Brain Material Properties and Integration of Arachnoid Complex for Biofidelic Impact Response for Human Head Finite...

Area of Science:

• Biomechanics
• Computational Mechanics
• Neuroscience

Background:

• Current finite element head models simplify brain tissue properties and omit complex anatomical structures like the arachnoid complex.
• Existing models often use linear viscoelasticity or optimized material properties for specific impact scenarios, limiting their predictive accuracy.
• These simplifications hinder the detailed study of brain-related injuries.

Purpose of the Study:

• To develop an enhanced finite element head model with improved accuracy for simulating brain injury.
• To incorporate a hyper-viscoelastic constitutive model for brain tissue based on experimental data.
• To include a detailed representation of the arachnoid trabeculae to improve the brain-skull interface.

Main Methods:

• Material parameters for a hyper-viscoelastic model were fitted using recent experimental data from four brain regions across three strain rates and three loading modes (tension, compression, shear).
• The developed material model was implemented into a detailed head finite element model.
• A detailed arachnoid trabeculae structure with experimentally derived mechanical properties was integrated.
• The enhanced model's biofidelity was assessed by simulating 11 ex vivo head impact scenarios and comparing results with experimental data.

Main Results:

• The hyper-viscoelastic material model accurately captured brain tissue mechanical properties under various loading conditions and strain rates.
• The enhanced head model demonstrated high biofidelity across all simulated impact scenarios.
• The improved brain-skull interface, due to the inclusion of arachnoid trabeculae, significantly contributed to the model's accuracy.

Conclusions:

• The enhanced finite element head model provides improved predictive capabilities for head impacts.
• Utilizing tissue-level data for material properties and detailed anatomical structures enhances model realism.
• This advanced model is well-positioned for future investigations into head injury mechanisms and tissue damage.