POLZER, Stanislav, Jiri BURSA, T Christian GASSER, Robert STAFFA and Robert VLACHOVSKÝ. A Numerical Implementation to Predict Residual Strains from the Homogeneous Stress Hypothesis with Application to Abdominal Aortic Aneurysms. ANNALS OF BIOMEDICAL ENGINEERING. NEW YORK: SPRINGER, 2013, vol. 41, No 7, p. 1516-1527. ISSN 0090-6964. doi:10.1007/s10439-013-0749-y.
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Basic information
Original name A Numerical Implementation to Predict Residual Strains from the Homogeneous Stress Hypothesis with Application to Abdominal Aortic Aneurysms
Authors POLZER, Stanislav (203 Czech Republic), Jiri BURSA (203 Czech Republic), T Christian GASSER (203 Czech Republic), Robert STAFFA (203 Czech Republic, belonging to the institution) and Robert VLACHOVSKÝ (203 Czech Republic, guarantor, belonging to the institution).
Edition ANNALS OF BIOMEDICAL ENGINEERING, NEW YORK, SPRINGER, 2013, 0090-6964.
Other information
Original language English
Type of outcome Article in a journal
Field of Study 30000 3. Medical and Health Sciences
Country of publisher United States of America
Confidentiality degree is not subject to a state or trade secret
Impact factor Impact factor: 3.231
RIV identification code RIV/00216224:14110/13:00070192
Organization unit Faculty of Medicine
Doi http://dx.doi.org/10.1007/s10439-013-0749-y
UT WoS 000320329200015
Keywords in English Residual stress; Abdominal aortic aneurysm; Finite element analysis; Patient-specific geometry
Tags International impact, Reviewed
Changed by Changed by: Soňa Böhmová, učo 232884. Changed: 20. 11. 2013 14:23.
Abstract
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.
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