Repository files navigation

1. Hysteresis Filtering

2. Peak-Valley Filtering

3. Discretization

4. Four Point Counting Method:

               * D           / \       Closed, if min(B,C) >= min(A,D) && max(B,C) <= max(A,D)    B *<--/          Slope B-C is counted and removed from residue     / \ /    /   * C \ /  * A

These steps are fully documented in standards such asASTM E 1049 "Standard Practices for Cycle Counting in Fatigue Analysis" [1]This implementation uses the 4-point algorithm mentioned in [3,4] and the 3-point HCM method proposed in [2] as well as the ASTM E 1049 (2011) standard in [1].To take the residue into account, you may implement a custom method or use somepredefined functions.

1. Modular architecture in two layers:
   • Modulerainflow.c (withrainflow.h) holds all necessary functions for rainflow counting and histogram extraction. You may select multiple optional features at compile time:
     RFC_MINIMAL: To use core functions for rainflow counting only (for porting to µControllers for example).
     RFC_TP_SUPPORT: Turning point storage.
     RFC_HCM_SUPPORT: HCM algorithm (Clormann/Seeger).
     RFC_ASTM_SUPPORT: ASTM E 1049 (2011) algorithm.
     RFC_AT_SUPPORT: User defined amplitude transformation (Haigh diagram).
     RFC_DH_SUPPORT: Damage history storage.
     RFC_USE_DELEGATES: Delegates for various core functions to implement user defined behavior.
     RFC_GLOBAL_EXTREMA: Store global data extrema.
     RFC_DAMAGE_FAST: Using lookup tables for damage and amplitude transformation.
     RFC_EXPORT_MEX: Export a mexFunction() to use the rainflow counting in MATLAB (R).
     RFC_EXPORT_PY: Export a Python extension to use the rainflow counting in Python.
     RFC_UNIT_TEST: Build an executable for unit testing.
     UsingCOAN [[http://coan2.sourceforge.net/]] for example, you can tidy up the code from unwanted features.
     (The minimal version of this package is created usingCOAN with optionRFC_MINMALset.)
   • C++ wrapperrainflow.hpp encapsulates functions from rainflow.h in a namespace and offers a template classRainflow for object oriented access and inheritance.
     This class also offers container class based turning point storage.
2. Streamable: You're able to count your data at once, as data packages or sample-wise.
3. Class width fit to your needs. Dynamically increase class width, when needed. (Needs turning point storage.)
4. Four point counting method, optionally HCM counting method (Clormann/Seeger).
5. Woehler curve with up to two slopes, fatigue limit and omission.
6. Miners rule for damage accumulation (elementary, original, modified and consequent).
7. In-time damage indicator (Miners' consequent rule).
8. In-time histograms: rainflow matrix, level crossing and range pair counting.
9. Turning points with hysteresis filtering. Turning points involved in a closed hysteresis are marked as pairs, with its partial assigned damage. (Compact history)
10. Look-up tables for damage calculation and amplitude transformation.
11. Amplitude transformation (Haigh diagram) according to FKM (symmetrical, non-symmetrical or user defined).
12. Damage history (uncompressed)
13. Various methods on residual data:
    • According to DIN 45667
    • ASTM method (halfcycle, fullcycle)
    • Second run
    • HCM
14. Various function pointers to implement user defined behavior.
15. Conversions supporting RFM->LC, RFM->RP, RFM->Damage and RP->Damage (original, elementar, modifiziert, konsequent).

Building makefiles from sources root folder in a shell:

cmake -S. -Bbuild -G "Visual Studio 16 2019"cmake --build build --config Release

If you intend to use a special MATLAB(R) installation to build the projectjust set an environment variableMatlab_ROOT_DIR such as

export Matlab_ROOT_DIR=/usr/local/MATLAB/R2019b

or use the option to configure the build tree:

cmake -S. -Bbuild -DMatlab_ROOT_DIR=/usr/local/MATLAB/R2017b -G "Visual Studio 16 2019"cmake --build build --config Release

cmake -S. -Bbuild -DRFC_EXPORT_PY=0 -DRFC_UNIT_TEST=0 -G "Visual Studio 16 2019"cmake --build build --target rfc_mex --config Release

cmake -S. -Bbuild -DRFC_EXPORT_MEX=0 -DRFC_UNIT_TEST=0 -G "Visual Studio 16 2019"cmake --build build --target rfcnt --config Release

To build a Python package (wheel) you don't need cmake. Use packagessetuptools,wheel andbuild instead:

cd src/pythonpip install setuptools build wheel oldest-supported-numpypython -mbuild -nw

python -m rfcnt.run_examples

Using rfcnt in Google Colaboratoryhttps://colab.research.google.com

!pip install --no-build-isolation --no-deps https://github.com/a-ma72/rainflow/releases/download/rfcnt-0.4.7rc0/rfcnt-0.4.7rc0.tar.gzimport rfcntrfcnt.tests.examples.example_1()

Currently, two options are offered to perform a unit test:

1. Buildrfc_test and execute in a shell:

    cmake -S. -Bbuild -DRFC_EXPORT_PY=0 -DRFC_EXPORT_MEX=0 -G "Visual Studio 16 2019" cmake --build build --target rfc_test --config Release

   Then invoke the unit test:

    build/test/Release/rfc_test      # Linux build\test\Release\rfc_test.exe  # Windows

   or

    ctest -C Release

2. Run Python code (shell):

   python -m rfcnt.run_tests

[1] "Standard Practices for Cycle Counting in Fatigue Analysis."
ASTM Standard E 1049, 1985 (2011).
West Conshohocken, PA: ASTM International, 2011.
[2] "Rainflow - HCM / Ein Hysteresisschleifen-Zaehlalgorithmus auf werkstoffmechanischer Grundlage"
U.H. Clormann, T. Seeger
1985 TU Darmstadt, Fachgebiet Werkstoffmechanik
[3] "Zaehlverfahren zur Bildung von Kollektiven und Matrizen aus Zeitfunktionen"
FVA-Richtlinie, 2010.
[https://fva-net.de/fileadmin/content/Richtlinien/FVA-Richtlinie_Zaehlverfahren_2010.pdf]
[4] Siemens Product Lifecycle Management Software Inc., 2018.
[https://community.plm.automation.siemens.com/t5/Testing-Knowledge-Base/Rainflow-Counting/ta-p/383093]
[5] "Review and application of Rainflow residue processing techniques for accurate fatigue damage estimation"
G.Marsh;
International Journal of Fatigue 82 (2016) 757-765,
[https://doi.org/10.1016/j.ijfatigue.2015.10.007]
[6] "Betriebsfestigkeit - Verfahren und Daten zur Bauteilberechnung"
Haibach, Erwin; Springer Verlag
[] "Schaedigungsbasierte Hysteresefilter"; Hack, M, D386 (Diss Univ. Kaiserslautern), Shaker Verlag Aachen, 1998, ISBN 3-8265-3936-2
[] "Hysteresis and Phase Transition"
Brokate, M.; Sprekels, J.; Applied Mathematical Sciences 121; Springer, New York, 1996
[] "Rainflow counting and energy dissipation in elastoplasticity"; Eur. J. Mech. A/Solids 15, pp. 705-737, 1996
Brokate, M.; Dressler, K.; Krejci, P.
[] "Multivariate Density Estimation: Theory, Practice and Visualization". New York, Chichester, Wiley & Sons, 1992
Scott, D.
[] "Werkstoffmechanik - Bauteile sicher beurteilen undWerkstoffe richtig einsetzen";
Ralf Buergel, Hans Albert Richard, Andre Riemer; Springer FachmedienWiesbaden 2005, 2014
[] "Zaehlverfahren und Lastannahme in der Betriebsfestigkeit";
Michael Koehler, Sven Jenne / Kurt Poetter, Harald Zenner; Springer-Verlag Berlin Heidelberg 2012