Plastic VS Non-linear Analysis 1

I know that this is basic to some of you "excuse my ignorance".... is plastic analysis some form of non-linear analysis?

 

[FEA way]

Yes, there are 3 basic forms of nonlinearity in stress analyses:
- material - behavior other than linear elastic (Hooke’s law) - plastic, hyperelastic and so on
- boundary - changing contact conditions and follower forces
- geometrical - large displacements cause changes in stiffness of the structure

 

[ThomasH]

Well, it depends.

For steel it usually means that you include the materials yield strength in the analysis. For other materials it can mean other things. But "plastic" in a general sense usually means a non-linear analysis.

Thomas

Edit: FEA_way was slightly faster and more complete

 

[JoshPlumSE]

There is an effort to move towards some different language when talking about analysis. Let's call it the use of more "European" terminology.

LA = Linear Analysis
GNA = Geometrically non-linear analysis
MNA = Materially non-linear analysis
GMNIA = Geometric and materially non-linear analysis with the effects of imperfections.

This takes a little getting used to, but I have grown to like this terminology. I think the issue is that in the US we tend to use inconsistent or ambiguous terms that can mean different things to different people....
[ul]
[li]Non-linear analysis (without specifying what type of nonlinearity).[/li]
[li]P-Delta Analysis,[/li]
[li]2nd order analysis.[/li]
[/ul]

Also, isn't boundary non-linearity really just a subset of geometric non-linearity? Like how P-Delta is a sub-set of geometric non-linearity.

 

[chris3eb]

I tend to think of plastic analysis as being a nonlinear static (pushover) analysis. As far as I'm aware, this is usually more for understanding of the behavior of certain frames (ie which member hinges first), than as a final analysis. This may or may not be done by hand and may or may not consider the entire building, or just part of it.

And I think of nonlinear analysis as being a nonlinear dynamic analysis (with time history ground motions). This is always done with a computer. Usually some sort of linear or pushover analysis is done first to determine locations of plastic hinges.

 

[NorthCivil]

On this forum there is only two types of stupid question:

-homeowners looking for free informal structural engineering advice
-students looking for solutions to their homework problems

all other questions welcome, this one included, was a good refresher for old information i had burried somewhere in my declining memory.

thanks,
Northcivil

 

[dik]

Chris3eb:

Catch the thread: thread507-459820

Plastic design can be used for actual design and can be quite economical. Take a look at the project at:

https://www.google.com/maps/place/6500+Silver+Dart...

Dik