The experimental data from nanomechanical testing of collagen type I fibres will be used to validate theoretical constitutive models of annulus fibrosus function. Three models will be evaluated: i) the solid-phase viscoelastic behaviour of general materials, ii) the solid-phase viscoelastic behaviour of soft tissues, iii) the flow of water through the porous-permeable solid matrix of cartilage. Each model will be experimentally evaluated at the nano- and micro-scales and will aid in the formulation of a theoretical framework for numerical models used in a multiscale modelling approach to whole-disc behaviour.
