Abaqus Material Skill

Define material properties and assign sections to parts. This skill handles elastic, plastic, thermal, and composite material definitions.

When to Use This Skill

Route here when user mentions:

"steel", "aluminum", "titanium", or other material names
"Young's modulus", "elastic", "Poisson's ratio"
"plastic", "yielding", "hardening"
"density" for gravity/dynamics
"thermal conductivity", "expansion"
"assign material to part"

Route elsewhere:

Contact properties (friction, damping) → /abaqus-interaction
Optimization material interpolation → /abaqus-optimization
Temperature boundary conditions → /abaqus-field

Key Decisions

1. What Properties Are Needed?

| Analysis Type | Required | Optional | |--------------|----------|----------| | Static stress | E, ν | - | | Static with gravity | E, ν, ρ | - | | Yielding/plastic | E, ν, σy | ρ | | Modal/frequency | E, ν, ρ | - | | Dynamic explicit | E, ν, ρ | Plasticity | | Thermal stress | E, ν, α | k, cp | | Heat transfer only | k | cp, ρ |

Key insight: Density (ρ) is required whenever inertia matters - modal analysis, dynamics, gravity loads.

2. Common Material Values

| Material | E (MPa) | ν | ρ (t/mm³) | σy (MPa) | |----------|---------|---|-----------|----------| | Steel (mild) | 210000 | 0.30 | 7.85e-9 | 250 | | Steel (high-strength) | 210000 | 0.30 | 7.85e-9 | 550 | | Stainless 304 | 193000 | 0.29 | 8.00e-9 | 215 | | Aluminum 6061-T6 | 68900 | 0.33 | 2.70e-9 | 276 | | Aluminum 7075-T6 | 71700 | 0.33 | 2.81e-9 | 503 | | Titanium Ti-6Al-4V | 113800 | 0.34 | 4.43e-9 | 880 |

Unit system: mm-tonne-s-N-MPa (consistent SI)

3. Section Type Selection

| Geometry Type | Section Type | When to Use | |--------------|--------------|-------------| | 3D solid (hex/tet) | HomogeneousSolidSection | Most FEA models | | Thin walls (t/L < 0.1) | HomogeneousShellSection | Plates, sheet metal | | Slender members (L/d > 10) | BeamSection | Frames, trusses | | Layered composites | CompositeShellSection | Carbon fiber, laminates |

What to Ask User

If unclear, ask:

What material? Steel, aluminum, custom values?
Need plasticity? Will stresses exceed yield?
Need density? Is this for dynamics, modal, or gravity?
Temperature effects? Thermal expansion, temperature-dependent properties?

Workflow

Step 1: Create Material

Create a material object with a descriptive name.

Step 2: Add Required Properties

At minimum, add elastic properties (E, ν). Add density if analysis requires it.

Step 3: Add Optional Properties

Add plasticity, thermal, or other properties as needed.

Step 4: Create Section

Create appropriate section type (solid, shell, beam) referencing the material.

Step 5: Assign Section to Part

Assign section to all cells/faces that need this material.

Validation Checklist

Before running analysis, verify:

[ ] E > 0 (positive stiffness)
[ ] -1 < ν < 0.5 (ν = 0.5 causes numerical issues)
[ ] ρ > 0 if required for analysis type
[ ] Plastic table starts at zero plastic strain
[ ] Section assigned to ALL cells that need it

Troubleshooting

| Problem | Likely Cause | Solution | |---------|--------------|----------| | "Material has no density" | Analysis requires density | Add density property | | "Negative eigenvalue in stiffness" | Invalid Poisson's ratio | Ensure -1 < ν < 0.5 | | "Section not assigned" | Missing assignment call | Assign section to region | | "Material X not found" | Typo in material name | Check spelling matches | | "Region has no mesh" | Mesh order issue | Mesh after section assignment |

Code Patterns

For actual API syntax and code examples, see: