Modelling the mechanical properties of human skin: towards a 3D discrete fibre model

In this study a three-dimensional discrete fibre model was developed to provide insights into the important structure-function relationship in skin tissue. A structural approach determines the macroscopic mechanical response of the tissue from its underlying structural components. A network of collagen fibres was embedded into a tissue block of tissue. A family of fibres with varying orientations was centred in the block. Each fibre was assumed to be undulated with the ability to resist load only when completely straightened. Statistical distributions were used to determine fibre orientations and extent of undulation. Other model parameters include fibre density, fibre thickness and fibre stiffness. A force balance was performed to compute the macroscopic mechanical response when the tissue block was subjected to simple deformation modes. Force-stretch plots were generated for two simple modes of deformation under different structural scenarios. The nonlinear mechanical response was largely due to varying degrees of fibre undulation. The extension of this work is to establish the link between discrete-level models and continuum mechanical models.