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#1 2020-09-06 21:30:45

tpa
Member
From: Denmark
Registered: 2009-04-14
Posts: 50

Data for elasto-plastic analysis of steel

Hello.
Is there any recommended sources to find recommended values to use for true stress-strain curves (TRACTION) or fitting parameters for such curves to use with ECRO_PUIS or ECRO_LINE. I am mainly considering stainless steels.
I will appreciate any proposals.

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#2 2020-09-07 15:53:41

mf
Member
Registered: 2019-06-18
Posts: 118

Re: Data for elasto-plastic analysis of steel

Hello,

there are over 2500 different kinds of steels, a good percentage of it is considered 'stainless' (I do not know the exact number, but it should be somewhere in the hundreds. Also, 'stainless' is a not very exact definition). So, there is not one single source for data. In most cases, you will only find engineering stress over strain. So you would have to calculate true stress yourself.

So which steel in which heat treatment condition shall it be? Maybe I can help.

Mario.

EDIT: also, you will have to 'design' the input data yourself. That is, separating elastic from plastic part of the curve.

Last edited by mf (2020-09-07 15:55:17)

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#3 2020-09-07 20:18:47

tpa
Member
From: Denmark
Registered: 2009-04-14
Posts: 50

Re: Data for elasto-plastic analysis of steel

Hi Mario. Thank you for your response. I have not so much experience with elasto-plastic analysis of stainless steel so my intention was to see if I could recreate the behavior reported in this article: doi.org/10.1016/j.net.2020.07.014 with AISI304 or AISI316, Both seem to be of the L quality, eg. 1.4307 and 1.4404 resp.

In the past I have used code-aster for plastic analysis of copper stuctures with some succes but then I had to calibrate the plasticity curves for the specific material with experiments.

Especially considering the much more common interest for plastic analysis of (stainless) steels, I was thinking that somewhere there might be tabulated values for standardized conditions as exist for engineering yield and tensile stresses.

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#4 2020-09-07 21:03:06

mf
Member
Registered: 2019-06-18
Posts: 118

Re: Data for elasto-plastic analysis of steel

Hi,

ok, I see. The L variants are lower in carbon and although the chemical composition depicts a lower value for C in the paper, it doesn't have to be a 304L or 316L (it could be a coincidence, I am sure the L variants require a different production route..or at least additional steps). The paper also doesn't say 304L or 316L, does it?

However, I will see what I can find. I am sure I have data for at least 304L, but I am not sure if I am allowed to pass it on.

Do you mind if I send you a private mail?

However, I will come back to you,

Mario.

Last edited by mf (2020-09-07 21:04:18)

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#5 2020-09-07 22:21:23

mf
Member
Registered: 2019-06-18
Posts: 118

Re: Data for elasto-plastic analysis of steel

Hi,

ok, I found some open-source data for both materials, there is quite a lot around. I have data for 316L, but I cannot pass that on. Please delete the blanks in the links below (not allowed to post links).

304L:
h ttps://www.researchgate.net/figure/Stress-strain-curve-for-304L-stainless-steel_fig1_266328686

316L:
h ttps://www.researchgate.net/figure/Engineering-stress-strain-curves-for-AISI-316L-stainless-steel-and-Ti6Al4V-alloy_fig2_303369275

As you need digitized values of these curves, I recommend this neat program for digitizing these curves. It runs on Java, so it's platform independent:
h ttps://sourceforge.net/projects/plotdigitizer/

From there on, you can calculate true stress via the well known formulas.

Mario.

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#6 2020-09-08 07:06:54

tpa
Member
From: Denmark
Registered: 2009-04-14
Posts: 50

Re: Data for elasto-plastic analysis of steel

Thank you very much. Especially the second article gives some food to thoughts, considering in which condition the material is. I also appreciate the link to the digitizing program. Best regards.

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#7 2020-09-08 12:20:15

GXA_William
Member
Registered: 2016-04-30
Posts: 48

Re: Data for elasto-plastic analysis of steel

Greetings tpa.

Three other resources which we use for material data are Matweb, MatDat and MMPDS.  The MMPDS resource is expensive; you can find an open source version of MMPDS, it is older but still contains valid data; the older version is named MIL-HDBK-5G (or H revision).

The two websites (Matweb and MatDat) provide some information with basic registration.

We use these three resources in our professional work, so we pay the fees, but the open source stuff might be a benefit to you.

A small note from my experience - while you will find a fair amount of "published" data for "stainless" steels the data is often minimal and you may have to perform in house testing.  As Mario mentioned, there is not one type of "stainless", this is a broad category and the range of applications is large, so most companies keep this data confidential.

-William

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#8 2020-09-08 15:32:26

mf
Member
Registered: 2019-06-18
Posts: 118

Re: Data for elasto-plastic analysis of steel

Hi William,

you are absolutely correct thanks. I did not look in the MIL-HDBK.

Tpa, if you need it, I can send it to you but they are quite big (Rev H = 43Mb, Rev J = 88Mb). Do have an ftp or sharepoint-link you can send me via email?

Mario.

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#9 2020-09-10 06:54:29

tpa
Member
From: Denmark
Registered: 2009-04-14
Posts: 50

Re: Data for elasto-plastic analysis of steel

Thank you for all your help. From the references I have been given here I have learned about the Ramberg-Osgood equation which seems to be a commonly applied model. I also learned that life is simpler when the plastic work curve is generated on a epsilon(stress) function rather than stress(epsilon) and third lesson is that even conditions after the necking occurs can apparently be handled and fourth lesson is to be picky with regards to parameters as they depend on the state of the material - e.g. cold drawing and heat treatment conditions. Fiifth and foremost lesson is that You, Mario and William are very helpful.

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#10 2020-09-10 12:14:09

mf
Member
Registered: 2019-06-18
Posts: 118

Re: Data for elasto-plastic analysis of steel

Hello,

you're welcome. Yes, austenitic stainless steels are very prone to cold work due to their low stacking fault energy. In fact, in many stainless steels cold work is the only means of improving their mechanical properties.

M.

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