Dynamic biphasic poroviscoelastic model simulation of hydrated soft tissues and its potential applications for brain impact study

摘要

Traumatic brain injury (TBI) frequently results from various situations that cause blunt impact to the head. Extensive studies have been conducted to understand the mechanical behavior and the injury mechanism of brain. However, such knowledge is still very limited. The main difficulty lies in the complexity of both material properties and geometry of brain tissue, for which the finite element method (FEM) has been proved to be effective. While the geometric modeling of brain has significantly improved with the advancement of imaging techniques, accurate material modeling remains elusive. Traditionally, the brain has been modeled as a Kelvin viscoelastic solid, which does not capture the complete viscoelasticity of the tissue. Brain is a hydrated soft tissue, which consists of about 78% water, 10-12% phospholipids, 8% protein, and small amounts of carbohydrates, inorganic salts, and soluble organic substances. The viscoelastic behavior of brain tissue thus depends on the mechanical properties of each constituent as well as interactions between constituents. Such viscoelastic behavior of multi-constituent material has been well characterized by the biphasic poroviscoelastic (BPVE) model, which represents the tissue's viscoelasticity as a combination of the fluid flow-dependent and fluid flow-independent mechanisms. Therefore, the objective of the current study was to investigate the applicability of the BPVE dynamic finite element model to brain impact simulation.