained using different models should not be mutually compared unless different stress gradients across the wall are not taken into account. Highly nonlinear material models should be preferred when the response of AAA to increased blood pressure is investigated, while the quasi-linear model with high initial stiffness produces negligible stress gradients across the wall and thus, it is more appropriate when response to mean blood pressure is calculated.
Keywords in Czech
model materiálu, předpětí, břišní aneurysma, napětí ve stěně, analýza MKP
Keywords in English
material model, pre-stressing, abdominal aneurysm, wall stress, FE analysis
RIV year
2013
Released
27.01.2013
Publisher
Elsevier
ISSN
1350-4533
Volume
35
Number
4
Pages from–to
1282–1289
Pages count
8
BIBTEX
@article{BUT101734,
author="Stanislav {Polzer} and Thomas Christian {Gasser} and Jiří {Burša} and Robert {Staffa} and Jan {Vlachovský} and Vojtěch {Man} and Pavel {Skácel},
title="Importance of material model in wall stress prediction in abdominal aortic aneurysms",
year="2013",
volume="35",
number="4",
month="January",
pages="1282--1289",
publisher="Elsevier",
issn="1350-4533"
}