# Is it possible to perform a Shape Optimization while maintaining constant total volume?

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Hi,

I am trying to run a model which simulates that of a cantilever beam with circular cuts designed into it at regular intervals. I have a force load applying in compression along the top edge of the beam and would like to perform a shape optimization of the circular cuts while maintaining constant volume of the model under a minimizing compliance (maximizing stiffness) objective. I've tried it a few different ways but can't get the model to converge after more than two iterations (the optimization isn't progressing very far most likely due to the strict volume constraints. So what I would like to know is if it is possible to perform a shape optimization while maintaining constant volume of the model. I understand that this may be a difficult problem for the solver as I'm asking it to make changes while perhaps not giving it room to work with. If an upper and lower bound constraint of the original volume is too tight of a constraint, how loose do I have to make the constraint to allow for a reasonable shape optimization to be performed while maintaining (mostly) a constant total volume? Thanks for your input!

I've attached the .HM file as well if you would prefer to take a closer look at the problem setup and optimization parameters.

Dylan Stelzer

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Hi,

In order to keep the same mass or volume please refer attach video.

Regards

Rahul R

mcon.swf

Dylan Stelzer likes this

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Rahul R,

I can see that you're manually creating the shape perturbations this the attached example. I forgot to mention this in my original post but I'm wondering if there is a way to translate this to a free shape optimization? Is it possible to go through the same method you've shown here? I'm going to do some personal investigating of the matter but as a "slight" solution at the moment, I am using a volume constraint with an upper and lower bound in such a way to arrive at a final shape that is within <2.5% of the original volume. I know it is not an exact solution if volume were constant but I'm using this as an estimation. Thoughts?

Dylan Stelzer

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Hi Dylan,

I dont think this is possible with free shape. Free shape generates concept shapes and this can be fine tunes using shape.

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