Change material properties at a specified step
Change material properties at a specified step
(OP)
Hell,
I want to change the material properties in my model at the third step.I know that i can use either USDFLD subroutine or *Field keyword option. Since i am not familiar with the USDFLD subroutine i chose the * field keyword. That is what i did
*Material, name=Material-1
*Elastic, dependencies=1
3e+06, 0.3, , 1.
300000., 0.3, , 2.
** where the first value of Young's modulus should be used in the first and the scond step, while the the second value should be used in the third step.
*Amplitude, name=step
0.,1.,1.,1.
*Initial conditions, type = field, variable = 1
name of node set,1
** since i want to change the Young's modulus in the third step
*step, name=step-3
.....
*field, variable=1, amplitude=step
But unfortunately it did not work, i do not know why, i read many posts about how to use * field variable to change the material properties, i read the manual. but i do not know why it did not work.
I wish any one send my the input file for a very simple model just one element and change the properties of that element at any load step.
I attached the input file, please help me
I spend almost 2 weeks to solve this problem
Thank you.
Mohamed
I want to change the material properties in my model at the third step.I know that i can use either USDFLD subroutine or *Field keyword option. Since i am not familiar with the USDFLD subroutine i chose the * field keyword. That is what i did
*Material, name=Material-1
*Elastic, dependencies=1
3e+06, 0.3, , 1.
300000., 0.3, , 2.
** where the first value of Young's modulus should be used in the first and the scond step, while the the second value should be used in the third step.
*Amplitude, name=step
0.,1.,1.,1.
*Initial conditions, type = field, variable = 1
name of node set,1
** since i want to change the Young's modulus in the third step
*step, name=step-3
.....
*field, variable=1, amplitude=step
But unfortunately it did not work, i do not know why, i read many posts about how to use * field variable to change the material properties, i read the manual. but i do not know why it did not work.
I wish any one send my the input file for a very simple model just one element and change the properties of that element at any load step.
I attached the input file, please help me
I spend almost 2 weeks to solve this problem
Thank you.
Mohamed





RE: Change material properties at a specified step
Part-1-1.Nall instead of Nall
because the node set Nall was defined in the Part module. Conversely, had the node set been defined in the Assembly module, Nall would have worked out just fine.
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RE: Change material properties at a specified step
I used the node set as you suggest, since i made this node set in the part module (Part-1-1.Nall) instead of Nall, but it did not work also.i.e., Young's modulus does not change in the second step.
I repeat the same model again, and make the node set in the Assembly module, so this time i can use Nall as the name of the node set,i still could not change Young's modulus in the second step.
I wish you have time and help me. I read the manual (predefined field) and read some posts.
Again, my objective is to change young's modulus in the second step. i defined young's modulus as function field variable, then i change this field variable in the second step using *field, variable=n option. i attached the input file, so you can check it again. Thank you in advance.
RE: Change material properties at a specified step
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RE: Change material properties at a specified step
In the step module, i requested output for FV. but in the visualization module , i could not plot it.
[b][u]So, please tell me how can i check the value of the field variable in the viewer.
Your suggestions and help are greatly appreciated. i am looking forward to hearing from you. Thank you so much.
RE: Change material properties at a specified step
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RE: Change material properties at a specified step
I plotted the FV, i found that it is zero in both step one and two. I want to tell you that step one is solved in one increment as well as step two.
I sent you the input file, please run it and tell me what should i do to overcome this problem.
Thank you so much. Your suggestions are highly appreciated.
Thanks
RE: Change material properties at a specified step
In Abaqus manual, section 33.6.1, It gives an idea about how to change Young's Modulus during the time step from and initial value 30E6 to final value 35E6. this is the idea.
"Define an initial condition to specify the initial value of field variable 1 as 1.0 for a node set. Then, define a predefined field variable in the analysis step to specify the value of field variable 1 as 2.0 for the node set. Young's modulus will vary smoothly over the course of the step as the field variable's value is ramped from 1.0 to 2.0 at all nodes in the node set".
*Material, name=Material-1
*Elastic, dependencies=1
**E, new, , FV1
30E6,.3, , 1
35E6,.3, , 2
** and then
*Amplitude, name=myAmp
0.,0.,1.,1.
*Initial condition, type=field, variable=1
name of the set, 1
*step, name=step-1
......
*Field, variable=1, amplitude=myAmp.
name of the set,2
I try to follow this idea on a very simple model, but it did not work.
I wish you help me and make a very simple model under uniaxial compression or tension , and send it to me.
thank you.
RE: Change material properties at a specified step
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RE: Change material properties at a specified step
You mean my file is working? I cheeked the LE, and the U , at the end of step one and step two, they are the same, and since the model is under load control and the Modulus of elasticity should be smaller in the second step, so the displacement and LE should be bigger in the second step compared to the first step. so how come the file is working and the field variable changes as required. please give more details.
Thank you for your patience.
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RE: Change material properties at a specified step
suppose you squeeze two materials under certain amount of load, one of them is stiff (high Young's modulus), while the other is not stiff (Low Young's modulus). You will find that the displacement in the soft material is bigger than the stiff material, right?
Now in my model, i am trying to decrease the stiffness in the second step, almost (1/100) of that in the first step, Hence the displacement at the end of step one should be smaller than that in step 2. but as i told you they are the same, which means that there is no change in stiffness in the second step.
I do not need to plot x-y curve, I can compare the values of the contour plots at the end of step one and step.
Thank you so much.
Your suggestions are appreciated.
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RE: Change material properties at a specified step
The graph you sent looks great, it seems that the stiffness changed in the second step as required. could you please send me the file that you run and got that results.
I run the model that i sent you whose name is (Job-1-sent-jop), and this is the x-y plot for the E2 at node 85. the strain is constant at the end of step i and step 2.
Thank you for your patience.
RE: Change material properties at a specified step
In the previous post i sent you only the E22, and make comments on your results, please read the previous post also. i think your input is different from my input file. Here i attached a graph for FV, E22 and the input file that i run and gave me the results that i sent you.
Thank you.
RE: Change material properties at a specified step
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RE: Change material properties at a specified step
in a previous post you told me (Your file (working) is attached. Field variable changes as expected. ), I downloaded the file in that post, I run it and i did not see any thing new.However, the graph you sent looks great and reasonable. did you get this result from that input file that i am talking about. or changed the input file?
Send me that input file that you run and got that results please. I start to have doubt about my software!!!
Thank you very much.
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RE: Change material properties at a specified step
I run the input file which you sent(Job-1-sent_jop). I checked the FV and E22 at node 85. please see the attached file.
I really do not know what is wrong. i can not find any explanation why your results are different from my results, although both of us run the same input file.
Please be patient for one more time. I know that i disturb you very much. forgive me.
Thank you so much
RE: Change material properties at a specified step
Thank you
RE: Change material properties at a specified step
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RE: Change material properties at a specified step
RE: Change material properties at a specified step
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RE: Change material properties at a specified step
RE: Change material properties at a specified step
RE: Change material properties at a specified step
RE: Change material properties at a specified step
Now, assuming you ran the INP I sent you and opened the ODB generated by the same INP, then I am clueless! You "seem" to be plotting variables correctly, unless there is something odd that you are doing in this stage. Difference in hardware/OS can not explain such an enormous difference!
For some inexplicable reason, your field variable value is not changing. Try the attached INP; its slightly modified.
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RE: Change material properties at a specified step
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RE: Change material properties at a specified step
Regarding Checking the verification, actually i did not run ABAQUS verification.
RE: Change material properties at a specified step
I run ABAQUS verification, and this is the verify.log file. i saw that there is a problem with user subroutine, because there is no FORTRAN compiler. Also ABAQUS could not locate the C++ compiler.
Please check it for me, you might see something i did not see.
I run the input file you sent me last time, but nothing change. i still see the FV is constant from the beginning to the end of the analysis. and the displacement is the same at the end of step one and step two.
Please advise me.
Thanks
RE: Change material properties at a specified step
The problem is running the input file from the CAE. When i run the model without CAE, it works perfectly.
But Again, you gave me the idea, thank you very much.
I might need you help later, because you when i solve a problem, soon i find another problem. so how can i reach you?
Thank you again.
RE: Change material properties at a specified step
Like other experts, I will be available here on this group. There are other groups: Yahoo Abaqus users group, Simulia customer website, Polymerfem, imechanica - which will be of help too.
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RE: Change material properties at a specified step
Thanks
RE: Change material properties at a specified step
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RE: Change material properties at a specified step
RE: Change material properties at a specified step
I need your help again.
My model composed of 10 Rock layers of different material such as Sandstone, Coal, .... etc. You know that, i want to change the material properties of a set in my model. This set involves 3 layers( for example Sandstone, coal, and shale). You know i will use *field, variable option.
I am confused about the number of field variables. Are they one or three?
That is what i did
*Material, name=Coal
*Density
2.61,
*Elastic, dependencies=1
2.592e+07, 0.18, , 1.
648000., 0.18, , 2.
*Material, name=Sandstone
*Density
2.61,
*Elastic, dependencies=1
2.592e+07, 0.18, , 1.
648000., 0.18, , 2.
*Material, name=Shale
*Density
2.61,
*Elastic, dependencies=1
2.592e+07, 0.18, , 1.
648000., 0.18, , 2.
And then i used this command.
*Filed, variable=1
(name of the set which contains the 3 layers), 2
is it correct?
or i need to define 3 field variable, like field variable one for Coal and field variable 2 for Sandstone and field variable 3 for Shale.
Which one is correct? i am confused.
RE: Change material properties at a specified step
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