Calculating Grms from random vibration profile

[FakeCaptainGabriel]

Hello there, I'd like to find out if inventor nastran is able to ouput grms after running the random response?

If not, how do i calculate grms for a random profile? Please advise. I am new

Thank you

Gabriel

[John_Holtz]

I think the steps would be to set the output of the acceleration results ("Analysis > Edit > Output Controls > Acceleration"), run the analysis, then view the RMS result of the acceleration. 

John

[FakeCaptainGabriel]

Hello,

I understand but that is not actually what i want.... the Grms is the overall energy or acceleration level of random vibration and is calculated by taking the square root of the area under the PSD curve. 

I have highlighted it as shown below in the image what i had intended to find:

I have got a random profile like this :

 

I wish to calculate the Grms (energy level) for this random profile and i think nastran does not do it so is there a way to calculate it?

Thanks

Gabriel

[John_Holtz]

"RMS OUTPUT" is the square root of the area under the curve created by all "PSD N" results. (In other words, graph the displacement/acceleration/stress/etc. "PSD N" for some node, calculate the area under the curve, then sqrt root, and that is the RMS OUTPUT value shown for that node.)

If the model was one node, the result in Nastran would equal the Overall Grms listed in the table. When the model has 2 nodes and each node is vibrating at a different acceleration, you need to find out how to use those results to calculate an Overall Grms. (Is it mass based? Time based? Straight average of the RMS? Something else?)

You should also check the output file (.out, located in the folder with the "model name > InCAD > FEA") in case some overall results are listed there.

John