A Constitutive Model of Ligaments and Tendons Accounting for Fiber-Matrix Interaction
Abstract:In this study, a new constitutive model is developed
to describe the hyperelastic behavior of collagenous tissues with a
parallel arrangement of collagen fibers such as ligaments and tendons.
The model is formulated using a continuum approach incorporating
the structural changes of the main tissue components: collagen fibers,
proteoglycan-rich matrix and fiber-matrix interaction. The mechanical
contribution of the interaction between the fibers and the matrix
is simply expressed by a coupling term. The structural change
of the collagen fibers is incorporated in the constitutive model to
describe the activation of the fibers under tissue straining. Finally, the
constitutive model can easily describe the stress-stretch nonlinearity
which occurs when a ligament/tendon is axially stretched. This
study shows that the interaction between the fibers and the matrix
contributes to the mechanical tissue response. Therefore, the model
may lead to a better understanding of the physiological mechanisms
of ligaments and tendons under axial loading.
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