Investigation of the mechanical behavior of kangaroo humeral head cartilage tissue by a porohyperelastic model based on the strain-rate-dependent permeability

Abstract

Solid-interstitial fluid interaction, which depends on tissue permeability, is significant to the strain-rate-dependent mechanical behavior of humeral head (shoulder) cartilage. Due to anatomical and biomechanical similarities to that of the human shoulder, kangaroos present a suitable animal model. Therefore, indentation experiments were conducted on kangaroo shoulder cartilage tissues from low (10(-4)/s) to moderately high (10(-2)/s) strain-rates. A porohyperelastic model was developed based on the experimental characterization; and a permeability function that takes into account the effect of strain-rate on permeability (strain-rate-dependent permeability) was introduced into the model to investigate the effect of rate-dependent fluid flow on tissue response. The prediction of the model with the strain-rate-dependent permeability was compared with those of the models using constant permeability and strain-dependent permeability. Compared to the model with constant permeability, the models with strain-dependent and strain-rate-dependent permeability were able to better capture the experimental variation at all strain-rates (p < 0.05). Significant differences were not identified between models with strain-dependent and strain-rate-dependent permeability at strain-rate of 5 × 10(-3)/s (p = 0.179). However, at strain-rate of 10(-2)/s, the model with strain-rate-dependent permeability was significantly better at capturing the experimental results (p < 0.005). The findings thus revealed the significance of rate-dependent fluid flow on tissue behavior at large strain-rates, which provides insights into the mechanical deformation mechanisms of cartilage tissues.

Effect of Substrate Stiffness on Mechanical Coupling and Force Propagation at the Infarct Boundary

“…The porohyperelastic (PHE) model, which was developed based on the Consolidation Theory (33,(39)(40)(41), has been demonstrated as a powerful and suitable model for studying cell biomechanics (33,42). This theory was an extension of the poroelastic theory (43) to characterize and predict large deformations and nonlinear responses in structures under loading.…”

Physical mechanisms underlying the strain-rate-dependent mechanical behavior of kangaroo shoulder cartilage

“…The behavior of the kangaroo shoulder cartilage can be represented by 2-term reduced polynomial hyperelastic function. 38 In the present study, the relationship between force (F) and indentation depth (d) given by Lin et al 39 for the 2-term reduced polynomial hyperelastic model was modified to account for indenter geometry and finite sample thickness. Other methodologies, such as by Zhang et al, 40 can also be applied to obtain force-indentation relationship for hyperelastic materials.…”