Optistruct- HM 2017 - CNTNLSUB - Non-linear quasi-static
Altair EmployeeHi,
i modelled two bars as seen in the picture. The blue one is at the left end and the yellow one on the right end fixed with constraints.
One force (1st_Force in green) is defined on the right end of the blue bar to the bottom and the other one (2nd_Force in orange) at
the left end of the yellow bar to the top. Additionally a contact have been modelled between the two bars.
Now i wanted to create two subcases. The first one (1st_Force as seen in the picture) should bend the blue bar against the yellow one. The second subcase should start with this initial bending position and bend the yellow bar to the top. So the CNTNLSUB box is checked and the first force is choiced as the SCID.
The problems are the following.
1. There aren´t any differences if i check the CNTNLSUB box in subcase two or not. The results in Hyperview are exactly the same.
2. The initial position of the second subcase isn´t the end position of the first subcase.
Thank you very much for helping.
Answers
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@N_R You need to change D field of SPC to F so as to get displacement from susequent subcase.
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To change field from D to F kindly follow this procedure.
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Thanks for helping.
I found the procedure and changed the field of the SPCs of the first subcase to fixed (f). I controlled that at the card image of the constraints.
The second subcase got an own load collector with the same SPCs except for the option fixed so that this SPCs have got the field 'd' at the card image. All SPCs are still at the end of the bars as described at my other post.The simulation progress is sucessful, but the results aren´t still satisfactory as seen in the following pictures:
The first subcase - in which the constraints are set to 'f'- doesn´t work. A displacement is shown in the first step, but if i choose another step there isn´t seen anything.
After that i tried the fixed SPCs at other models and get the same. Do i have to change another option??
<?xml version="1.0" encoding="UTF-8"?>
The second subcase still working as before. No displacement and stress at the starting point.
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@N_R You need to apply F field for second load case.
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@Nachiket Kadu
Thanks for your answer.I changed now the F to the second SPCs. Now the results are the same as at the beginning. So the subcases works, but the second
subcase don´t start at the beginning of the first one.
Maybe you can check my model? It´s a very easily, non complex model of the two bars.
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@N_R Review this file.
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Tell me is that what you looking for?
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The second subcase start at a non-bending/displacement point. This isn´t that what i´m looking for.I want to have the first subcase as a prestressed/pretensioned point and extending this situation with other forces/subcases.
So the subcases should act in a row and not parallel: The forces of the first subcase should act as the first. After the deformation
of the objects/solids as a result of the forces of the first subcase, the second force should be act on this deformed state: For
example maybe redeform the objects/solids from the deformed state to another deformed state.
For this case i want to analyze the system with its stressing and deformation.
Thank you very much for your effort.I hope that the sketch is understandable;)
<?xml version="1.0" encoding="UTF-8"?>
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@N_R you change the contact to continuous sliding and then try.
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Altair Forum User said:
The second subcase start at a non-bending/displacement point. This isn´t that what i´m looking for.I want to have the first subcase as a prestressed/pretensioned point and extending this situation with other forces/subcases.
So the subcases should act in a row and not parallel: The forces of the first subcase should act as the first. After the deformation
of the objects/solids as a result of the forces of the first subcase, the second force should be act on this deformed state: For
example maybe redeform the objects/solids from the deformed state to another deformed state.
For this case i want to analyze the system with its stressing and deformation.
Thank you very much for your effort.I hope that the sketch is understandable;)
<?xml version="1.0" encoding="UTF-8"?>
Hi
I forgot to mention that try running that file in optistruct 2017.2.1 as 2017.2.2 is not taking contact properly.
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Hi,
Even I tried with model , I too don't find any continuation of forces/displacements from 1st subcase to 2nd subcase.
With and without CNTNLSUB produced same results???
Can any one help us with the changes to the file to have a better understanding of CNTNLSUB card usage...
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Hi @Prakash Pagadala, Thank you
I could see that the end of case 1 is beginning of case 2. ( provided the constrain missing @ the end of beam)
but my doubt is whether the applied forces in 1st case carried over to the second case. ?
If so the expected result is totally different for the deflection actually got (please ref to the images attached)
<?xml version="1.0" encoding="UTF-8"?>
<?xml version="1.0" encoding="UTF-8"?>
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Hi @Karthic
Sorry for a late reply. Somehow I missed this post.
Do you have the modified model for the same?
If yes, can you share the model file?
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No, Its the same model which you have used in previous post, only thing is SPC missing at the beam end.
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Thank you Prakash
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