Fig. 4.

(a) Data points were generated on the surface of a unit sphere using matlab rand function. (b). Areal stretch after extension in x- and y-directions ($x\hspace{1em}=\hspace{1em}2X$, $y\hspace{1em}=\hspace{1em}3Y$, $z\hspace{1em}=\hspace{1em}Z$). Arrows show the direction of the major principal strain. (c) Main fiber direction $\mu$ (arrows) and normalized orientation index $\mathit{NOI}$ (contour plots) in un-deformed configuration. (d) Main fiber direction $\mu$ and normalized orientation index $\mathit{NOI}$ following axial extension (${\lambda }_x\hspace{1em}=\hspace{1em}1.5$).