| name | abaqus-interaction |
| description | Define contact and interactions - contact pairs, tie constraints, connectors. Use when user mentions contact, friction, tie, parts touching, or bonded surfaces. |
| allowed-tools | ["Read","Write","Edit","Glob","Grep","Bash(abaqus:*)"] |
Abaqus Interaction Skill
Define contact pairs, tie constraints, coupling, and connectors between parts in an assembly.
When to Use This Skill
Route here when user mentions:
- "Contact between surfaces"
- "Friction", "sliding contact", "frictionless"
- "Tie constraint", "bonded surfaces", "welded"
- "Parts touching", "parts can separate"
- "Coupling", "connector", "spring element"
- "Join different meshes"
Route elsewhere:
- Complete contact analysis workflow →
/abaqus-contact-analysis
- Fixed supports or displacements →
/abaqus-bc
- Applied forces or pressures →
/abaqus-load
Key Decisions
1. What Type of Connection?
| User Describes | Interaction Type | Key Feature |
|---|
| Welded, glued, bonded | Tie constraint | Permanent, no relative motion |
| Parts can slide and separate | Surface-to-surface contact | Friction, gap allowed |
| Load from point to surface | Coupling | Reference point control |
| Spring, damper, hinge | Connector | Stiffness/damping behavior |
| Adhesive, delamination | Cohesive | Damage initiation criteria |
2. Contact Formulation
| Formulation | When to Use |
|---|
| Surface-to-surface | General contact (recommended default) |
| Node-to-surface | Legacy compatibility, special cases |
| General contact | Automatic detection (explicit dynamics) |
| Self-contact | Folding, buckling, large deformation |
3. Typical Friction Coefficients
| Surface Pair | Friction Coefficient |
|---|
| Frictionless | 0.0 |
| Lubricated metal | 0.1 - 0.3 |
| Dry metal-to-metal | 0.3 - 0.5 |
| Rubber on surface | 0.5 - 0.8 |
| No slip (rough) | Use ROUGH formulation |
What to Ask User
If unclear, ask:
-
Bonded or sliding?
- Bonded (no relative motion) → Tie constraint
- Sliding allowed → Contact with friction
-
Friction coefficient?
- If not specified, suggest typical value for material pair
- Frictionless is valid for lubricated or normal-dominant cases
-
Which surface is master/slave?
- User may not know - guide them (see below)
-
Can surfaces separate?
- Yes →
allowSeparation=ON
- No (always in contact) →
allowSeparation=OFF
Master/Slave Selection Guidelines
| Criterion | Master Surface | Slave Surface |
|---|
| Stiffness | Stiffer body | Softer body |
| Mesh density | Coarser mesh | Finer mesh |
| Size | Larger surface | Smaller surface |
| Geometry | Flat/convex | Curved/concave |
When in doubt: The coarser mesh should be master.
Workflow: Setting Up Interactions
Step 1: Identify Contact Pairs
List all surfaces that interact. For each pair determine:
- Type (contact vs tie)
- Master and slave assignment
- Friction requirements
Step 2: Create Surfaces
Surfaces must be defined on assembly instances before creating interactions.
Step 3: Define Contact Properties
For contact interactions, define:
- Normal behavior: Hard contact, allow separation
- Tangential behavior: Friction formulation and coefficient
Step 4: Create Interaction
Assign contact property to surface pair in appropriate step.
Step 5: Verify Setup
Check for:
- Correct master/slave assignment
- Appropriate initial gap/overclosure
- Contact pair is active in correct step
Common Gotchas
| Symptom | Likely Cause | Solution |
|---|
| Contact not detected | Surfaces too far apart | Use adjust=ON or reduce initial gap |
| Severe discontinuity warnings | Contact chattering | Add stabilization, use smaller increments |
| Negative eigenvalue | Wrong master/slave | Swap master and slave surfaces |
| Overclosure too large | Initial interference | Use shrink fit option or adjust geometry |
| Tie not working | Surfaces not close enough | Increase position tolerance |
Validation Checklist
Before running analysis:
Code Patterns
For API syntax and code examples, see:
