topology optimization with multiple load cases
Altair Employee
Dear all,
I am running a topology optimization, but I want to consider multiple load cases at once and not each one separately.
Is that possible? How can I insert all the load cases (five) and only solve one optimization considering all of them?
Thank you in advance
Answers
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Hi Mike,
What is the objective and constraints you want to use?
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So far I used min compliance as objective function and volume fraction as constraint
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Hi Mike,
You can use Wcomp (Weighted compliance) and select all loadsteps along with volume fraction. This way you are considering all loadcases.
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Thank you!!
So I create the response 'weighted compliance' and, in my case of 5 load cases of equivalent importance, I set each weighting factor to 0.2, correct?
And then as usual in the objective I set minimize the weighted compliance, correct?
Thank you!
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Mike,
See the equation below for WC, where W is the weight factor.
If your weight factor is 0.2, the compliance considered for load case1 for example will be 0.2 times of actual compliance.
<?xml version="1.0" encoding="UTF-8"?>
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So if I want all the five load cases to have same weight, what should I set the weight factors to?
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Set the weight factor to 1
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What if I want to minimize the mass as objective function? Is it possible to still add multiple load cases?
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Mass response is subcase independent.
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Thank you for your answers...last question.
What would be the best approach if I want to:
- minimize the volume of the model (or the mass) with multiple load cases and
- and as constraint use the static stress
Is there a possibility? Or how would you suggest to run the optimization?
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Hi Mike,
Stress as a global response with mass or volume response is not recommended
from OptiStruct help:
It is not recommended to use the global stress constraint along with a mass/volume constraint. The constrained mass/volume may not allow the stress constraint to be satisfied.
To start of with, Try with Complinace as objective and volume fraction to get a concept and further you can fine tune the design for stress and other parameters.
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Perfect thank you very much!!
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Hi,
I have a design that is made of several 1D bar elements (about 15) of circular cross section.
I now want to perform a size optimization on the cross section radius of these beams.
I have multiple load cases (3)!
I would like to minimize the mass and subject the stress.
How should I do that?
Thank you
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Hi Mike,
You can select loadsteps when you create Stress constraint.
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