×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Jobs

Obtaining ultimate load using Riks method

Obtaining ultimate load using Riks method

Obtaining ultimate load using Riks method

(OP)
Hello, everybody. I am using the Riks method in order to obtain the bending moment resistance of a beam. My material is aluminium, modeled as a continuous stress-strain curve (elastic and plastic properties). If i set a load value which is large enough, do i get a proportionality factor after the analysis, which i can use to multiply the load and to obtain the ultimate bending moment? If not, how can i, otherwise, go about this?

RE: Obtaining ultimate load using Riks method

Hi,
While running (and afterwards of course), you can open the .odb and check "LPF" in history output.

LPF
Load proportionality factor in a static Riks analysis.

.dat: no .fil: automatic .odb Field: no .odb History: automatic



Cheers!

RE: Obtaining ultimate load using Riks method

(OP)
Thank you for your answer, StefCon. I am wondering what if i assume the arc length wrong? For example, i did a buckling analysis, got the critical load factor, imported the imperfection into the next model, proceeded with Riks method (i have assumed arc length 1), but i get the LPF which is extremely low, and arc length is 2,7. Could that be the problem?

RE: Obtaining ultimate load using Riks method

I haven't read it myself but I do believe that arc length can be too large. A large arc length could "miss" your highest LPF if you dont sample enough.

Are you applying the full (or maximum) load in the riks step? If so, the arc length should be smaller (like 0.01), right?

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!


Resources