×
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

Confusing behaviour of the beam model

Confusing behaviour of the beam model

Confusing behaviour of the beam model

(OP)
Hi,

I have found myself in a quite confusing situation.
My beam model does not behave as I expected.

I included 3 photos to show the model. Basicly the only difference between them is the diameter of lateral support (the shortest section in the model, the changes in diameter are visible, thickness of this sections remain the same).
When I decreased the radius of this lateral support stresses level is also decreasing. Comparing the size of the support 25(radius) (186MPa) & 10 (150 MPa) & 20 (195 MPa).
Why for the smallest tube the stresses level are the lowest?
Can you help me to understand this problem is it "normal" or is it something wrong with my model?

RE: Confusing behaviour of the beam model

You are post-processing the point2 combined stress.
When I post-process stress on beam elements I take the max (Abs) of these four output vectors:

EndA Max comb stress
EndA Min comb stress
EndB Max comb stress
EndB Min comb stress

Try to post-process like that and see if results become as you've expected..

Seif Eddine Naffoussi, Stress Engineer
www.Innovamech.com
33650 Martillac û France

RE: Confusing behaviour of the beam model

(OP)
The stresses distribution when using

EndA Max comb stress
EndA Min comb stress
EndB Max comb stress
EndB Min comb stress

is the same so this won't change anything.

RE: Confusing behaviour of the beam model

I think it is about flexibility of the assembly.
You can see that the stress distribution is transferred to the medium section which is not the case in your first case.

Seif Eddine Naffoussi, Stress Engineer
www.Innovamech.com
33650 Martillac û France

RE: Confusing behaviour of the beam model

the load in the reduced member seems to be falling, but the load on the "elbow" (the sloping member) seems to be increasing. it looks to me as though the stiffness of the model is redistributing the reactions away from the lateral brace (as it's stiffness is being reduced).

i'd look at where the load is going (rather than the stress) ... internal shears and bending moments should help you understand what's happening.

another day in paradise, or is paradise one day closer ?

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

White Paper – Your Construction ERP RFP Checklist
Selecting business software for a medium to enterprise-sized construction concern is extremely challenging in large part because most enterprise resource planning (ERP) suites originated in the world of repetitive manufacturing and are therefore a poor fit for a project and asset-centric business. However, midsize to large contractors need the predictable, auditable processes that ERP delivers. Download Now

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