How to obtain the ZERO POSITIVE CROSSING to perform a FATIGUE Analysis

Luca_97

Hi,

I need to obtain the Zero Positive Crossing to perform a fatigue Analysis. I find something online but it isn't clear.

https://2021.help.altair.com/2021/hwsolvers/os/topics/solvers/os/analysis_random_response_r.htm

In particular, I didn't understand in which element I need to see these value.

Thank you

solon

If you run a Random Response analysis using Optistruct, there are two ways of getting the number of Zero positive crossing:

1. Using XYPEAK output, you will get a punch file (*.pch) including the number of zero positive crossing. https://help.altair.com/hwsolvers/os/topics/solvers/os/xypeak_xyplot_xypunch_io_r.htm?zoom_highlight=xypeak

2. Using the stress output request with the option PSDM: You can request STRESS(PSDM)=ALL to have the number of zero crossings in your results.

For Random Fatigue analysis these calculations will be performed internally by the solver, so there is no need to request the zero crossing output: https://help.altair.com/hwsolvers/os/topics/solvers/os/analysis_random_response_fatigue_c.htm?zoom_highlight=random+fatigue

https://community.altair.com/discussion/40952/random-fatigue-and-cycle-counting