Mesh Generation for FEA

Definition & Context

Mesh generation is the discretisation of a CAD body into elements for FEA/CFD. The dominant 3-D element types are tetrahedra (fill arbitrary geometry automatically, ideal for solid stress), hexahedra (more accurate per DOF but hard to auto-generate on complex shapes), and prisms/pyramids used as transition and boundary-layer elements.

Mesh quality is measured by metrics such as aspect ratio, skewness, Jacobian, and orthogonal quality. Local controls — sizing, curvature refinement, inflation/boundary layers for CFD, and mapped meshing on prismatic regions — let the analyst put elements where gradients are steep and coarsen elsewhere to control solve time.

Why It Matters

The mesh is the single biggest driver of both accuracy and runtime in simulation. A poorly conditioned element (negative Jacobian, high skew) can stall the solver or produce garbage stresses, while an unnecessarily fine mesh wastes hours of compute — so mesh strategy is a core CAE skill.

The efficient approach is a graded mesh, not a uniformly fine one: refine locally where gradients are steep (fillets, contacts, stress raisers) and coarsen in bulk regions, using element order deliberately — second-order (parabolic) elements capture bending far better per node, so linear tetrahedra should be avoided for stress. CFD adds its own requirement: near-wall inflation/boundary-layer layers sized to the target y+ for the chosen turbulence model, because the wall treatment, not the core mesh, usually decides whether drag and heat-transfer predictions are believable.

Best Practices

• Refine locally at fillets, holes, and load paths; coarsen in low-gradient bulk regions to keep the model affordable.
• For CFD, add prism/inflation layers at walls and target the required y+ for your turbulence model.
• Use curvature-based sizing so curved surfaces are faceted finely enough to represent geometry.
• Check element quality metrics (skewness < 0.9, orthogonal quality > 0.1) before solving.
• Prefer hex or sweep meshes on prismatic/rotational bodies where they fit — fewer elements for the same accuracy.

Common Pitfalls

• Meshing dirty geometry (slivers, gaps, tiny faces) — always defeature and heal first.
• One global element size that is fine everywhere, blowing up DOF count and solve time.
• Ignoring the boundary layer in CFD, which ruins wall shear and heat-transfer predictions.
• Leaving highly skewed or negative-Jacobian elements that cause solver divergence.

Sources & Further Reading

• ANSYS — Meshing user guide
• NAFEMS — Why do meshes matter

Related Concepts

• Finite Element Analysis — what the structural mesh feeds
• CFD Fundamentals — where boundary-layer meshing is critical
• Contact Analysis — mesh matching at contact interfaces
• Thermal Analysis — meshing for conduction/CHT

Enterprise Production Implementation & GstarCAD 2027 Workflow

• Database Serialization & Binary Fidelity: Ensure all entities and symbol table records associated with Mesh Generation for FEA are authored on standardized ISO 13567 layers rather than Layer 0 or Defpoints, and verify lossless round-trip persistence in native DWG (AC1032) format.