×
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

Material nonlinearity

Material nonlinearity

Material nonlinearity

(OP)
To consider only material nonlinearity in SAP2000:

-what would be the mass source for subsequent load cases after nonlinear dead load as initial case? Two options are available, default mass source and from previous load case.

-how to find the point in which materials enters plastic state and no longer elastic? Is any plot or data produced after analysis?

Cheers,

Shoot for the Moon, even if U miss, U still land among Stars!

RE: Material nonlinearity

Plot Stress vs Time. At some point of time stress will become constant indicating material has entered plastic state.

RE: Material nonlinearity

(OP)

Quote (precast123)


Thanks for your input. In case of shell elements, what stress I need to plot against time using time history analysis? How about frame elements? To plot any value against time, then the required load case must be in dynamic state to be able to plot the stress/force vs time.

Shoot for the Moon, even if U miss, U still land among Stars!

RE: Material nonlinearity

What material non linearity you are using? Yes you have to perform time history analysis. See the attachment. Its the plot for a pipe which is axially loaded. At some point of time, the stresses becomes constant.The pipe material is High density polyethylene.

You can plot Von Mises stress.

RE: Material nonlinearity

(OP)
Most likely I'd use reinforced cocnrete with user-defined stress-strain curves. I reckon for shell and frame elements depending on the pattern of loading, different stresses vs time could be plotted other than Von Mises stress. Have you tried to plot other stresses? Currently I don't have access to SAP2K.

Shoot for the Moon, even if U miss, U still land among Stars!

RE: Material nonlinearity

I have used Abaqus for non linear dynamic analysis. For a frame member you can get results of Bending moment and manually calculate bending stresses(M/I * y) and plot them against time. I have always worked with Von Mises stress. Dint tried others.

RE: Material nonlinearity

(OP)
I reckon depends on purpose of analysis and nature of loading, various plots could b made. Since we're dealing with NL of structure, then it'd be better if stress is illustrated versus time to study at which instant the structure enters plastic state.

Shoot for the Moon, even if U miss, U still land among Stars!

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