title: Investigation of the optimal collagen fibre orientation in human iliac arteries.
abstract: The distribution of collagen fibres plays a significant role in the mechanical behaviour of artery walls. Experimental data show that in most artery wall layers there are two (or more) in-plane symmetrically disposed families of fibres. However, a recent investigation revealed that some artery wall layers have only one preferred fibre direction, notably in the medial layer of human common iliac arteries. This paper aims to provide a possible explanation for this intriguing phenomenon. An invariant-based constitutive model is utilized to characterize the mechanical behaviour of tissues. We then use three different hypotheses to determine the 'optimal fibre angle' in an iliac artery model. All three hypotheses lead to the same result that the optimal fibre angle in the medial layer of the iliac artery is close to the circumferential direction. The axial pre-stretch, in particular, is found to play an essential role in determining the optimal fibre angle.
authors.affiliation: School of Mathematics and Statistics, University of Glasgow, 15 University Gardens, Glasgow G12 8QW, UK.
authors.forename: Nan
authors.initials: N
authors.lastname: Qi
authors.affiliation: School of Mathematics and Statistics, University of Glasgow, 15 University Gardens, Glasgow G12 8QW, UK.
authors.forename: Hao
authors.initials: H
authors.lastname: Gao
authors.affiliation: School of Mathematics and Statistics, University of Glasgow, 15 University Gardens, Glasgow G12 8QW, UK.
authors.forename: Raymond W
authors.initials: RW
authors.lastname: Ogden
authors.affiliation: School of Mathematics and Statistics, University of Glasgow, 15 University Gardens, Glasgow G12 8QW, UK.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Hill
authors.affiliation: Institute of Biomechanics, Graz University of Technology, Kronesgasse 5-I, 8010 Graz, Austria.
authors.forename: Gerhard A
authors.initials: GA
authors.lastname: Holzapfel
authors.affiliation: Department of Mechanical Engineering, The University of Texas at San Antonio, San Antonio, TX 78249, USA.
authors.forename: Hai-Chao
authors.initials: HC
authors.lastname: Han
authors.affiliation: School of Mathematics and Statistics, University of Glasgow, 15 University Gardens, Glasgow G12 8QW, UK. Electronic address: xiaoyu.luo@glasgow.ac.uk.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Luo
mesh_terms: D003094:Collagen / Q000737:chemistry*; D004734:Energy Metabolism; D006801:Humans; D007083:Iliac Artery / Q000033:anatomy & histology* / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D008953:Models, Anatomic; D013314:Stress, Mechanical; D066253:Vascular Remodeling
chemical_list: D003094:Collagen
keywords: Collagen fibre; Constitutive law; Fibre orientation; Iliac bifurcation; Pre-stretch; Remodelling; Residual stress; Total energy