Simulation of Brain Response to Noncontact Impacts Using Coupled Eulerian-Lagrangian Method

Area of Science:

• Biomechanics
• Computational Mechanics
• Neuroscience

Background:

• Finite element (FE) methods are crucial for understanding brain tissue mechanics during impacts.
• Large deformations in cerebrospinal fluid (CSF) regions pose challenges for traditional FE models.
• Biofidelic modeling requires accurate simulation of brain-skull interactions.

Purpose of the Study:

• To implement a coupled Eulerian-Lagrangian (CEL) formulation for head impact simulations.
• To overcome mesh distortion issues in simulating cerebrospinal fluid (CSF) dynamics.
• To provide a biofidelic model for brain-skull interaction analysis.

Main Methods:

• A head system FE model was created using a transverse section of the human brain.
• Cerebrospinal fluid (CSF) was modeled using Eulerian elements.
• Spring connectors simulated the pia-arachnoid connection; CEL formulation addressed large deformations.
• Model validation was performed against experimental data.

Main Results:

• The CEL formulation accurately captured brain tissue dynamics under noncontact impacts.
• Higher contrecoup injury likelihood was observed compared to coup injury during sudden brain-skull motion.
• CSF accumulation in the ventricle system was identified under large relative brain-skull motion.
• Rotational velocities in addition to translational impacts created diffuse high strain areas and temporal lobe susceptibility.

Conclusions:

• The CEL FE model provides a validated, biofidelic approach for head impact simulation.
• Rotational head motion significantly increases the risk of diffuse brain injury and specific injuries like cerebral contusions.
• Understanding CSF dynamics is critical for predicting brain injury severity and location.