An uncoupled directional damage model for fibred biological soft tissues. Formulation and computational aspects

In this paper we present a fully three‐dimensional finite‐strain damage model for fibrous soft tissue. Continuum damage mechanics is used to describe the softening behaviour of soft tissues under large deformation. The structural model is formulated using the concept of internal variables that provides a very general description of materials involving irreversible effects. We considered the internal variables associated to damage to correspond to separated contributions of the matrix and fibres. In order to show clearly the performance of the constitutive model, we present 3D simulations of the behaviour of the human medial collateral ligament and of a coronary artery. Results show that the model is able to capture the typical stress–strain behaviour observed in fibrous soft tissues and seems to confirm the soundness of the proposed formulation.