Table 1.

Specific boundary conditions of the finite element analysis^a

	At the AF edge	At the endplate(i.e., z=h0)
Oxygen/Lactate	c+ = c− =0.15 M, co2= =5.8 kPa, clactate= 0.9 mM.	$\{\begin{array}{ll}{J}_z^{+}=J_z^{-}=J_z^{O_2}=J_z^{\mathit{lactate}}=0\text{ (molar solute flux)}\hfill & \text{if impermeable}\hfill \\ c^{+}=c^{-}=0.15\text{M},c^{O_2}=5.1\text{kPa},c^{\mathit{lactate}}=0.8\text{mM}\hfill & \text{if permeable}\hfill \end{array}$
Solid Matrix	σr = σrz = 0	$\begin{array}{l}{u}_z^b=\{\begin{array}{ll}0\hfill & \text{when without compression}\hfill \\ -u_0\hfill & \text{when with static compression}\hfill \\ -u_0-u_{1}sin(2\pi ft)\hfill & \text{when with dynamic compression}\hfill \end{array}\\ u_r=0\end{array}$

^aThe rest of boundary conditions for stress and strain of solid matrix, fluid pressure, and fluxes of water and solute for the 2-D axisymmetric case of unconfined compression were described in our previous study (Huang and Gu, 2007).

^bu₀ =10% of disc height (i.e., 0.1h₀), f=0.1 or 0.01Hz, and u₁ =2.5% or 5% of disc height (i.e., 0.025h₀ or 0.05h₀).