Abaqus Shape Optimization Skill

Optimize surface geometry to reduce stress concentrations. Shape optimization moves existing surfaces without adding or removing material.

When to Use This Skill

Route here when user mentions:

"stress concentration", "reduce peak stress"
"fillet optimization", "optimize fillet radius"
"reshape surface", "smooth geometry"
"improve fatigue life", "notch optimization"

Route elsewhere:

Adding/removing material (holes, organic forms) → /abaqus-topology-optimization
Low-level optimization setup → /abaqus-optimization
Running the optimization job → /abaqus-job

Shape vs Topology Optimization

| Aspect | Shape Optimization | Topology Optimization | |--------|-------------------|----------------------| | What changes | Surface positions | Material presence | | Result | Smooth surfaces | Holes, organic forms | | Manufacturing | Traditional machining | Often needs AM/casting | | Design freedom | Limited | High | | Best for | Refine existing design | Conceptual design |

Rule of thumb: Use shape optimization when you have a good design with local stress issues. Use topology when starting fresh or need major redesign.

Prerequisites

Before shape optimization:

✅ Working static analysis that converges
✅ Identified high-stress surface region
✅ Full Abaqus license with Tosca (not Learning Edition)

Workflow: Shape Optimization

Step 1: Run Baseline Analysis

Run static analysis to identify stress concentrations. Note peak stress location and magnitude for comparison baseline.

Step 2: Identify Design Surfaces

Ask user if unclear: Which surfaces can be modified? Which must remain fixed?

Only select surfaces that can be modified in manufacturing, are not functional interfaces, and don't have attached features.

Step 3: Define Movement Limits

Get maximum growth/shrink (mm). Typical values: 3-10mm depending on part size.

Step 4: Choose Objective

| User Goal | Objective | Design Response | |-----------|-----------|-----------------| | Reduce stress concentration | MINIMIZE_MAXIMUM | STRESS (MISES) | | Uniform stress distribution | MINIMIZE_MAXIMUM | MAX_PRINCIPAL_STRESS | | Maximize stiffness | MINIMIZE_MAXIMUM | STRAIN_ENERGY |

Step 5: Add Constraints and Geometric Restrictions

Protect critical regions: BC surfaces, load surfaces, mating interfaces, precision features.

Common constraints: volume ≤ initial, maintain planar surfaces, mesh quality.

Step 6: Run Optimization

Set design cycles (20-30) and submit the optimization process.

Key Parameters

| Parameter | Recommended | Notes | |-----------|-------------|-------| | Max movement | 3-10mm | Based on part size | | Design cycles | 20-30 | More for complex shapes | | Mesh quality | MEDIUM | Balance speed/quality | | Smoothing | LAPLACIAN | Prevents mesh distortion |

What to Ask User

If not specified, clarify:

Which surface to reshape? - "The inner fillet at the L-bracket corner"
Maximum allowed movement? - "Up to 5mm growth, 3mm shrink"
Stress reduction target? - "Reduce from 450 MPa to under 300 MPa"
Volume constraint? - "Keep volume within 5% of original"

Validation Checklist

After optimization completes, verify:

[ ] Peak stress reduced at critical location
[ ] Volume constraint satisfied
[ ] Geometry still manufacturable
[ ] No mesh distortion warnings
[ ] Results converged (objective stable)

Post-Processing

Compare initial vs optimized stress contours
Export modified geometry if needed
Run final validation FEA on optimized shape
Check manufacturability with CAM or manufacturing engineer

Troubleshooting

| Problem | Likely Cause | Solution | |---------|--------------|----------| | Mesh distortion | Movement limits too large | Reduce max growth/shrink | | No improvement | Wrong design surfaces | Verify surface selection | | Convergence failure | Aggressive optimization | Add smoothing, smaller steps | | Volume increase | No volume constraint | Add volume ≤ initial constraint | | "License error" | No Tosca module | Requires full Abaqus |

Code Patterns

For actual API syntax and code examples, see:

Related Skills

/abaqus-optimization - Base optimization API and concepts
/abaqus-topology-optimization - For material removal optimization
/abaqus-static-analysis - Required baseline analysis