A Microstructural Study of Load Distribution in Cartilage: A Comparison of Stress Relaxation versus Creep Loading

Figure 12

(a) Initial compression of the cartilage tissue creates tension in the surface layer across the directly loaded and non-directly loaded (channel) regions. The matrix reaction is depicted by . (b) With small 1 MPa loads, a smaller compressive strain results, and holding the position following attainment of 1 MPa allows stress relaxation in the surface layer that creates a matrix shear, manifested by the shear bands shown as crisscross pattern. (c) With creep loading of the cartilage tissue, even with small loads, a relatively large compressive strain results from tissue consolidation at this fixed load. Fluid-pressure build-up and fluid displacement into the channel region cause matrix shear (shear bands) to form in the bulge region. (d) Matrix shear or shear bands and how they are formed are illustrated. Shear causes in-phase crimping (indicated with the dotted line) of the interconnected fibrillar matrix that is resolvable at the microscale (refer also to Figures 6(c) and 10).

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