Optistruct
Altair EmployeeHi,
I wanted to check, when I run optistruct for topology optimisation, I receive a message after 30 iterations that maximum iterations has reached, and design is infeasible.
What do I do from here, Can I increase the number of iterations.
Answers
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Hi SUf92,
Please refer to the below Tip and Trick:
http://www.altairuniversity.com/wp-content/uploads/2015/10/Design-iteration_increase.pdf
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Hi Prakash,
Thank you for helping me, also I was told to do UNIT CONSISTENCY CHECK.
How do I do that?
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Hi,
That is you have to take care. Maybe the below can be a little help for you...
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Hi Prakash,I have to do topology optimisation on rear bulkhead plate, from last years design I ran the analysis to find compliance, I put the compliance values and I tried two different objectives but I am not able to get the correct results, I do not know what to do anymore, I have tried everything there more ways that I have tried but still I am failing to get the results. I have uploaded 2 files. When you have time can you please have a look and tell me what I can do. Also my team manager wants me to use Extrusion as one of the design variable for water jet cutting and Draw design variable for CNC, and I do not know how to use either, when I do I do not get any results.I also also uploading a picture of the final design from last year so that you can have a better understanding of what it should look like.
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Hi,
What is the unit system you are using for your model?
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I can see a huge violation in constraint values. Can you please explain on how do you came up with compliance constraint values?
FYI
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Hi Prakash I did an analysis on the previous bulkhead that was designed, and from the out. file I found these constraint values
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Hi,
I am attaching the files that I got this information from
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The forces and length are in N and mm, while the material young modulus is in MPa, and density is in t/mm^3.
Is this something that I am doing wrong, also how do I set which units I want Hypermesh to be in.
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Hi Prakash,
I think my units were not correct. I changed my units, and I ran the optimisation again. I believe that I am getting close to the results but I am not sure. I still need to make improvements and if you have a look at the attached files and tell me what I could do to make it better. I think I should use the draw or extrusion function but I don't know how to use them properly.
Regards,
Sufian
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Well, I was trying with volume fraction and compliance with extrusion. I got some results.
<?xml version="1.0" encoding="UTF-8"?>
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Hi Prakash,
Can you tell me how to use the Draw and Extrusion variables, I don't understand how to use them. If you can make a video or something.
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Also the results you got, was it from the latest files that I uploaded?
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Go to Extrusion panel and select the node path along the thickness of the component.
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Do I select twist or no twist, and then it asks me. For the no twist it is only primary path but for twist it is primary and secondary.
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Instead have a weighted compliance response as objective and volume fraction as constraint.
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But then I don't know what value to put for the upper bound for volume fraction.
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Hi Prakash,
This is the result I got from using Mass fraction as objective and Compliance dconstraints. I used extrusion with twist.
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Can you keep the iso contour threshold value to say 0.3-0.4 and see the results?
Also, why you had twist for extursion, I dont see any twisty shape in your model. So having twist may not help in your case.
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How do I set the threshold value?
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Goto Iso panel (shown in red in the image below) and change the value.
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I did it with no twist and also with Draw option. But why is it removing material from
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I set the threshold value, and this is extrusion with no twist. But again why is it removing material from those areas.
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Also this is the result I am getting with the Draw option. I uploaded a picture of the front and back view. Why are they different?
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Try this:
1) Have Weighted compliance as objective and volume fraction as constraints (upper bound say 0.6 and lower bound 0.3)
2) Have a minimum and maximum member size in your topology model (topology>> Parameters)
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<?xml version="1.0" encoding="UTF-8"?>
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What values do I put for the minimum and maximum member size, and with these parameters should I use extrusion.
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MINDIM atleast 3 times the average element size and MAXDIM should be 2 times the mindim.
Yes you can use extrusion.
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By element size do you mean the mesh element size? Because in that case my mesh element size 4, so my MINDIM will be 12 and my MAXDIM will be 24
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Hi Prakash,
This is the result I am getting when using parameters. I set MINDIM to be 12 and my MAXDIM to be 24.
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