Human liver finite element model validation using compressive and tensile experimental data - biomed 2013

Area of Science:

• Biomechanics
• Computational modeling
• Trauma research

Background:

• Motor vehicle crashes frequently cause blunt abdominal trauma, necessitating reliable injury assessment tools.
• Finite element models (FEM) are vital for injury assessment, but their accuracy relies on precise material models.
• A hyperelastic and viscoelastic liver material model was recently proposed by Samur et al.

Purpose of the Study:

• To compare a computational liver model's predictions with experimental biomechanical data.
• To evaluate the accuracy of a proposed hyperelastic and viscoelastic liver material model.
• To assess the model's suitability for finite element analysis in trauma research.

Main Methods:

• Liver tissue samples were simulated using the finite element method with four different mesh types (fine/coarse hexahedral/tetrahedral).
• Simulations subjected samples to uniaxial tension and compression at four strain rates (0.01 to 10 strain/sec).
• Model predictions were quantitatively compared against experimental data using the CORA software package.

Main Results:

• The computational model demonstrated higher accuracy in predicting the tensile response (CORA size error factor 0.66) compared to the compressive response (0.19).
• Fine tetrahedral, fine hexahedral, and coarse hexahedral meshes yielded similar predictive performance.
• The coarse tetrahedral mesh exhibited the poorest accuracy, with an 8.6% higher error factor than fine tetrahedral simulations.

Conclusions:

• The validated liver model shows promise for improving blunt abdominal trauma simulations in full-body FEM.
• The model captures viscoelastic behavior, though it currently under-predicts the experimentally observed loading rates.
• Further refinement of material models is recommended to enhance predictive accuracy for compressive loading conditions.