Jump to content

Why is the definition of TSTEP necessary for Nonlinear Direct Transient Analysis?

Recommended Posts

Dear Support-Team,

I am currently working on a Nonlinear Direct Transient Analysis to be solved with OptiStruct. I have read in a variety of sources that for this kind of problem  NLPARM and TSTEP load collectors must be defined. I have also read that some entries made in NLPARM will override entries written into TSTEP. If this is so, why do I have to define a TSTEP load collector in the first place? Further, is my assumption correct that NINC-, DT-settings in NLPARM (also in NLADAPT and NLOUT) refer to time incrementation when performing a Nonliniear Direct Transient Analysis??


I'd be very grateful for your Help!



Share this post

Link to post
Share on other sites

First of all, thanks for your reply tinh!


I understand what you are getting at. Still, I'm not quite clear about one thing. In TSTEP I am defining " time step parameters for control and intervals at which a solution will be generated and output in transient analysis" (quote from OptiStruct Help-webpage on Bulk Data Entry TSTEP). I understand what the different parameters are meant to do (N, DT, NO and so forth). But when I define them and leave similar parameters in NLPARM blank intentionally to avoid overriding the solver won't stick to the defined parameters. For example, when I define N=1000 and DT=0.001 in TSTEP I would expect to have 1000 increments solved by OptiStruct. The Out-file shows, that a lot less increments are actually solved. Even when I put DIRECT=yes in NLADAPT to specify fixed increments.


Thinking about it, I still have a lot of stuff I am not sure about regarding HyperMesh/OptiStruct.


Maybe somebody can clear things up for me? :)

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

You are posting as a guest. If you have an account, please sign in.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...