operational vibrations with radioss

Altair Forum User

Hey Folks

I would like do a vibration analyses on a plate (made of Steel), with encastered boundarys and a dynamic force which is attacking in the middlepoint. The force excitiation is harmonic (sinus, cosinus Fourier ect.) I would afterwards display the 'Time - Displacement - Graph' from one Point in HyperGraph and the whole displacementfield in Hyperstudy.

To build up the modell is my biggest problem. I have tried the 'Transient (Modal)' loadstep. I have used DAREA as force and the excitation was given by a TABLED1 (importet). I put this together with a TLoad and created a TStep (Time). The Solution was not that good because the results were very shaky.

My Questions are:

- is there any possibility to perform a operational vibration analyses with Radioss in Time domain

- if Yes, which kind of loadstep must I use to get a time - harmonic vibration (I have found nothing how to use TStep Fourier)

- can I define the excitation via a 'Curve' or is TABLED1 the only way?

- which kind of load must I use (TLoad/RLoad/DLoad)

Thank you for your help.

With kind reagards

Alex

Altair Forum User

Others have a lot of good material.

Altair Forum User

Hi Alex,

 

I want to answer your question as I can:

 

1- Yes you can perform operational analysis in RADIOSS. You can use SPCD as a dynamic load to define acceleration, displacement or velocity to your model. But you must define this type in TLOAD entry.

 

2- The TSTEP is your time domain. You should define your analysis duration on it. For example if you looking for 3 second in your analysis, you can define it 10 as 'N' and 0.3 as 'NDF'.

 

3- The RADIOSS can understand your analysis in time or frequency domain by TABLED entry. So you should define it with your dynamic load in TLOAD.

 

4- In transient analysis frequently TLOAD is using. But you can look on help another load types. I don't know everything about them.

 

Thanks,