abaqus-thermal-analysis

# Abaqus Thermal Analysis Workflow Heat transfer analysis for steady-state or transient temperature distribution. Use when user needs temperature field without mechanical stress. ## When to Use This Skill **Route here when user mentions:** - "Heat transfer analysis", "temperature distribution" - "How hot will it get?", "thermal analysis" - "Conduction", "convection", "radiation" - "Heat sink design", "cooling analysis" - "Steady-state temperature", "transient heating/cooling" **Route elsewhere:** - Thermal stress (temperature causing deformation) → `/abaqus-coupled-analysis` - Just stress analysis → `/abaqus-static-analysis` - Temperature as initial condition only → `/abaqus-field` ## Prerequisites Before thermal analysis: 1. Geometry defined 2. Thermal conductivity (k) - required for all thermal analysis 3. For transient: also need density (ρ) and specific heat (cp) ## Workflow: Thermal Analysis ### Step 1: Understand User's Goal Ask if unclear: - **Steady-state or transient?** Final equilibrium vs temperature over time? - **Boundary temperatures?** Fixed temperature surfaces? - **Convection?** Film coefficient and ambient temperature? - **Heat sources?** Applied heat flux or internal heat generation? ### Step 2: Choose Analysis Type | User Wants | Analysis Type | |------------|---------------| | Final equilibrium temperature | STEADY_STATE | | Temperature vs time history | TRANSIENT | | Cool-down or heat-up time | TRANSIENT | | Just the end result | STEADY_STATE | **Decision rule:** Use steady-state unless user needs temperature history or time-dependent behavior. ### Step 3: Define Thermal Material Properties | Property | Required For | Units (SI-mm) | |----------|--------------|---------------| | Conductivity (k) | All thermal | mW/(mm·K) | | Specific heat (cp) | Transient | mJ/(tonne·K) | | Density (ρ) | Transient | tonne/mm³ | **Common materials (SI-mm units):** | Material | k | cp | ρ | |----------|---|----|----| | Steel | 50 | 5.0e11 | 7.85e-9 | | Aluminum | 167 | 9.0e11 | 2.70e-9 | | Copper | 385 | 3.85e11 | 8.96e-9 | ### Step 4: Apply Thermal Boundary Conditions | BC Type | Use For | Required Inputs | |---------|---------|-----------------| | TemperatureBC | Fixed temperature surface | Temperature value | | FilmCondition | Convection to ambient | Film coeff, sink temp | | SurfaceHeatFlux | Heat input | Flux magnitude (mW/mm²) | | RadiationToAmbient | Radiation cooling | Emissivity, ambient temp | | BodyHeatFlux | Internal heat generation | Volumetric heat rate | **Minimum requirement:** At least one temperature BC or heat flux boundary. ### Step 5: Create Heat Transfer Step | Parameter | Steady-State | Transient | |-----------|--------------|-----------| | response | STEADY_STATE | TRANSIENT | | timePeriod | 1.0 (arbitrary) | Actual duration (s) | | initialInc | - | Start increment | | maxInc | - | Largest allowed increment | | deltmx | - | Max temp change per increment | ### Step 6: Mesh with Heat Transfer Elements | Element | Use | |---------|-----| | DC3D8 | Standard 8-node hex (recommended) | | DC3D4 | 4-node tet (for complex geometry) | | DC3D20 | 20-node hex (high accuracy) | **Note:** Heat transfer elements (DC*) are different from structural elements (C3D*). ### Step 7: Run Analysis and Extract Results Request these field outputs: - **NT** - Nodal temperature - **HFL** - Heat flux vector - **RFL** - Reaction heat flux - **HFLM** - Heat flux magnitude ## Validation Checklist After analysis, verify: - [ ] Temperature range is physically reasonable - [ ] Heat balance: flux in ≈ flux out (steady-state) - [ ] No unexpected hot/cold spots - [ ] Transient: temperature stabilizes by end of analysis ## Troubleshooting | Problem | Likely Cause | Solution | |---------|--------------|----------| | Temperature oscillation | Large increments in transient | Reduce maxInc or deltmx | | Non-physical temperature | Unit mismatch | Verify k, cp, ρ units | | No heat flow | Missing BC or bad region | Check boundary conditions | | Negative temperature (Kelvin) | Bad setup | Review initial conditions | ## Related Skills - `/abaqus-coupled-analysis` - Thermal + structural (thermomechanical) - `/abaqus-material` - Thermal material properties - `/abaqus-field` - Initial temperature fields ## Code Patterns For API syntax and code examples, see: - [API Quick Reference](references/api-quick-ref.md) - [Common Patterns](references/common-patterns.md) - [Troubleshooting Guide](references/troubleshooting.md)