A Constitutive Model for the Annulus of Human Intervertebral Disc: Implications for Developing a Degeneration Model and Its Influence on Lumbar Spine Functioning

Table 2

Material properties used for the normal and degenerated AF [4, 15, 17, 26, 39, 43, 44, 47].

	Normal	Degenerated
Biphasic material parameters
𝑐𝐹,0 [meq/mm^3]	1.8×10^−4	0.9×10^−4
𝑘0 [m^4/Ns]	1.924×10^−16	1.5×10^−16
𝑛𝑓,0	0.75	0.7
𝑒 (void ratio)	3.0	2.33
Elastic material parameters
𝐶10 [MPa]	0.1	0.45
𝐶20 [MPa]	2.5
𝐷 [MPa^−1]	4.8
𝐾1 [MPa]	1.8
𝐾2	11.0