Colloqium: Victor Barocas, Multiscale Mechanics of Collagen Gels: Towards a Materials Science of Tissue

Abstract

Advances in biology, biochemistry, and microscopy have created a fabulous body of knowledge about how healthy and diseased tissues are put together. We know what proteins are there, what cells are there, in what quantity, and how they are arranged. In spite of this information, it is still difficult to predict the mechanical behavior of a soft tissue based on its composition and architecture, with failure behavior an even greater challenge than prefailure behavior. Towards the goal of creating predictive models of tissue mechanics, a two-scale mechanical model of collagen gel model systems has been developed, with the macroscopic (tissue) scale represented by continuous finite elements, and the microscopic (fiber network) scale represented by a network of nonlinear springs surrounding each integration point in the FE model. Thus, a closed-form constitutive law at the tissue scale is replaced by the network model, allowing incorporation of structural and compositional information. The model will be described briefly, followed by examples of prefailure behavior in an inhomogeneous anisotropic gel and failure behavior of an initially isotropic gel.

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