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](references/api-quick-ref.md) - [Materials Database](references/materials-database.md) - [Troubleshooting Guide](references/troubleshooting.md)