diegosouzapw Abaqus Optimization Skill
This skill configures optimization tasks in Abaqus. It's the base module - for complete workflows, route to /abaqus-topology-optimization or /abaqus-shape-optimization.
When to Use This Skill
Route here when user mentions:
- "design response", "objective function", "optimization constraint"
- "SIMP penalty", "material interpolation"
- Low-level optimization setup (not complete workflows)
Route elsewhere:
- Complete topology optimization workflow →
/abaqus-topology-optimization - Complete shape optimization workflow →
/abaqus-shape-optimization - Running the optimization →
/abaqus-job
Prerequisites
Before optimization setup:
- ✅ Working static analysis that converges
- ✅ Appropriate mesh density
- ✅ Full Abaqus license with Tosca (not Learning Edition)
Workflow: Setting Up Optimization
Step 1: Understand User's Goal
Ask if unclear:
- What to optimize? Weight, stiffness, frequency, stress?
- What constraints? Volume limit, stress limit, displacement limit?
- Manufacturing? Casting (draw direction), additive (min feature size)?
Step 2: Choose Objective-Constraint Pair
| User Wants | Objective | Constraint |
|---|---|---|
| Lightest structure that's stiff enough | Minimize volume | Compliance ≤ limit |
| Stiffest structure at given weight | Minimize compliance | Volume ≤ 30% |
| Avoid resonance | Maximize frequency | Volume ≤ target |
| Reduce peak stress | Minimize max stress | Volume ≤ target |
Most common: Minimize compliance with volume ≤ 30%
Step 3: Define Design Responses
Design responses are the quantities optimization tracks:
| Response | When to Use |
|---|---|
VOLUME |
Almost always (for volume constraint) |
STRAIN_ENERGY |
Stiffness optimization |
EIGENFREQUENCY |
Vibration/resonance |
STRESS |
Stress-constrained design |
DISPLACEMENT |
Deflection limit |
Step 4: Set Objective Function
The objective is what gets optimized:
MINIMIZE_MAXIMUM- For compliance, stressMAXIMIZE_MINIMUM- For frequency
Step 5: Add Constraints
Constraints limit the design space:
RELATIVE_LESS_THAN_EQUAL- Percentage (volume ≤ 30%)ABSOLUTE_LESS_THAN_EQUAL- Fixed value (stress ≤ 200 MPa)
Step 6: Consider Manufacturing
| Constraint | Purpose |
|---|---|
| Min member size | Prevents thin, unmanufacturable features (3-5mm typical) |
| Symmetry | Mirrors design about plane |
| Draw direction | Enables mold/casting extraction |
| Overhang angle | For additive manufacturing |
Step 7: Freeze Critical Regions
Always freeze:
- BC application regions (mounting points)
- Load application regions
- Functional surfaces (mating interfaces)
Key Parameters
| Parameter | Recommended | Notes |
|---|---|---|
| SIMP penalty | 3.0 | Higher = sharper boundaries |
| Volume fraction | 0.3-0.4 | Start conservative |
| Min member size | 3× mesh size | Prevents checkerboard |
| Design cycles | 30-50 | More for complex geometry |
Validation Checklist
After setup, verify:
- Task created with correct region
- At least one design response defined
- Objective function set
- Volume or other constraint defined
- BC/load regions frozen
- Manufacturing constraint if needed
Troubleshooting
| Problem | Likely Cause | Solution |
|---|---|---|
| Checkerboard pattern | No min member size | Add GeometricRestriction |
| Disconnected result | Load path broken | Freeze more regions |
| Not converging | Constraint too tight | Relax volume fraction |
| "License error" | No Tosca module | Requires full Abaqus |
Code Patterns
For actual API syntax and code examples, see:
- API Quick Reference
- Common Patterns
- Troubleshooting Guide