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calculix / beso

Python code for topology optimization using CalculiX FEM solver.
GNU Lesser General Public License v3.0
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Some questions about examples #7

Closed 461353349 closed 5 years ago

461353349 commented 5 years ago

I have two questions: 1、All the examples show that non-design-space material is same with design-space. Non-design-space is often loading or fixing area, So the same material would get better result, Is it right? 2、Calculix can solve nonlinear contacting model. If some contacting elements are removed or added back, The vonmises values of those elements maybe not exact. So topo optimazition is better match for linear analysis type. Is it right?

fandaL commented 5 years ago

1) You can use any material for the domain. There was same material in non-design domain as in design domain because parts are from one material by engineering design. Non-design domain was used around bolt holes because bolts were modelled only as fixed surfaces or rigid body elements, which does not fit reality around bolt exaclty, so the space is prescribed as non-design. 2) I have not tried it on examples but, theoretically, program should work with nonlinear models as well. But I would keep a model linear wherever it can roughly catch reality for two reasons. First, nonlinear task takes much longer to calculate so that in case of topology optimization where you need many elements to catch whole design domain you would feel it a lot. Second, I would be afraid of convergence especially when elements can be removed from the contacting surface or externally loaded elements. Mesh could quickly distort on "void" elements and contacts could have problems to converge as well.

461353349 commented 5 years ago

I see. Thanks very much for your guidance!