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It could be related to your data or to your software revision. What type of cursor is not showing the processing option (order, frequency, or Z)? What revision of Testlab software (2019 or higher)? Is the data plotted against rpm if trying to use the order cursor?

@@SimcenterTesting The version I am using is Testlab Build: 210120 Neo. I can't find any processing cursors, whether it's X, order, frequency, or Z. In the data I’m using, the X-axis quantity is HZ Frequency and the Y-axis quantity is rpm RotationalSpeed. I'm new to Neo, but I am quite familiar with the Standard version of Testlab. In that version, I can add processing cursors (X, Z, frequency, order, cross) in any display. Why can't I do this in the Neo version?

@@SimcenterTesting It seems like I've found the reason. It’s probably because I was using the 2021.1 version and had installed the Standard version instead of the Advanced version. After reinstalling the Advanced version, my dear processing cursor appeared.

A third reason - thanks for letting us know for posterity!

See section 7 of this article: community.sw.siemens.com/s/article/Calculating-and-Comparing-Orders-and-Overall-Levels-in-Simcenter-Testlab-Neo

That is not always true. If trying to correlate to a free-free simulation model of the test object then hanging from a soft suspension can approximate the same conditions as the free-free simulation model. If the modes of the test object as installed are of interest, then it would be mounted as it is used in a real life application. The simulation model can also reflect real life boundary conditions as well. Further discussion in the boundary conditions section of this article: community.sw.siemens.com/s/article/Modal-Testing-A-Guide

@@SimcenterTesting thanks for your response😊

If understanding your question correctly, the FFT of an acceleration (g) curve versus time is a frequency spectrum of acceleration (g) versus frequency. There are some additional considerations: community.sw.siemens.com/s/article/the-autopower-function-demystified

The half-power method is defined based on the FRF, so to use the half-power method you would need to measure the input to the spring. Alternatively, you could use the logarithmic decrement method. This does not require you to measure the force and does not require an FFT.

@@Will_Rog42 DO you think we can measure damping ratio using Log decriment without FFT and input force?

You have to contact your local Siemens office: plm.sw.siemens.com/en-US/contact-plm/. The official website about the product the contact link is here: plm.sw.siemens.com/en-US/simcenter/simulation-test/acoustic-testing/active-sound-design/

The hysteresis filter is used to remove small cycles. We do it always with at least the size of 1 bin width. So, all cycles that are smaller than 1 bin width are ignored. The peak valley filtering mentioned in the video will remove monotonic parts between turning points. Without the hysteresis filter there would be much more turning points and you would end up with cycles on the main diagonal. These would be cycles with a reference amplitude of zero (after the binning). So, it does not make much sense in keeping them with respect to damage. Other filters can be applied in time domain before doing the Rainflow counting, but they are not embedded in the Rainflow counting algorithm as we have implemented it. But be careful with applying filters that modify the amplitude: this will modify the damage!

Cyclic fatigue is independent of time. Any stress cycle could be applied slowly or quickly. In the end, the number of complete cycles applied is what matters. If cycles in real life usage are applied quickly, the part will fail faster than if they are applied slowly over time.

@@SimcenterTesting so is it means, I need to know the value of time during the stress cycle? If I want to convert the cycles to time?

Neo has an updated user interface compared to Testlab ""Classic" which is faster to use for many tasks. There is a lot of overlap in functionality between Neo and Testlab, and some newer features in Neo. Here is some more information on Simcenter Testlab Neo: community.sw.siemens.com/s/article/Simcenter-Testlab-Neo-Introduction

For Tonality - Classic tonality which has a range of 0 (no tones) to 1 (very tonal) is in Testlab. Tonality HMS which goes from 0 to beyond 1 also by considering the loudness level is available in Simcenter Testlab Neo: community.sw.siemens.com/s/article/Tonality

28:37 - it is actually a single slope linear approximation of the Whoeler curve (Basquin law N σ^b=A^b). The natural frequencies are defined by the “frequency axis parameters”. For this analysis and for SRS calculations, there is a subtle but important difference between the two, as pointed out in the articles community.sw.siemens.com/s/article/Fatigue-Damage-Spectrum and community.sw.siemens.com/s/article/shock-response-spectrum-srs

Do not confuse the SDOF systems with the natural frequencies of the test object. Mission Synthesis goal is to derive the input to a test article whose resonant frequencies are unknown. FDS uses for this scope a generalized resonance model under the assumption that (unknown) resonances ultimately lead to fatigue failure. Frequency spacing limits are often suggested by standards (e.g min xx points per octave), but I find a good practice for defining the frequency spacing to quickly analyze the frequency content of the input events upfront to make sure I am not cutting out input energy. For example, if the input signals show a clear sharp peak at around 4 Hz, a 2 Hz resolution starting at 1 Hz will lead to [1,3,5, …] Hz frequency axis which will result in an interpolated value at the critical 4 Hz frequency. It would be better to start at 1 Hz and define a 1 Hz resolution (or at 2 Hz with a 2 Hz resolution, for the sake of this example).

Suggest reading section 4.5 of this article: community.sw.siemens.com/s/article/shock-response-spectrum-srs

The software can read wave files and numpy files?

In our software, the minimum gate is 1 bin width. This will avoid cycles on the main diagonal which would have a reference physical range of 0. This would not add to the damage anyway. You can use larger gates, then this value should relate to the endurance limit of the material you are measuring/testing. So, the gate should only exclude cycles where you are super sure that they will not add to your damage.

In a dynamic mode of a structure, modes that occur at different frequencies can be local to smaller components of the structure. These components can be made of different materials, have different boundary conditions, or the material is not uniform throughout the structure.

File -> Printing Options -> Default Microsoft Application set to Microsoft Word.

Only the inner points build a closed hysteresis loop in the stress/strain path. To close the cycle built by the inner points, you need the outer points. Later, the outer points might become inner points of some larger points. Then they are counted as well.

An autopower is based on the fourier transform, but it is squared to remove phase: community.sw.siemens.com/s/article/the-autopower-function-demystified. Both a Fourier Transform and a Autopower are typically calculated based on a single signal. A cross power is frequency function calculated between two separate signals.