Shear-deformation based continuum-damage constitutive modeling of brain tissue

Traumatic brain injury (TBI) isa leading cause of death in the United States. Depending on the severity of injury, complications such as memory loss and emotional changes are common. While the exact mechanisms are still unclear, these cognitive deficiencies are thought to arise from microstructural damages to the brain tissue, such as in diffuse-axonal injury where neuron fibers are sheared. Constitutive models can predict such damage at a microstructural level and allow for insight into the mechanisms of injury initiating at lower length scales. In this study, we developed a continuum damage model of brain tissue that is validated by experimental quasi-static stress-strain tests in tension, compression, and shear. The present work shows that damage is most present in the shear stress state, making the tissue suitable for damage modeling via shear interaction terms. Using this model, new insights into microstructural breakdown due to shear stresses and strains can be gained by application to simulations. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Traumatic brain injury is a major cause of death in the United States, leading to cognitive deficiencies due to microstructural damages to brain tissue, especially in diffuse-axonal injury where neuron fibers are sheared. Constitutive models can predict and provide insight into such damage at a microstructural level, with research showing that most damage occurs in the shear stress state.