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Merula

Shape (?) Optimization for 1D Elements

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Hey guys,

 

I was wondering if it is possible to setup the following optimization problem.

 

Lets say I have a set of nodes and bar elements. This framework has some loads and boundary conditions.

I am not sure if the node position of each node is optimal regarding compliance.

I would like to define "shapes" for the nodes where I can set some pertubations e.g. Node x can move in a sphere of radius y.

 

I have not seen this kind of optimization although I think it must be possible from an algorithmic point of view. Any suggestions?

Thanks!

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Some update:

 

I tried with a simple beam but the node movement is not following the spherical/cylindrical coordinate system. 

 

I will share my latest findings soon. 

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It could also be a cube, if the spherical movement is the problem.

I just can't see how I can implement the optimization setup (i.e. the design variables )

 

Best regards,

Merula

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Do I have to use morph volumes for this? I would like to just simply define that each node can freely move in x y z within a certain range. Minimizing the stress is the objective. I share a model file, where I have a simple beam setup where I would guess that a symetric design would be optimal.

I stuck at defining the shapes.... I've learned that free shape is not possible because I have no 2d/3d elements

 

Best regards,

Merula

beam.hm

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@Merula

 

Sorry for a late reply,

 

You are right, shape optimization is not possible with 1D elements. You need to model as either 3D or 2D. So I created a 3D model with a layer of 2D skin and used shape optimization to accommodate all Dofs,

 

Unfortunately, I don't have the mode with me. 

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I digged on this a little deeper and found a way to optimize 1d elements....

it is possible if you choose freehand under morphing and save the shapes after having changed the node positions.

 

Best regards,

Merula

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@Merula

 

I agree, but whatever you get is a concept and this needs to be fine-tuned with gauge optimization, maybe?

 

Apart from that, the results need to be validated with 2D/3D elements, as the number of Dofs will be different. 

 

The shape on optimization level is not supported for 1D elements. 

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@Prakash Pagadala

Yes, this is a concept as it does not change the shape of the actual 1d elements but the location of the linking points, but nevertheless important when you come from a topology optimization and want to fine tune the reconstructed results (when using simple bars for example).

A gauge optimization would be the final step.

 

Best regards,

Merula

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Hey guys,

 

what do you think of the result I got for the CClip.

I saw it is not a symmetric result although the input and loadcase is symmetric. Ignore the buckling constraint for now.

My question is: Is this procedure correct? The compliance is better than with topology optimization.

I attached the following results:

1) Input Deck of the topology optimization (modified version of the cclip tutorial): cclip1.fem

2) Result of the topology optimization (modified version of the cclip tutorial): cclip1_des.h3d

3) Input Deck of the Shape Optimization ShapeOptimization.fem

4) Result of the Shape Optimization ShapeOptimization_des.h3d

 

Best regards,

Merula

ShapeOptimization_des.h3d

ShapeOptimization_des.fem

cclip1.fem

cclip1_des.h3d

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