Find average stress and strain for a specified set
Find average stress and strain for a specified set
(OP)
Hello.
I need to draw the stress-strain curve for a specified set. since the model is very big, i used python to extract the S33 and LE33
I used this code to extract the S33 and LE33 for set called Coal-1.coal
session.xyDataListFromField(odb=odb, outputPosition=INTEGRATION_POINT,
variable=(('LE', INTEGRATION_POINT, ((COMPONENT, 'LE33'), )), ('S',
INTEGRATION_POINT, ((COMPONENT, 'S33'), )), ), elementSets=('COAL-1.COAL',
))
to find the average strain, i need to write the following code for a set composed of 4 elements
xy1 = session.xyDataObjects['LE:LE33 PI: COAL-1 E: 1 IP: 1']
xy2 = session.xyDataObjects['LE:LE33 PI: COAL-1 E: 2 IP: 1']
xy3 = session.xyDataObjects['LE:LE33 PI: COAL-1 E: 3 IP: 1']
xy4 = session.xyDataObjects['LE:LE33 PI: COAL-1 E: 4 IP: 1']
xy5 = avg((xy1, xy2, xy3, xy4))
xy5.setValues(
sourceDescription='avg ( ( "LE:LE33 PI: COAL-1 E: 1 IP: 1", "LE:LE33 PI: COAL-1 E: 2 IP: 1", "LE:LE33 PI: COAL-1 E: 3 IP: 1", "LE:LE33 PI: COAL-1 E: 4 IP: 1" ) )')
tmpName = xy5.name
session.xyDataObjects.changeKey(tmpName, 'Strain')
This will a problem if that set is composed of thousands of elements. Since i need to write the above code for thousands of elements, correct?
what should i do, how can i find the average of the extracted Strain and stress?
Thanks
I need to draw the stress-strain curve for a specified set. since the model is very big, i used python to extract the S33 and LE33
I used this code to extract the S33 and LE33 for set called Coal-1.coal
session.xyDataListFromField(odb=odb, outputPosition=INTEGRATION_POINT,
variable=(('LE', INTEGRATION_POINT, ((COMPONENT, 'LE33'), )), ('S',
INTEGRATION_POINT, ((COMPONENT, 'S33'), )), ), elementSets=('COAL-1.COAL',
))
to find the average strain, i need to write the following code for a set composed of 4 elements
xy1 = session.xyDataObjects['LE:LE33 PI: COAL-1 E: 1 IP: 1']
xy2 = session.xyDataObjects['LE:LE33 PI: COAL-1 E: 2 IP: 1']
xy3 = session.xyDataObjects['LE:LE33 PI: COAL-1 E: 3 IP: 1']
xy4 = session.xyDataObjects['LE:LE33 PI: COAL-1 E: 4 IP: 1']
xy5 = avg((xy1, xy2, xy3, xy4))
xy5.setValues(
sourceDescription='avg ( ( "LE:LE33 PI: COAL-1 E: 1 IP: 1", "LE:LE33 PI: COAL-1 E: 2 IP: 1", "LE:LE33 PI: COAL-1 E: 3 IP: 1", "LE:LE33 PI: COAL-1 E: 4 IP: 1" ) )')
tmpName = xy5.name
session.xyDataObjects.changeKey(tmpName, 'Strain')
This will a problem if that set is composed of thousands of elements. Since i need to write the above code for thousands of elements, correct?
what should i do, how can i find the average of the extracted Strain and stress?
Thanks





RE: Find average stress and strain for a specified set
Python string search works as following:
IF 'COAL-1' in key:
%% extract the strain here of the corresponding element
END
Make a loop over all xydata with this check. Search google for region.keys() or just keys. (I did this with history outputs, not field outputs or XY data)
grtz
bvrm
RE: Find average stress and strain for a specified set
Could you please help me more, i have no idea about python, and i do not know how to make that loop, please teach me how to make it.
Please help me.
RE: Find average stress and strain for a specified set
Are you new to this forum? If so, please read these FAQ:
http://www.eng-tips.com/faqs.cfm?fid=376
http://www.eng-tips.com/faqs.cfm?fid=1083
RE: Find average stress and strain for a specified set
I need somebody to teach me how to extract (by python) the S33, and LE33 from a set and then taking average for them then combine them to get the final Stress-Strain curve.
Thanks
RE: Find average stress and strain for a specified set
Are you new to this forum? If so, please read these FAQ:
http://www.eng-tips.com/faqs.cfm?fid=376
http://www.eng-tips.com/faqs.cfm?fid=1083
RE: Find average stress and strain for a specified set
I carried out these steps on a small model, i opened the RPY file, i found that Abaqus Uses the following commands to extract S33 and LE33 from a set called Coal-1.coal composed of four elements :
session.xyDataListFromField(odb=odb, outputPosition=INTEGRATION_POINT,
variable=(('LE', INTEGRATION_POINT, ((COMPONENT, 'LE33'), )), ('S',
INTEGRATION_POINT, ((COMPONENT, 'S33'), )), ), elementSets=('COAL-1.COAL',
))
So i can use the previous command to extract S33 and LE33.
and to get the average Abaqus uses the following commands
xy1 = session.xyDataObjects['LE:LE33 PI: COAL-1 E: 1 IP: 1']
xy2 = session.xyDataObjects['LE:LE33 PI: COAL-1 E: 2 IP: 1']
xy3 = session.xyDataObjects['LE:LE33 PI: COAL-1 E: 3 IP: 1']
xy4 = session.xyDataObjects['LE:LE33 PI: COAL-1 E: 4 IP: 1']
xy5 = avg((xy1, xy2, xy3, xy4))
xy5.setValues(
sourceDescription='avg ( ( "LE:LE33 PI: COAL-1 E: 1 IP: 1", "LE:LE33 PI: COAL-1 E: 2 IP: 1", "LE:LE33 PI: COAL-1 E: 3 IP: 1", "LE:LE33 PI: COAL-1 E: 4 IP: 1" ) )')
tmpName = xy5.name
session.xyDataObjects.changeKey(tmpName, 'Strain')
this is the problem, because if my original model composed of 10000 elements, i need to write the above Xy data for the 10000 elemnts, this impossible!!! i need to write a code to let Abaqus do loop, so i do not need to write the above code 10000 times.
could you please teach me how do that loop to get the average of the extracted S33 and LE33. right now i am reading the manual, but i need some tips. Thanks
RE: Find average stress and strain for a specified set
This is something you must be able to do on your own.
Are you new to this forum? If so, please read these FAQ:
http://www.eng-tips.com/faqs.cfm?fid=376
http://www.eng-tips.com/faqs.cfm?fid=1083
RE: Find average stress and strain for a specified set
In abaqus when the number of elements exceeds certain limit, i can not extract the stresses and strains in the elements. Now i know how to extract them from the RPY file, however i do not know how to get the average.
Thanks
RE: Find average stress and strain for a specified set
Are you new to this forum? If so, please read these FAQ:
http://www.eng-tips.com/faqs.cfm?fid=376
http://www.eng-tips.com/faqs.cfm?fid=1083
RE: Find average stress and strain for a specified set
RE: Find average stress and strain for a specified set
Anyway, why don't you just request RF and U (along the direction of the application of BC) from a node that is kinematically coupled to a the rest of the node on each platen? You could also use an equation constraint to apply the kinematic constraint. Once you get RF and U, carry out basic algebraic manipulation to get stress vs. strain (which is what you should be computing, anyway) to compare with experimental/published results.
Are you new to this forum? If so, please read these FAQ:
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RE: Find average stress and strain for a specified set
That is a good idea, i could use the RF and U in the direction of the BC to get an average stress-strain curve. so i do not need to get the average stress and strain in all elements, i can use only the RF and U.
Thanks
RE: Find average stress and strain for a specified set
That is a fundamental misconception! There is a world of difference between structural and material properties.
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RE: Find average stress and strain for a specified set
Second question, do you know a book or a paper that i can use to get more detail about that.
when i model a big structure i apply a scale factor to reduce the strength.
RE: Find average stress and strain for a specified set
Without a sound structural background, you will have little to no idea if your computational results (in a structural model) make sense or not.
Are you new to this forum? If so, please read these FAQ:
http://www.eng-tips.com/faqs.cfm?fid=376
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