abaqus-material

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:

• API Quick Reference
• Materials Database
• Troubleshooting Guide