Modelling brain tissue elasticity with the Ogden model and an alternative family of constitutive models†

The Ogden model is often considered as a standard model in the literature for application to the deformation of brain tissue. Here, we show that, in some of those applications, the use of the Ogden model leads to the non-convexity of the strain-energy function and mis-prediction of the correct concavity of the experimental stress-stretch curves over a range of the deformation domain. By contrast, we propose a family of models which provides a favourable fit to the considered datasets while remaining free from the highlighted shortcomings of the Ogden model. While, as we discuss, those shortcomings might be due to the artefacts of the testing protocols, the proposed family of models proves impervious to such artefacts.This article is part of the theme issue 'The Ogden model of rubber mechanics: Fifty years of impact on nonlinear elasticity'.

Automated summary

The Ogden model is often used in the study of brain tissue deformation, but it has been found to have limitations in certain applications. This study proposes a family of models that provide better fit to experimental data and are not affected by testing artefacts. The findings suggest the need for further refinement of deformation models for brain tissue.