Learning Forum

[Marcos Garcia]

Hello

I'm facing a problem in Mechanical Topology Optimization. I would like to reduce the weight of the Bracket using topology optimization in Ansys. I defined the exclusive and design regions according with the requirements I have.

The loads used for the static analysis were: Remote force and Acceleration (60g value for the whole body)

I used Level Set Method with Stress Constrain (480MPa) and Mass Retain (10-20-50%) an all the results where the same, whatever i defined as "Percent to Retain" in mass "Response Constarint", what i dont understand.

For the optimization, I used a "cubic" preform to make the optimization more powerful and get better results. The preform is shown aas follow:

The setting used:

The result was the following. As you can see, it doesn't make sense at all because every part of the model is disconnected. How could I resolve my problem and every part connected? I tried different things and noone worked correctly, I always get the same results.

I tried supressing the Acceleration Inertia force and the results were succesfull (same settings and 15% of mass retained defined). The wrong result obtained before was due to the Acceleration Inertia force? If yes, how could i make the Static Analysis if I have to use 60g value force in the model and I'm not allowed to use the Acceleration? Another question is...why there is no simetry in the optimized model if the initial geometry is simetric?

I thought about the chance of making the topology optimization without using the acceleration inertia and later, when I get the model optimized and the geometry cleaned, use this force the Static Analysis of the part optimized after the topology optimization preprocessing. Is it correct? Do you have another idea in mind which could help me?

Thanks in advance.

[John Doyle]

From the images you shared, your mesh looks a bit coarse.  I can reproduce similar result with a simple block model under acceleration load, constrained at six corners and with a coarse enough free mesh.  The fix in my test case is to refine the mesh and make mesh perfectly symetrical about the plane of symmetry of the loading.   

See screenshots below.  

 

Topo-Opt result with coarse free, nonsymmetric tet mesh:

 

Topo result with finer hex mesh, perfectly symmetric:.

[Marcos Garcia]

Hello!

I followed your recommendation and everything worked good. Thanks!

I have another question, I dont have avaliable "Retained Threshold", how could I activate that? I'm using Ansys 2023 R2 and using Level Set optimization

Regards