elastic-plastic material 2

[nicolasdegand]

Hi,

I'd like to use an elastic-plastic material. I define as

-elastic: young modulus and poisson's ratio (217460 N/mm2 and 0,298)
-plastic:yield stress and plastic strain (258N/mm2 and 0)

But I'd like to extract the values as elasto-plastic behaviour so define the gradient of the tangent of the curve in the plastic behaviour. So, to have a linear behaviour until the yield stress and than a gradient of 3% of the young modulus in the plastic part.

How to do?

I tried to define in "plastic">suboptions>rate dependent>hardening>yiel ratio>

Yield stress ratio Eq plastic strain rate
258 0
300 6500 (+/-3% of E)

But it doesn't work!

Thanks a lot,

Nico

 

[mrgoldthorpe]

Nico,

3% of E is 6523.8 MPa. So yield stress at a plastic strain of 1.0 is 258 + 6523.8 * 1 = 6781.8 MPa

So you need in the .inp file:

*MATERIAL
*ELASTIC
217460.0 , 0.298
*PLASTIC
** yield equiv. plastic strain
258.0 , 0.0
6781.8 , 1.0

Note that 2nd parameter is not equivalent plastic strain *rate", but just equivalent plastic strain.

MRG
p.s. You have asked a lot of questions in this forum recently. It would be nice if you thanked those who have helped you :->

 

[nicolasdegand]

Yes, of course MRG, I'm sorry!

I can thank a lot to all people who answered to my questions. You know, I begin to use Abaqus and try to do it alone is very difficult! So, it is impossible for me to answer to the different questions. But in a few weeks, it would be possible!

and thanks to you, MRG!!!

 

[johnhors]

Nico,

I think what MRG really meant by thanking people is awarding them a star with the "Thank ******** for this valuable post!" clickable text under everyones post!

 

[Drej]

As an addendum to previous comments on this, the OP did actually put a "thank you" in their original post. If posters want to give stars in return for helpful answers, then they should do so based on their own judgement of helpfulness for each post. They shouldn't feel emotionally blackmailed into giving stars for random posts which they themselves do not find particularly helpful -- or posts which just happen to point out that they should be thanking people by giving them stars... Amen.


------------
See faq569-1083 for details on how to make best use of Eng-Tips.com

 

[mrgoldthorpe]

Actually, I didn't mean giving stars in my post. I'm a bit too old for that. Though I see that recent threads started by Nicolas have been peppered with stars!

It's just that Nicolas has been particularly demanding of the board, particularly in posing the questions at times! But that is perhaps a cultural issue. I just wanted to point out that the effort people put in is all for free. It is nice to receive a thank you.

Actually, what I dislike the most are newcomers who ask a question, then never let us know how they get on when they receive replies.

 

[nicolasdegand]

I think that I have to intervene.

It is entirely my fault. Stop this new posts about that problem. I neglected this point of thanks with stars. I just thanked in my questions. I learned something and I thank you a lot for this. I won't forget it in future. This forum helped me a lot in my work and answered to a lot of my questions. I understand that people like to receive a thank you, that's normal!


So, mea culpa!

nico

PS:I don't think that this forum is a good place to some "special"(cutlural) problems. If people make a mistake, it is fine to signal it and people are sufficiency civilized and grateful to understand and react about it!


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