Abaqus Contact Analysis Workflow

This skill guides multi-body contact analysis setup. It's a workflow skill - use it when analyzing assemblies where surfaces touch, slide, or separate.

When to Use This Skill

Route here when user mentions:

•"Parts touching each other"
•"Contact between surfaces"
•"Friction between parts"
•"Bolt and plate contact"
•"Press fit / interference fit"
•"Multi-body assembly"
•"Parts sliding on each other"
•"Impact analysis"
•"Bearing contact"

Route elsewhere:

•Single-body analysis → /abaqus-static-analysis
•Just defining contact properties → /abaqus-interaction
•Only boundary conditions → /abaqus-bc

Prerequisites

Before contact analysis setup:

•Separate parts exist (at least two bodies)
•Parts are positioned in assembly with appropriate gap/interference
•Material properties defined for all parts
•Basic understanding of which surfaces will touch

Workflow Steps

Step 1: Identify Contact Pairs

Ask the user:

•Which surfaces will touch?
•Is there an initial gap or interference?
•Will surfaces slide or remain bonded?

Step 2: Determine Master vs Slave

Role	Should Be
Master	Stiffer material, coarser mesh
Slave	Softer material, finer mesh

Rule: Slave surface nodes cannot penetrate master surface.

Step 3: Choose Contact Type

Scenario	Approach
Permanently bonded surfaces	Tie constraint (no slip/separation)
Sliding with friction	Surface-to-surface contact
Frictionless contact	Surface-to-surface, no tangential
Many bodies touching	General contact (auto detection)
Surface folding on itself	Self-contact

Step 4: Define Contact Property

Configure normal behavior:

•Hard contact - Most cases, no penetration allowed
•Soft contact - For rubber, foam, or gradual engagement

Configure tangential behavior (if not tied):

•Frictionless - Lubricated surfaces
•Friction (Coulomb) - Specify coefficient

Step 5: Set Friction Coefficient

Interface	Typical Value
Frictionless	0.0
Lubricated steel	0.1-0.2
Dry steel-on-steel	0.3-0.5
Rubber on metal	0.5-0.8

Ask user if unsure about their specific interface.

Step 6: Create Analysis Step

Contact analysis typically requires:

•Nonlinear geometry (nlgeom=ON)
•Smaller initial increment (0.1)
•More increments allowed (100+)
•Minimum increment for convergence (1e-8)

Step 7: Request Contact Outputs

Essential output variables:

•CSTRESS - Contact pressure and shear
•CDISP - Contact displacement
•COPEN - Gap opening distance
•CSLIP - Accumulated slip

Key Decisions

User Need	Configuration
Bonded joint (welded, glued)	Tie constraint
Bolted connection	Friction contact + preload
Press fit	Interference + friction
Bearing load	Frictionless or low friction
Impact/crash	Explicit dynamics + general contact

What to Ask User

•Surfaces: Which surfaces will touch?
•Motion: Will parts slide, separate, or stay bonded?
•Friction: Dry contact, lubricated, or frictionless?
•Gap/interference: Initial configuration?
•Loading: What pushes the parts together?

Validation Checklist

After setup, verify:

• Master/slave assigned correctly (stiffer = master)
• Contact property has normal behavior defined
• Tangential behavior set (friction or frictionless)
• nlgeom=ON in analysis step
• Contact outputs requested (CSTRESS, CDISP)
• Boundary conditions don't overconstrain

Troubleshooting

Problem	Likely Cause	Solution
"Severe discontinuity"	Contact chattering	Add stabilization, smaller increments
"Too much penetration"	Wrong master/slave	Swap roles, refine slave mesh
"Contact not detected"	Surfaces too far apart	Use adjust=ON or reduce gap
"Convergence failure"	Difficult nonlinearity	Smaller increments, check friction

Code Patterns

For API syntax and code examples, see:

Related Skills

•/abaqus-interaction - Contact property details
•/abaqus-bc - Boundary conditions
•/abaqus-step - Nonlinear step settings
•/abaqus-dynamic-analysis - For impact problems