A Composite Micromechanical Model for Connective Tissues: Part II—Application to Rat Tail Tendon and Joint Capsule

Abstract

A micromechanical model of fibrous soft tissue has been developed which predicts upper and lower bounds on mechanical properties based on the structure and properties of tissue components by Ault and Hoffman [3, 4]. In this paper, two types of biological tissue are modeled and the results compared to experimental test data. The highly organized structure of rat tail tendon is modeled using the upper bound aggregation rule which predicts uniform strain behavior in the composite material. This model fits the experimental data and results in a correlation coefficient of 0.98. Applied to cat knee joint capsule, the lower bound aggregation rule of the model correlates with the data and predicts uniform stress within this more loosely organized tissue structure. These studies show that the nature of the interactions between the components in tissue differs depending upon its structure and that the biomechanical model is capable of analyzing such differences in structure.

Equal and local-load-sharing micromechanical models for collagens: Quantitative comparisons in response of non-diabetic and diabetic rat tissue

“…An interesting extension of the current work would be the application of these methods of Refs. [63,64] to problems of biological relevance, especially in the fields of disease modeling and tissue engineering.…”

Modelling approaches for evaluating multiscale tendon mechanics

“…In this formulation, tendon is modelled by embedding straight or wavy collagen fibrils/fibres in a surrounding non-fibrillar matrix, mainly composed of PGs [91][92][93]. The strain energy function for the composite tendon can then be simply decomposed into the elastic strain energy stored within reinforcing fibres and the isochoric energy of the deformation in the matrix [80,94].…”

“…Using a different approach, a dissipative theory was applied to account for temporary reversible interfibrillar bridges between collagenous and non-collagenous components in interpreting tendon softening and non-recoverable strains in cyclic mechanical testing [76,115]. In this case, the time-dependent strain energy function was taken as the sum of the viscoelastic strain energy functions for the anisotropic non-fibrillar matrix and collagen fibrils [91,115]. The breaking and reformation of active regions in both matrix and fibrillar components were represented by the transient network theory [76] and contributed to the rsfs.royalsocietypublishing.org Interface Focus 6: 20150044 model's constitutive equation [76,114].…”

A transversely isotropic viscohyperelastic material

“…As these curves were obtained for tensile tests in the fiber direction and by assuming isotropy of the material, it was necessary to relate the response of the matrix when no fiber contributes. This was done by giving the estimated value of 1 MPa to the compliant solid matrix, also called ground substance (Ault and Hoffman, 1992;Limbert, 2001;Limbert et al, 2004;Limbert and Taylor, 2001a). The graphic results of the identification is represented in Fig.…”