Development and Mechanical Analysis of Human Liver Model During Impact

Area of Science:

• Biomechanics
• Computational modeling
• Trauma research

Background:

• Traffic trauma poses severe risks, with liver injury being a significant concern.
• Accurate finite element models (FEM) of the liver are crucial for enhancing the biofidelity and validity of automotive crash simulations.
• Understanding liver mechanical responses during impact is essential for injury prevention.

Purpose of the Study:

• To develop and validate accurate human liver finite element models for crash simulations.
• To compare the accuracy of different modeling methods (tetrahedral vs. hexahedral elements) for liver FEM.
• To investigate the influence of the liver capsule on mechanical responses during simulated impacts.

Main Methods:

• Construction of 12 human liver FEM from high-resolution CT data of a 50th percentile male subject.
• Inclusion of key liver structures: left lobe, right lobe, capsule, parenchyma, and falciform ligament.
• Validation through simulations based on the Nava et al. experiment to compare modeling method accuracy.

Main Results:

• Hexahedral (hex) element models demonstrated higher accuracy compared to tetrahedral (tetra) element models.
• Tetra models exhibited greater deviation due to a stiffer algorithm.
• Hex models showed sensitivity to element size.
• The presence of the liver capsule significantly reduced internal tissue pressure, indicating its protective effect.
• Shell elements proved more suitable for accurately modeling the liver capsule.

Conclusions:

• The study successfully developed and validated human liver FEM, offering improved biofidelity for crash simulations.
• Hex models are recommended over tetra models for liver FEM due to superior accuracy and stability.
• The liver capsule plays a critical role in mitigating mechanical stress, and shell elements are optimal for its representation in FEM.