Further Insight into the Depth-Dependent Microstructural Response of Cartilage to Compression Using a Channel Indentation Technique

Figure 12

The initial stress relaxation response, or viscous response, is illustrated here. Going from (a) to (b), the initial linear elastic resistance to compression is a combination of the deformation in the spring component and an instantaneous hydrostatic pressure in the dashpot. Going from (b) to (c) the stress then decays, with fluid flow through permeable walls (d), until the quasi-equilibrium state “𝑃” is attained following reduction in matrix permeability. This equilibrium stress state 𝑃 is a transition before the next stress relaxation phase takes place (see Figure 13).