www.elsevier.com/locate/jmbbm Available online at www.sciencedirect.com Research Paper Experimental and constitutive modeling approaches for a study of biomechanical properties of human coronary arteries Malgorzata A. Jankowska a,n , Magdalena Bartkowiak-Jowsa b,c,1 , Romuald Bedzinski d,2 a Poznan University of Technology, Institute of Applied Mechanics, Jana Pawla II 24, 60-965 Poznan, Poland b Wroclaw University of Technology, Institute of Machine Design and Operation, Lukasiewicza 7/9, 50-371 Wroclaw, Poland c Wrovasc - Integrated Cardiovascular Centre, Regional Specialist Hospital, Research and Development Centre, Kamienskiego 83a, 51-124 Wroclaw, Poland d University of Zielona Gora, Institute of Mechanical Engineering and Machine Operation, Division of Biomedical Engineering, Podgorna 50, 65-246 Zielona Gora, Poland article info Article history: Received 19 February 2015 Received in revised form 19 May 2015 Accepted 21 May 2015 Available online 2 June 2015 Keywords: Biomechanical properties of arterial walls Human coronary arteries Atherosclerosis Constitutive models abstract The study concerns the determination of mechanical properties of human coronary arterial walls with both experimental and constitutive modeling approaches. The research material was harvested from 18 patients (range 50-84 years). On the basis of hospital records and visual observation, each tissue sample was classified according to the stage (0, I, II, III) of atherosclerosis development (SAD). Then, strip samples considered as a membrane with the shape of rectangular parallelepiped were preconditioned and sub- jected to uniaxial tensile tests in longitudinal (n=27) and circumferential (n=4) direction. With experimental data obtained, the stress-strain characteristics were prepared. Further- more, tensile strengths and related strains, stiffness coefficients and tangent modules of elasticity were computed. For a constitutive model of passive mechanical behavior of coronary arteries, values of material parameters were computed. The studies led to the following conclusions. Most importantly, the atherosclerotic changes affect all the mechanical properties of arterial walls. A progress of arteriosclerosis contributes to an increase of vascular stiffness. The highest values of the stiffness coefficients are obtained for the tissues in the advanced stage of the disease. We were also able to observe that gradual calcification, progression of atherosclerosis and degradation of collagen in the tissue caused a decrease of tensile strengths and related strains. Finally, a comparison http://dx.doi.org/10.1016/j.jmbbm.2015.05.021 1751-6161/& 2015 Elsevier Ltd. All rights reserved. n Corresponding author. Tel.: þ48 616652069; fax: þ48 616652307. E-mail addresses: malgorzata.jankowska@put.poznan.pl (M.A. Jankowska), magdalena.jowsa@gmail.com (M. Bartkowiak-Jowsa), romuald.bedzinski@pwr.edu.pl (R. Bedzinski). 1 Tel.: þ48 71 320 20 90; fax: þ48 71 322 76 45. 2 Tel./fax: þ48-68-328-24-90. journal ofthe mechanical behavior of biomedical materials 50 (2015)1–12