Mesh considerations for finite element blast modelling in biomechanics

Area of Science:

• Computational mechanics
• Biomechanical engineering
• Fluid-structure interaction modeling

Background:

• Finite element (FE) modeling is crucial for understanding human responses to blast events.
• Blast modeling presents challenges due to complex fluid-structure interactions (FSIs) and high-frequency loading.
• Optimizing FE mesh design is essential for accurate blast simulation results.

Purpose of the Study:

• To investigate the impact of mesh design on finite element (FE) blast modeling.
• To compare the performance of tetrahedral and hexahedral elements in blast simulations.
• To determine the influence of element size and type on predicted pressures and stresses.

Main Methods:

• A sphere within a shock tube was modeled using finite element analysis.
• Meshes with varying element sizes were created using both tetrahedral and hexahedral elements.
• Fluid-structure interactions (FSIs) and acceleration responses were analyzed.
• Deviatoric stress and pressure responses were evaluated based on mesh parameters.

Main Results:

• Fluid-structure interaction (FSI) consistency was observed for sphere-to-fluid element ratios from 0.25 to 4.
• Acceleration responses were similar between tetrahedral and hexahedral elements (R² = 0.997).
• Tetrahedral elements exhibited volatility under shock loading, predicting higher pressures and stresses than hexahedral elements.
• Deviatoric stress was dependent on sphere mesh size (p < 0.001), and pressure was dependent on shock tube mesh size (p < 0.001).

Conclusions:

• Mesh design significantly influences the accuracy of blast modeling.
• Hexahedral elements provide more stable and accurate predictions compared to tetrahedral elements in blast simulations.
• Mesh sensitivity analysis is a critical step for reliable finite element (FE) blast models.