Abaqus Step

Abaqus Step Skill

This skill defines analysis steps and procedures in Abaqus. Steps control what physics are solved and how the solution proceeds.

When to Use This Skill

Route here when user mentions:

• "static analysis", "dynamic step", "frequency analysis"
• "heat transfer step", "thermal step", "transient analysis"
• "analysis type", "time increments", "nlgeom"
• "convergence issues", "increment size", "time step"
• "multi-step analysis", "sequential loading"
• "buckling analysis", "modal analysis"
• "impact simulation", "crash analysis"

Route elsewhere:

• Applying boundary conditions → /abaqus-bc
• Applying loads → /abaqus-load
• Setting up optimization → /abaqus-optimization
• Configuring output requests → /abaqus-output

Workflow: Creating Analysis Steps

Step 1: Understand User's Physics

Ask if unclear:

• What physics? Stress, vibration, heat transfer, coupled?
• Static or dynamic? Constant load vs time-varying?
• Linear or nonlinear? Small or large deformations?

Step 2: Choose Step Type

Most common: StaticStep with nlgeom=OFF for linear stress analysis.

Step 3: Determine Linearity

Step 4: Configure Increment Control

Step 5: Chain Multiple Steps (if needed)

For sequential loading:

1. First step uses previous='Initial'
2. Subsequent steps chain from previous step name
3. Each step can have different physics or settings

Key Parameters

Special Considerations

Frequency/Modal Analysis

• Always from Initial step (no preload needed for basic modal)
• Use LANCZOS eigensolver for large models
• Extract 10-20 modes typically

Buckling Analysis

• Usually follows a load step (to apply reference load)
• Eigenvalues are load multipliers
• First positive eigenvalue is critical

Explicit Dynamics

• Time period should be very short (milliseconds)
• Increment size determined automatically
• Mass scaling may be needed for quasi-static problems

Heat Transfer

• STEADY_STATE for equilibrium temperature
• TRANSIENT for time-varying temperature
• deltmx controls accuracy vs speed

Troubleshooting

Validation Checklist

After step creation, verify:

• Step type matches analysis physics
• nlgeom setting appropriate for deformation level
• Increment control parameters reasonable
• Step chains correctly from previous
• Time period appropriate for transient analysis

Code Patterns

For actual API syntax and code examples, see:

• API Quick Reference
• Common Patterns
• Troubleshooting Guide