Affiliations: Department of Mechanical and Mechatronic Engineering, University of Sydney, Australia
Note: [] Address for correspondence: Dr. Lynne Bilston, Department of Mechanical and Mechatronic Engineering, Building J07, University of Sydney, NSW 2006, Australia. Tel: +61 2 9351 2344; Fax: +61 2 9351 7060; E‐mail: [email protected].
Abstract: In this paper, some experimental measurements of the behaviour of bovine brain tissue under large shear strains in vitro are reported, and a constitutive model which is consistent with the data is developed. It was determined that brain tissue is not strain‐time separable, showing slower relaxation at higher strains, and that the stresses in shear are not linear with increasing shear strain. The new constitutive model is a differential model, including both an “elastic” term, of the Mooney type and a nonlinear viscoelastic term. The latter allows for the change in relaxation behaviour with strain, by modifying an upper convected multimode Maxwell model with a damping function. The model shows good agreement with the experimental shear results and could be used to describe other types of data.
