مقاله A constitutive model for vascular tissue that integrates fibril, fiber and continuum levels with application to the isotropic and passive properties of the infrarenal aorta : تی پی بین

خلاصه مقاله

A fundamental understanding of the mechanical properties of the extracellular matrix (ECM) is critically important to quantify the amount of macroscopic stress and/or strain transmitted to the cellular level of vascular tissue. Structural constitutive models integrate histological and mechanical information, and hence, allocate stress and strain to the different microstructural components of the vascular wall. The present work proposes a novel multi-scale structural constitutive model of passive vascular tissue, where collagen fibers are assembled by proteoglycan (PG) cross-linked collagen fibrils and reinforce an otherwise isotropic matrix material. Multiplicative kinematics account for the straightening and stretching of collagen fibrils, and an orientation density function captures the spatial organization of collagen fibers in the tissue. Mechanical and structural assumptions at the collagen fibril level define a piece-wise analytical stress–stretch response of collagen fibers, which in turn is integrated over the unit sphere to constitute the tissue's macroscopic mechanical properties. The proposed model displays the salient macroscopic features of vascular tissue, and employs the material and structural parameters of clear physical meaning. Likewise, the constitutive concept renders a highly efficient multi-scale structural approach that allows for the numerical analysis at the organ level. Model parameters were estimated from isotropic mean-population data of the normal and aneurysmatic aortic wall and used to predict in-vivo stress states of patient-specific vascular geometries, thought to demonstrate the robustness of the particular Finite Element (FE) implementation. The collagen fibril level of the multi-scale constitutive formulation provided an interface to integrate vascular wall biology and to account for collagen turnover.

نویسندگان

Giampaolo Martufi [ Department of Solid Mechanics, School of Engineering Sciences, Royal Institute of Technology KTH, Osquars Backe 1, SE-100 44 Stockholm, Sweden ]

T. Christian Gasser [ Department of Solid Mechanics, School of Engineering Sciences, Royal Institute of Technology KTH, Osquars Backe 1, SE-100 44 Stockholm, Sweden ]

کلمات کلیدی

Collagen Microfiber Aneurysm Aorta Finite Element Multiscale

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journal Of Biomechanics

Journal of Biomechanics publishes reports of original and substantial findings using the principles of mechanics to explore biological problems. Analytical and experimental papers may be submitted, and the journal accepts original articles, surveys and perspective articles (usually by Editorial invitation only), book reviews and letters to the Editor. The criteria for acceptance of manuscripts include excellence, novelty, significance, clarity, conciseness and interest to the readership.

حوزه های تحت پوشش : مهندسی مکانیک، علوم فیزیک، علوم ریاضی