Figure 3.

Representation of the four families of collagen fibers in an arterial segment: fiber-reinforcement is defined in the undeformed configuration by the unit vectors M_αk=[0,sinα_k,cosα_k] where α_k is the fiber angle defined between the direction of the k^th family of collagen fibers and the axial direction of the artery. For axial fibers: α₁ = 0°; for circumferential fibers: α₂ = 90°; and for diagonal fibers: α₃ =α and α₄ = −α.