Characterizing the inhomogeneity of aorta mechanical properties and its effect on the prediction of injury

Kermani, Golriz; Assari, Soroush; Hemmasizadeh, Ali; Darvish, Kurosh

Affiliations

¹Biomechanics Lab, Department of Mechanical Engineering, Temple University

Abstract

Traumatic aortic rupture (TAR) is one of the most significant causes of motor-vehicle fatalities with the majority of injuries occurring in the peri-isthmus region. Despite the fact that TAR accounts for 20% of the total automobile fatalities, there is uncertainty regarding its etiology and underlying mechanisms. Finite element (FE) models are essential for calculating the strains and stresses in aorta during car accidents leading to TAR and assessing the risk of injury and/or failure. Current FE models of the thorax generally consist of simplistic material models for the aorta with the assumptions of isotropy and homogeneity. In order to develop reliable FE models, suitable constitutive relationships are needed which account for the rate dependency, nonlinearity, inhomogeneity, and anisotropy of the aortic tissue. The objectives of this study were twofold. The first objective was to investigate the inhomogeneity of porcine descending thoracic aorta (DTA) using a custom-made nano-indentation test setup. The second objective was to investigate the risk of aortic failure in car accidents by implementing the inhomogeneity of aorta in the Global Human Body Model (GHBM). Changes in stress and strain distributions and the effect of aortic inhomogeneity were evaluated in frontal chest impacts. The results from nanoindentations in the axial orientation showed that distal sections are stiffer than the proximal ones and the medial quadrant shows the least stiff behavior. Results from FE simulations suggest that implementing the inhomogeneity of the aortic tissue had the most influence on the isthmus and ATA regions.

Links

URL: http://ibrc.osu.edu/wp-content/uploads/2015/05/Kermani_Manuscript_2016.pdf

Cited Works (6)

Year	Entry
2001	Shah CS, Yang KH, Hardy W, Wang HK, King AI. Development of a computer model to predict aortic rupture due to impact loading. Stapp Car Crash J. 2001;45:161-182. SAE 2001-22-0007.
2006	Shah CS, Hardy WN, Mason MJ, Yang KH, Van Ee C, Morgan R, Digges K. Dynamic biaxial tissue properties of the human cadaver aorta. Stapp Car Crash J. 2006;50:217-246. SAE 2006-22-0010.
1983	Mohan D, Melvin JW. Failure properties of passive human aortic tissue, II: biaxial tension tests. J Biomech. 1983;16(1):31-44.
2009	Yuen KF. The Development of a Numerical Human Body Model for the Analysis of Automotive Side Impact Lung Trauma [Master's thesis]. University of Waterloo; 2009.
1965	Sneddon IN. The relation between load and penetration in the axisymmetric Boussinesq problem for a punch of arbitrary profile. Int J Eng Sci. May 1965;3(1):47-57.
1999	Deng Y-C, Kong W, Ho H. Development of a finite element human thorax model for impact injury studies. In: Proceedings of the SAE International Congress & Exposition. March 1-4, 1999; Detroit, MI. Warrendale, PA: Society of Automotive Engineers. SAE 1999-01-0715.