The Effect of Material Model Formulation in the Stress Analysis of Abdominal Aortic Aneurysms
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A reliable estimation of wall stress in Abdominal Aortic Aneurysms (AAAs), requires performing an accurate three-dimensional reconstruction of the medical image-based native geometry and modeling an appropriate constitutive law for the aneurysmal tissue material characterization. A recent study on the biaxial mechanical behavior of human AAA tissue specimens demonstrates that aneurysmal tissue behaves mechanically anisotropic. Results shown in this communication show that the peak wall stress is highly sensitive to the anisotropic model used for the stress analysis. In addition, the present investigation indicates that structural parameters (e.g., collagen fiber orientation) should be determined independently and not by means of non-linear fitting to stress–strain test data. Fiber orientation identified in this manner could lead to overestimated peak wall stresses.
KeywordsAneurysm Wall stress Anisotropy Soft tissue mechanics Computational modeling Rupture Biomechanics Thrombus
This work is supported in part by the Pennsylvania Infrastructure Technology Alliance (a partnership of Carnegie Mellon University, Lehigh University and the Commonwealth of Pennsylvania Department of Community and Economic Development), the Spanish Ministry of Science and Technology through research grant DPI2004-07410-C03-01, the University of Zaragoza, an allocation of advanced computing resources granted by the National Science Foundation through the TeraGrid project at the Pittsburgh Supercomputing Center, and NIH grants R21EB007651, from the National Institute of Biomedical Imaging and Bioengineering, and R15HL087268, from the National Heart, Lung, and Blood Institute. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
- 5.Holzapfel, G. A. Nonlinear Solid Mechanics. A Continuum Approach for Engineering. Chichester: Wiley, 2000.Google Scholar
- 7.Humphrey, J. D. Cardiovascular Solid Mechanics: Cells, Tissues, and Organs. New York: Springer-Verlag, 2002.Google Scholar
- 10.Martufi, G., J. F. Rodriguez, G. J. Parisi, M. Doblare, S. C. Muluk, and E. A. Finol. Nonlinear anisotropic stress analysis of anatomically realistic abdominal aortic aneurysms. J. Biomech. (submitted).Google Scholar
- 11.Raghavan, M. L., and D. A. Vorp. Toward a biomechanical tool to evaluate rupture potential of abdominal aortic aneurysm: identification of a finite strain constitutive model and evaluation of its applicability. J. Biomech. 33:475–482, 2000. doi: 10.1016/S0021-9290(99)00201-8.PubMedCrossRefGoogle Scholar
- 14.Shum, J., E. S. DiMartino, A. Goldhammer, D. Goldman, L. Acker, G. Patel, J. H. Ng, G. Martufi, and E. A. Finol. Semi-automatic vessel wall detection and quantification of wall thickness in computed tomography images of human abdominal aortic aneurysms. Med. Phys. (submitted).Google Scholar