Simcenter Testing Solutions Difference between "Range-Mean" and "From-To" cycle counting
Summary
Details
The unsymmetrical From-To cycle counting keeps more information about the loading cycles than Range-Mean counting does, because it also stores the "orientation" of each load cycle. This is important information if you want to reconstruct a time history from a Rainflow matrix.
The Rainflow counting of Simcenter Tecware (formerly called LMS Tecware) is a From-To cycle counting, and thus the default representation of the Rainflow matrices are also in From-To form.
However, Tecware also allows changing the representation to Range-Mean matrices. In fact, a Range-Mean histogram can always be derived from a From-To histogram, but not vice versa. This is because the From-To representation includes additional information (as mentioned above).
Example:
Look at the two load histories below:
They both have the same mean level and the same number of cycles, and the cycles' amplitudes are identical. The only distinctive property is the opposite polarity.
Looking at the Rainflow matrices of the two load histories, we get in the From-To representation:
The Rainflow matrix of "Load_up" shows hanging cycles, whereas the corresponding Rainflow matrix of "Load_down" shows standing cycles.
The denotation hanging and standing is motivated from the stress-strain-path. There, a hanging event is connected to the superior hysteresis branch at its upper reversal point, but a standing event is connected at its lower reversal point.
When a load cycle is just represented by its range and mean, the distinction between hanging and standing is not possible. Thus, the Range-Mean representation for both of the signals looks like this:
Remarks:
The desired representation of a Rainflow matrix can be set in the "RainView layout" window, which is available via the menu Options -> Layout within the Rainflow matrix display.
Rainflow matrices can only be edited in the From-To representation.
Questions? Contact Siemens Support Center or post a reply.
More Fatigue and Durability links:
- Index of Testing Knowledge Articles
- Free On-Demand Webinar: Fundamentals of Fatigue
- History of Fatigue
- Stress and Strain
- Calculating Damage with Miner's Rule
- What is a SN-Curve?
- Goodman-Haigh Diagram for Infinite Life
- Rainflow Counting
- Power Spectral Density
- Shock Response Spectrum (SRS)
- How to Calculate a Shock Response Spectrum with Testlab?
- Some Thoughts on Accelerated Durability Testing
- Measuring strain gauges in Simcenter Testlab
- Rosette Strain Gauges
- Calculating Damage in Simcenter Tecware Process Builder
- Strain Gauges: Selecting an Excitation Voltage
- Simcenter Testlab SCADAS and Long Strain Cables
Simcenter Tecware links:
- Running Simcenter Tecware with Simcenter Testlab tokens
- Simcenter Tecware: Open Time Files fast!
- Simcenter Tecware: Overlay multiple signals in X and Y display
- Simcenter Tecware: Access to different file formats
- Simcenter Tecware: Spike Filter
- Simcenter Tecware: Removing Multiple Segments
- Simcenter Tecware: Calculate Infinite Life with the Goodman Diagram
- Calculating damage with Simcenter Tecware Processbuilder
- Using Simcenter Tecware processes in Simcenter Testlab Neo
- Butterworth filter "regular" and "zero phase"