rfcnt 0.5.2.post2

Python interface for rainflow counting

Rainflow Python Package (rfcnt)

Summary

The rfcnt package provides a high-performance, standards-compliant implementation of the rainflow counting algorithm for fatigue analysis, with bindings for Python, C/C++, and MATLAB. It supports the 4-point method (DIN 45667), the ASTM E 1049 3-point method, HCM (Clormann/Seeger), and advanced residue handling. This README summarizes the package for users and developers. For full documentation, see the /docs folder.

Features

• Fast C core with Python and MATLAB wrappers
• 4-point, HCM, and ASTM counting methods
• Flexible residue processing (DIN, ASTM, repeated, ignore, HCM)
• Streaming and batch processing
• Dynamic class management (auto-resize, offset)
• Compile-time feature selection (minimal, delegates, damage history, etc.)
• Unit tests and real-world examples

Algorithm Overview

Rainflow counting extracts closed cycles from load histories in four main steps:

1. Hysteresis Filtering: Removes small oscillations below a threshold
2. Peak-Valley Filtering: Identifies turning points
3. Discretization: Maps values to classes (bins)
4. 4-Point Counting: Detects closed cycles using the 4-point pattern

A cycle B-C is closed if:

min(B, C) >= min(A, D) and max(B, C) <= max(A, D)

Closed cycles are counted and removed; residue is handled per user choice.

Installation

Prerequisites:

• Python 3.6+
• NumPy (>=2.0)
• CMake 3.16+
• C/C++ compiler (GCC, Clang, MSVC)

Build and Install:

cmake -S. -Bbuild -DRFC_EXPORT_PY=1
cmake --build build --target build_wheel_isolated --config Release
pip install dist/rfcnt-*.whl

Or install from source:

pip install . --no-build-isolation --no-deps

MATLAB: See docs/installation.rst for MATLAB integration.

Quick Start

import numpy as np
import rfcnt

data = np.array([0.0, 1.0, 0.0, 2.0, 0.0, 3.0, 0.0])
result = rfcnt.rfc(data, class_width=0.5, class_count=10)
print("Total damage:", result['damage'])
print("Range pairs:\n", result['rp'])

Advanced Usage

• Use Wöhler curve parameters for fatigue life prediction
• Select counting method: use_HCM, use_ASTM
• Control residue handling: residual_method
• Enable damage history: spread_damage
• Integrate with real-time or embedded systems (RFC_MINIMAL)

Example:

result = rfcnt.rfc(
    data,
    class_width=5.0,
    use_HCM=True,
    spread_damage=rfcnt.SDMethod.TRANSIENT_23c,
    hysteresis=2.5
)

Documentation

• Algorithm details: docs/algorithm.rst
• Features: docs/features.rst
• Examples: docs/examples.rst
• Installation: docs/installation.rst
• References: docs/references.rst

References

[1] ASTM E 1049, "Standard Practices for Cycle Counting in Fatigue Analysis", ASTM International, 2011.

[2] U.H. Clormann, T. Seeger, "Rainflow - HCM / Ein Hysteresisschleifen-Zaehlalgorithmus...", TU Darmstadt, 1985.

[3] FVA-Richtlinie, 2010. https://fva-net.de/fileadmin/content/Richtlinien/FVA-Richtlinie_Zaehlverfahren_2010.pdf

[4] Siemens PLM, "Rainflow Counting", 2018. https://community.plm.automation.siemens.com/t5/Testing-Knowledge-Base/Rainflow-Counting/ta-p/383093

For a full bibliography, see docs/references.rst.

License

See LICENSE file.

Contact

For questions, bug reports, or contributions, see the project repository or contact the maintainer.