×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Self weight in Ansys

Self weight in Ansys

Self weight in Ansys

(OP)
Hi folks,
I have been exploring both Ansys and Staadpro. I am just curious that why is it that self weight is considered only in staadpro and not in Ansys.

Really wonderful to be part of this community.

RE: Self weight in Ansys

Ansys will consider self weight if you tell it to.

Rick Fischer
Principal Engineer
Argonne National Laboratory

RE: Self weight in Ansys

(OP)
Hi Rick,
Thanks for your reply. But I would like to know what difference it makes? Why don't we consider self weight in mechanical designs? Why do we considered self weight only in case of structures in civil engineering?

Would be greatful if I get answers to the above queries.

Thank you.

RE: Self weight in Ansys

Who says "we" don't consider self weight in mechanical designs? If its appropriate to my analysis, I include self weight. if its not, I dont. My guess is the rest of we do the same.

Ansys doesn't include self weight by default because it is a very general purpose program and geometry can be imported with random orientation. Im guessing that if it decided that global Y was up, and a part designed with global X as up was imported, an improper load would be applied that might not be obvious to newbie or casual users. I think their approach is they supply the model, but the user builds the model and runs the analysis. In any event, its easy to do with the ACEL command in MAPDL, and Workbench has a gravity load (which requires you to pick the up direction), so really its no big deal. I have no experience with Staadpro, but it looks like a dedicated civil engineering type structural package, so perhaps in that context it makes sense to include self weight by default. But the reality is that gravity is largely irrelevant to the analysis of all kinds of stuff. Is it more correct to include gravity? Yup. Is it always relevant? Nope. When you add in discretization error, variable material properties, etc, the effect of gravity gets lost in the noise.

Rick Fischer
Principal Engineer
Argonne National Laboratory

RE: Self weight in Ansys

(OP)
Hi Rick,
Thanks a lot for your detailed insights. Will explore further and revert.

Cheers!!

RE: Self weight in Ansys

I want to specify that gravity might not be the design load for mechanical purposes, but in CW it can be more than relevant. But yes, the gravity is not added by default because it is a general purpose FE software, so if you want for example to consider a different gravity value, or a more adapted direction (who said that gravity is -Z in all models?), you can do it.

More, it should reinforce the conscience about Ansys and similar software, where you control nearly everything. Even gravity. So you must have clear in your mind what you're doing.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login



News


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close