MODELLING OF ANISOTROPIC HYPERELASTIC MATERIALS WITH DAMAGE

The characteristic highly nonlinear biomechanics of soft tissues within their physiological range often involve degradation of the material properties. Some evidence shows that the stretch patterns induced in this (bio) structures lead to pathological conditions associated with the continuous degradation of the collagen fibres and ground substance of the material. In this work, a computational framework for modelling local anisotropic damage within non-linear geometrical considerations is proposed. Due to tissue and subject variability observed in the mechanical characterisation of these type of materials, we adopt a strongly-objective approach able to compute the material response for any functional form of the hyperelastic constitutive equations. The numerical examples of three-dimensional displacement-and force-driven boundary value problems describe the capability to use multiple material models within the same computational framework. Particularities in the behaviour of the considered material models and the implications of considering damage effects to represent the Mullins effect are discussed.