spring element

[ananthaces]

I have used spring element as panel pins in my analysis. But when the .nas file is written it is generating CROD card instead of CELAS2 card which is meant for spring elements. Even the spring property that i have defined is not generated. Can anybody tell me why this is happening. Thanks.

 

[Aerodesign]

Whats the software? At a guess you need to change the preferences for nastran so that the correct element types and prop sets are written.

 

[EVdave13]

I use NASTRAN for windows, which is a version of FEMAP, and have had the same problems with CBUSH elements. When I ran the analysis, it got confused about the properties I had set up and wrote viscous fluid elements in place of some of the CBUSHes. The workaround they gave me was to reassociate the property with the element before running. I haven't had the problem since, but I've only use CBUSHes 1 other time since then.

So possibly reassigning the property to the elements right before running will work.

Interestingly, it didn't happen on all the elements. It seemed to be randomly scattered among them.

 

[ThomasH]

Does the CROD instead of the CELAS2 mean that results you get is wrong? The reason for the question is that a simple axial spring can simulate a spring so to use CROD can work quite well. But if you want to use the CELAS2 element you can do this by using the DOF spring in FEMAP.

And EVdave13, strictly speaking Nastran for Windows is NOT a version of FEMAP. Nastran for Windows runs MSC.Nastran as solver with FEMAP for pre- and postprocessing. In the same manner NEiNastran has a different solver but, as far a I know, the same FEMAP for pre and post.

I don't mean to be picky but the Nastran-version closest associated to FEMAP today i probably NX Nastran. But neither of the Nastran-versions can be seen as a FEMAP-version, the two softwares work together but they don't do the same thing.

Regards

Thomas

 

[GBor]

ThomasH,

I'm with you. FEMAP is an independent pre and post processor...not a Nastran product. FEMAP has been purchase as the front end for a few versions of Nastran. This is part of the problem...make sure you are selecting the right engine in your analysis settings.

Garland E. Borowski, PE