The effect of fluid pressure in porous сomposites: a mathematical model applied to the optic nerve

Abstract

The optic nerve, essential for vision, consists of nerve fibers immersed in biofluid, which is critical for the efficient transmission of visual signals. However, the response of the optic nerve to physiological loads is not yet fully understood. Structurally, the optic nerve can be modeled as a cylindrical composite with an outer elastic sheath and an inner porous core saturated with biofluid. Existing computational and material models fall short in capturing the full complexity of this tissue, particularly the role of biofluid as a load-bearing component. To address this gap, we developed an analytical model of a cylindrical composite with a poroelastic core and an elastic sheath under axial loading. Our analysis focused on the influence of the composite’s geometry and material properties on the stress distribution within the structure. We identified physiologically relevant conditions under which the sheath and biofluid bear the majority of the applied stress, surpassing the load carried by the solid components of the core. The model predicts that fluid pressure can constitute up to one-third of the applied stress. Additionally, we explored how variations in sheath thickness and core compressibility influence the stress-strain response, offering insights into the mechanical behavior of the optic nerve. This study provides a framework for comparing material parameters across healthy, aged, and diseased nerves, as well as biomaterials. Moreover, our model offers a foundation for the design of materials inspired by the optic nerve’s unique structure.

Speaker

Denis Kucherenko
Virginia Polytechnic Institute and State University
USA

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