I started to work with stress constraints. It's pretty interesting and up to now more stuff seems unclear to me that being clarified.
I read a bunch of papers, but need to read the original Duysinx and Bendsoe; Topology optimization of continuum structures with local stress constraints; 1998 paper again (maybe there are the answers to my questions hidden :)). Our results are in good agreement with the standard solutions, so our approach seems to work. However, the results of Le; Stress-based topology optimization for continua; 2010 are really extraordinary good, unmatched by any other publication I read and far better that our results.
I still wonder, why
min vol
s.th. stress constraint
works. At least for qp-regularization (Bruggi; On an alternative approach to stress constraints relaxation in topology optimization; 2008) rho_min should be the global optimum. But the results are all similar to the compliance solution. I cannot imagine, that the regularization just hides this global optimum as we use a second order optimizer ... well, I hope I'll find out.
The next thing is, that beside Le, all (of what I read up to now) published results show some grayness embedded in full material. What happens if we have to map to manufacturable black and white topologies? I have not found any discussion of this grayness yet.
