orcaflex-modal-analysis
Perform modal and frequency analysis on OrcaFlex models to extract natural frequencies, mode shapes, and identify dominant DOF responses. Use for VIV assessment, resonance identification, and structural dynamics characterization.
Best use case
orcaflex-modal-analysis is best used when you need a repeatable AI agent workflow instead of a one-off prompt.
Perform modal and frequency analysis on OrcaFlex models to extract natural frequencies, mode shapes, and identify dominant DOF responses. Use for VIV assessment, resonance identification, and structural dynamics characterization.
Teams using orcaflex-modal-analysis should expect a more consistent output, faster repeated execution, less prompt rewriting.
When to use this skill
- You want a reusable workflow that can be run more than once with consistent structure.
When not to use this skill
- You only need a quick one-off answer and do not need a reusable workflow.
- You cannot install or maintain the underlying files, dependencies, or repository context.
Installation
Claude Code / Cursor / Codex
Manual Installation
- Download SKILL.md from GitHub
- Place it in
.claude/skills/modal-analysis/SKILL.mdinside your project - Restart your AI agent — it will auto-discover the skill
How orcaflex-modal-analysis Compares
| Feature / Agent | orcaflex-modal-analysis | Standard Approach |
|---|---|---|
| Platform Support | Not specified | Limited / Varies |
| Context Awareness | High | Baseline |
| Installation Complexity | Unknown | N/A |
Frequently Asked Questions
What does this skill do?
Perform modal and frequency analysis on OrcaFlex models to extract natural frequencies, mode shapes, and identify dominant DOF responses. Use for VIV assessment, resonance identification, and structural dynamics characterization.
Where can I find the source code?
You can find the source code on GitHub using the link provided at the top of the page.
SKILL.md Source
# Orcaflex Modal Analysis
## When to Use
- Extract natural frequencies from OrcaFlex models
- Calculate mode shapes for risers, lines, and structures
- Identify dominant degrees of freedom in each mode
- Filter modes by specific DOF (heave, surge, pitch, etc.)
- VIV susceptibility screening (compare natural frequencies to shedding frequencies)
- Resonance identification for environmental loading
- Batch processing multiple water depths or configurations
## Prerequisites
- OrcaFlex license (for OrcFxAPI)
- Python environment with `digitalmodel` package installed
- Model files (.dat, .yml, or .sim)
## Python API
### Basic Modal Analysis
```python
from digitalmodel.orcaflex.orcaflex_modal_analysis import OrcModalAnalysis
# Initialize analyzer
modal = OrcModalAnalysis()
# Configure analysis
cfg = {
"default": {
"Analysis": {
*See sub-skills for full details.*
### Direct OrcFxAPI Usage
```python
import OrcFxAPI
# Load model and calculate statics
model = OrcFxAPI.Model()
model.LoadData("model.yml")
model.CalculateStatics()
# Configure modal analysis
spec = OrcFxAPI.ModalAnalysisSpecification(
*See sub-skills for full details.*
### Extract Dominant DOFs
```python
from digitalmodel.orcaflex.orcaflex_modal_analysis import OrcModalAnalysis
import pandas as pd
modal = OrcModalAnalysis()
# After running analysis, get summary
all_modes_summary_df = modal.all_file_summary["Case1"]
# Filter modes dominated by specific DOF
*See sub-skills for full details.*
## Related Skills
- [orcaflex-modeling](../orcaflex-modeling/SKILL.md) - Run OrcaFlex simulations
- [viv-analysis](../viv-analysis/SKILL.md) - VIV susceptibility assessment
- [orcaflex-static-debug](../orcaflex-static-debug/SKILL.md) - Static convergence troubleshooting
## References
- OrcFxAPI Modal Analysis: Orcina Documentation
- DNV-RP-C205: Environmental Conditions and Environmental Loads
- API RP 2RD: Design of Risers for Floating Production Systems
- Source: `src/digitalmodel/modules/orcaflex/orcaflex_modal_analysis.py`
- Config: `src/digitalmodel/base_configs/modules/orcaflex/orcaflex_modal_analysis.yml`
## Sub-Skills
- [Basic Modal Analysis (+1)](basic-modal-analysis/SKILL.md)
- [Model Preparation (+2)](model-preparation/SKILL.md)
## Sub-Skills
- [Version Metadata](version-metadata/SKILL.md)
- [[1.0.0] - 2026-01-17](100-2026-01-17/SKILL.md)
- [1. Static Equilibrium → Modal Analysis](1-static-equilibrium-modal-analysis/SKILL.md)
- [Mode Shapes CSV (+2)](mode-shapes-csv/SKILL.md)
- [DOF Percentage Calculation (+2)](dof-percentage-calculation/SKILL.md)
- [Common Errors and Fixes (+1)](common-errors-and-fixes/SKILL.md)
- [Expected Frequency Ranges (+1)](expected-frequency-ranges/SKILL.md)
- [With VIV Analysis (+1)](with-viv-analysis/SKILL.md)Related Skills
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