Specimen specific parameter identification of ovine lumbar intervertebral discs: On the influence of fibre-matrix and fibre-fibre shear interactions

The present study investigated the influence of fibre-matrix and fibre-fibre shear interaction in ovine intervertebral discs. Parameter identifications were conducted based on in house experiments, in which moment-angle relations in flexion/extension, lateral bending and axial rotation were determined. A specimen-specific geometrical description of the numerical models could be attained with CT images and T2 maps. The parameter identification revealed that material laws with and without shear interaction were able to predict the mechanical tests equally well. However, when shear interaction was considered, the identified behaviour of the lamellae better matched published stress-strain relations in uniaxial and biaxial stress states.249