Why do we simulate Tensile test ?

[farzadtb]

Hi All

I know it might be a basic question for you guys

but since I have not dealt with this , I would like to ask , we do the tensile test only when we have to know the material behavior, once we know that, why should we simulate it ? definitely we don't know the material stess-strain behavior if we have not tested if before

Thank you very much

 

[Dave442]

Hi,

When I am given uniaxial stress-strain data I will often perform a single element tension test to verify that I have defined the material model correctly in the FEA code. Takes 2 minutes and gives confidence in the model.

Dave

 

[farzadtb]

thank you, shall I ask you how do you verify that?

 

[Dave442]

Hi,

Not sure what you mean. For what I described:
[ol 1]
[li]Take the uniaxial stress-strain data which you have generated or taken from the literature.[/li]
[li]Use it to define the appropriate material model (elastic-plastic, hyperelastic etc.) in the FEA code.[/li]
[li]Perform a single element uniaxial tension test to replicate the conditions under which the test data was generated.[/li]
[li]Verify that the FEA output matches the measurements from the test.[/li]
[/ol]

Just a simple test to check a material model is defined correctly. I'm sure there are other reasons to simulate a uniaxial tension test? Maybe it is useful to people who modelling damage/failure or developing user-defined material models?

Good luck,
Dave

 

[farzadtb]

Thank you Dave

I think I need a bit more elaboration

let's say we have test results, with a yield stess at 320 MPa @☺0.02 of strain , then 500 MPa @0.1 strain and 800 MPa @2 (strain) - I know there are just three point , let's say we have a full diagram

then we do the analysis, I see the material has yielded at 800 MPa

If we assume that the correct and real UTS was 750 MPa , how am I gonna justify it with that single element analysis ??

 

[Dave442]

In that case you are not going to justify your material model???

If you define your material model using uniaxial test data and run a single element tension test, your FEA output should match your test output. If the they match, you have verified the material model. If they don't match you made a mistake defining the material model.

Dave

 

[farzadtb]

Thank you Dave, but you know that yet I have not understood you? Shall you please exemplify numerically?

 

[Dave442]

Sorry, I've explained as clearly as I can three times now.

What part does not make sense?

Dave