Phase-field approach to model fracture in human aorta

Date

2019-08-23

Author

Gültekin, Osman
Holzapfel, Gerhard A.
Dal, Hüsnü

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Over the last decades the supra-physiological and pathological aspects of arterial tissues have become a prominent research topic in computational biomechanics in terms of constitutive modeling considering damage and fracture [1]. The current study presents a variational approach to the fracture of human arterial walls, featuring a thermodynamically consistent, gradient-type, diffusive crack phase-field approach. A power balance renders the Euler-Lagrange equations of the multi-field problem, i.e. the deformation and the phase-field. The respective constitutive model is essentially anisotropic and in accordance with the tissue morphology. A novel anisotropic phase-field model accounts for not only the altered crack patterns with respect to the orientation collagen fibers, but also the distinct strain-energy contributions due to isotropic and anisotropic parts [2, 3, 4]. The prediction of the crack pattern are studied via single edge-notched tests to ascertain anisotropic features of the model. Aside from that, a novel simple concept of design, i.e. an idealized cylindrical model of the multi-layered thoracic aortic wall with a notch representing the initial tear provides insights regarding the nascent crack growth associated with aortic dissection. In particular, the analysis indicates crack onset and progression around the initial tear while aligning with the direction of the first fiber family, capturing the helical pattern of the aortic dissection in the aorta [4]. The results also lay bare the need for a systematic experimental characterization of the human aorta for an inclusive parameter identification. References: 1. O. Gültekin and G. A. Holzapfel (2018). A brief review on computational modeling of rupture in soft biological tissues. Computational methods in applied sciences. In E. Onate, D. Peric, E. de Souza Neto, and M. Chiumenti, editors, Advances in Computational Plasticity. A Book in Honour of D. Roger J. Owen, volume 46(6), pages 113-144. Springer Nature. 2. O. Gültekin, H. Dal, and G. A. Holzapfel (2016). A phase-field approach to model fracture of arterial walls: theory and finite element analysis. Comput. Meth. Appl. Mech. Eng., 312: 542- 566. 3. O. Gültekin, H. Dal, and G. A. Holzapfel (2018). Numerical aspects of anisotropic failure in soft biological tissues favor energy-based criteria: A rate-dependent mixed crack phase-field model. Comput. Meth. Appl. Mech. Eng. 331: 23-52. 4. O. Gültekin, S.P. Hager, H. Dal, and G. A. Holzapfel. Computational modeling of progressive damage and rupture in fibrous biological tissues: Application to aortic dissection. Biomech. Model. Mechanobiol., (submitted)

URI

http://iwpdf.ae.metu.edu.tr/book_of_abstracts.pdf#page=35
https://hdl.handle.net/11511/83566

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