Table 2:

Biaxial experimental protocols. ${\lambda }_x$ and ${\lambda }_y$ represent the stretches imposed in the $x$ and $y$ directions and ${\sigma }_z$ is the stress in the $z$ direction. The parameter $\lambda$ is monotonically increased during the experiments to stretch the tissue. The last component of the deformation gradient is directly obtained from the incompressible constraint, while the vanishing normal stress is imposed as the necessary boundary condition to solve for the pressure $p$.

Loading	${\lambda }_{xx}$	${\lambda }_{yy}$	${\sigma }_{zz}$
Off-x	$\sqrt{\lambda }$	$\lambda$	0
Off-y	$\lambda$	$\sqrt{\lambda }$	0
Equibiaxial	$\lambda$	$\lambda$	0
Strip-x	$\lambda$	1	0
Strip-y	1	$\lambda$	0