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, stress
MAXIMIZE_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: