Abaqus Dynamic Analysis Skill
This skill handles explicit and implicit dynamics for impact, crash, drop test, and transient response analysis.
When to Use This Skill
Route here when user mentions:
- Impact, crash, collision, drop test
- Transient response, time-varying response
- Shock loading, blast loading, explosive loading
- High-speed events, wave propagation
- "What happens when it hits..."
Route elsewhere:
- Natural frequency extraction →
/abaqus-modal-analysis
- Static/constant loads →
/abaqus-static-analysis
- Harmonic/sinusoidal response → modal + steady-state dynamics
- Very long transients (minutes+) → consider implicit or quasi-static
Prerequisites
Before dynamic analysis:
- Geometry and mesh ready
- Material MUST have density defined (required for mass matrix)
- Understand event duration and loading type
Workflow: Setting Up Dynamic Analysis
Step 1: Gather Information from User
Ask if unclear:
- What's the event duration? Milliseconds, seconds, or longer?
- Initial velocity? For drop tests or impact
- Is contact involved? Parts colliding or touching
- What output needed? Stress, velocity, acceleration, energy?
Step 2: Choose Explicit vs Implicit
| Factor |
Explicit |
Implicit |
| Time scale |
Short (us to ms) |
Longer (ms to s) |
| Step size |
Automatic (very small) |
User-controlled |
| Nonlinearity |
Handles well |
May need iterations |
| Memory |
Lower |
Higher |
| Contact |
Natural handling |
Needs care |
| Best for |
Impact, crash |
Vibration, long transient |
Decision rule:
- Event < 10ms with impact/contact → Explicit
- Event > 100ms without severe nonlinearity → Implicit
- In between → Either can work, explicit often easier
Step 3: Set Time Period
| Event Type |
Typical Duration |
| High-speed impact |
0.1-10 ms |
| Drop test |
1-100 ms |
| Blast loading |
1-50 ms |
| Seismic/vibration |
1-100 s |
Step 4: Define Initial Conditions
For drop tests and impact:
- Set initial velocity on the impacting part/region
- Velocity is applied in the Initial step
Step 5: Configure Output
Field outputs: S (stress), U (displacement), V (velocity), A (acceleration), PEEQ (plastic strain)
History outputs for energy balance (explicit): ALLKE, ALLIE, ALLWK, ETOTAL
Step 6: Consider Mass Scaling (Explicit Only)
| Option |
Effect |
When |
| None |
True inertia |
Very short events, accuracy critical |
| At beginning |
Scale once |
Quasi-static explicit |
| Throughout |
Continuous scaling |
When inertia less important |
Warning: Mass scaling speeds up analysis but affects inertial response.
Step 7: Run and Validate
Use /abaqus-job to submit, then check:
- Energy balance (ETOTAL approximately constant)
- Stable time increment (explicit)
- Results physically reasonable
Key Parameters
| Parameter |
Explicit |
Implicit |
| Time period |
Event duration |
Event duration |
| Time increment |
Automatic |
Specify initial, min, max |
| Element library |
EXPLICIT |
STANDARD |
| Element type |
C3D8R recommended |
C3D8R or C3D8 |
| Hourglass control |
ENHANCED |
Default |
Validation Checklist
Troubleshooting
| Problem |
Likely Cause |
Solution |
| "Time increment too small" |
Small/distorted elements |
Use mass scaling or coarsen mesh |
| Energy balance error |
Hourglass or instability |
Check hourglass energy, add control |
| Analysis takes forever (explicit) |
Long time period |
Consider implicit instead |
| Convergence failure (implicit) |
Severe nonlinearity |
Use explicit or smaller increments |
Related Skills
/abaqus-material - Define density (required)/abaqus-amplitude - Time-varying loads/abaqus-field - Initial velocity and predefined fields/abaqus-interaction - Contact for impact problems/abaqus-odb - Results extraction
Code Patterns
For API syntax and code examples, see:
- API Quick Reference
- Common Patterns
- Troubleshooting Guide
1---2name: abaqus-dynamic-analysis3description: Complete workflow for dynamic analysis. Use when user mentions impact, crash, drop test, transient, or time-varying response. Handles explicit and implicit dynamics.4---56# Abaqus Dynamic Analysis Skill78This skill handles explicit and implicit dynamics for impact, crash, drop test, and transient response analysis.910## When to Use This Skill1112**Route here when user mentions:**13- Impact, crash, collision, drop test14- Transient response, time-varying response15- Shock loading, blast loading, explosive loading16- High-speed events, wave propagation17- "What happens when it hits..."1819**Route elsewhere:**20- Natural frequency extraction → `/abaqus-modal-analysis`21- Static/constant loads → `/abaqus-static-analysis`22- Harmonic/sinusoidal response → modal + steady-state dynamics23- Very long transients (minutes+) → consider implicit or quasi-static2425## Prerequisites2627Before dynamic analysis:281. Geometry and mesh ready292. **Material MUST have density defined** (required for mass matrix)303. Understand event duration and loading type3132## Workflow: Setting Up Dynamic Analysis3334### Step 1: Gather Information from User3536Ask if unclear:37- **What's the event duration?** Milliseconds, seconds, or longer?38- **Initial velocity?** For drop tests or impact39- **Is contact involved?** Parts colliding or touching40- **What output needed?** Stress, velocity, acceleration, energy?4142### Step 2: Choose Explicit vs Implicit4344| Factor | Explicit | Implicit |45|--------|----------|----------|46| Time scale | Short (us to ms) | Longer (ms to s) |47| Step size | Automatic (very small) | User-controlled |48| Nonlinearity | Handles well | May need iterations |49| Memory | Lower | Higher |50| Contact | Natural handling | Needs care |51| Best for | Impact, crash | Vibration, long transient |5253**Decision rule:**54- Event < 10ms with impact/contact → **Explicit**55- Event > 100ms without severe nonlinearity → **Implicit**56- In between → Either can work, explicit often easier5758### Step 3: Set Time Period5960| Event Type | Typical Duration |61|------------|------------------|62| High-speed impact | 0.1-10 ms |63| Drop test | 1-100 ms |64| Blast loading | 1-50 ms |65| Seismic/vibration | 1-100 s |6667### Step 4: Define Initial Conditions6869For drop tests and impact:70- Set initial velocity on the impacting part/region71- Velocity is applied in the Initial step7273### Step 5: Configure Output7475Field outputs: `S` (stress), `U` (displacement), `V` (velocity), `A` (acceleration), `PEEQ` (plastic strain)7677History outputs for energy balance (explicit): `ALLKE`, `ALLIE`, `ALLWK`, `ETOTAL`7879### Step 6: Consider Mass Scaling (Explicit Only)8081| Option | Effect | When |82|--------|--------|------|83| None | True inertia | Very short events, accuracy critical |84| At beginning | Scale once | Quasi-static explicit |85| Throughout | Continuous scaling | When inertia less important |8687**Warning:** Mass scaling speeds up analysis but affects inertial response.8889### Step 7: Run and Validate9091Use `/abaqus-job` to submit, then check:92- Energy balance (ETOTAL approximately constant)93- Stable time increment (explicit)94- Results physically reasonable9596## Key Parameters9798| Parameter | Explicit | Implicit |99|-----------|----------|----------|100| Time period | Event duration | Event duration |101| Time increment | Automatic | Specify initial, min, max |102| Element library | EXPLICIT | STANDARD |103| Element type | C3D8R recommended | C3D8R or C3D8 |104| Hourglass control | ENHANCED | Default |105106## Validation Checklist107108- [ ] Density defined in material109- [ ] Time period appropriate for event110- [ ] Initial conditions applied (velocity, position)111- [ ] Output frequency captures behavior (100+ frames typical)112- [ ] Energy balance acceptable (ETOTAL constant for explicit)113- [ ] Results physically reasonable114115## Troubleshooting116117| Problem | Likely Cause | Solution |118|---------|--------------|----------|119| "Time increment too small" | Small/distorted elements | Use mass scaling or coarsen mesh |120| Energy balance error | Hourglass or instability | Check hourglass energy, add control |121| Analysis takes forever (explicit) | Long time period | Consider implicit instead |122| Convergence failure (implicit) | Severe nonlinearity | Use explicit or smaller increments |123124## Related Skills125126- `/abaqus-material` - Define density (required)127- `/abaqus-amplitude` - Time-varying loads128- `/abaqus-field` - Initial velocity and predefined fields129- `/abaqus-interaction` - Contact for impact problems130- `/abaqus-odb` - Results extraction131132## Code Patterns133134For API syntax and code examples, see:135- [API Quick Reference](references/api-quick-ref.md)136- [Common Patterns](references/common-patterns.md)137- [Troubleshooting Guide](references/troubleshooting.md)
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