Effective Plastic Strain?????

[DDM84]

Hello everyone,

Can any please let me know, what exactly is effective plastic strain as I am bit confused about it.
Is there any formula for this or do we have to calculate from stress-strain data?

Thanks!!!

 

[TGS4]

You're going to have to provide some context to this question before you get any responses.

 

[DDM84]

I want to perform crash analysis in LS Dyna.
My material Aluminium honey comb block.
Since I have shell model so I am using Piecewise Linear Plasticity model in LS Dyna so in this material model I need to use Effective plastic strain values and corresponding yield stress values. Actually I am confused about what does this effective plastic strain mean? and is it possible from compression test to obtain Stress vs Strain data? which I can use for this analysis. And values from Engineering or true stress-strain curve do we have to use for such analysis?
I am preety much new in crash analysis field and finding these material properties for honeycomb is little difficult for me now. So I hope anyone with knowledge of compression or tensile test and how to extract that data from test to obtain stress-strain curve will be really helpful.

Thanks

 

[Jetgirl8]

I think that this posting on the LS-DYNA online support manual might be helpful for you:

http://www.dynasupport.com/howtos/material/from-engineering-to-true-strain-true-stress

If you are new to crash analysis and LS-DYNA, I would highly recommend getting some training form LSTC.

When the future's architectured
By a carnival of idiots on show
You'd better lie low

 

[DDM84]

@Jetgirl8
Many thanks for the link. Recently I had training for LS Dyna but finding material properties to use in those material cards is little difficult as of now cause I am trying to which test shall I perform so that I can end up with yield stress v/s effective plastic strain plot