iTop - interactive topology optimization

Our work group developed an interactive topology optimization web client.

eamc080.eam.uni-erlangen.de/iTop

This is very similar to topopt from Ole Sigmund's group. While topopt demonstrates the possibilities of topology optimization (including mechanism design and 3D compliance), we somehow have a more educational focus.

With out interactive topology optimization (iTop) you can play with the regularization and optimizer. Furthermore we include 2D material design where e.g. auxetic material (negative Poisson's ratio) can be designed.

A good example is SNOPT as optimizer with slope constraints as regularization. Both are rather slow for compliance problems but for very challenging material design problems this might be the only possible choice.

What I often show is the non-convex property of penalized compliance. Enable "start optimization from current design" and "restart new optimization on parameter change".
For sufficient penalization, moving the force point might result in a clearly poor local solution. Now taking away the penalization (switch to 1) and activate it again (e.g. 3) the "global optimal" solution is found.

For several parameter sets optimization might fail. By this we want to demonstrate, that optimization is not a black-box problem!

The documentation and all the references are still missing, therefore we do not link to iTop officially from our chair's web page. We hope we can provide some documentation soon.

While being based on our optimization software, iTop is a demonstrator tool only. This is not necessarily the kind of problems we solve in our academic work. iTop contains just a small selection of our tools.

Enjoy and ask if you have any questions.

eamc080.eam.uni-erlangen.de/iTop

Self-Penalization in Topology Optimization

I gave a talk at EUROMECH 522 in Erlangen on the 10th of October 2011.

It appears that most people from the audience did not understand what I wanted to say - so clearly a bad presentation of mine! :(

However, discussions during the conference after the presentation helped me point out the missing items and emphasis in my presentation.

Therefore I provide here a variant of the talk with some additional slides. If you are interested in the subject I'll be very happy to discuss it with you! :)

The key point is, that I do not present anything like a method or something big. I just want to motivate to have a slightly different point of view on our daily topology optimization problems. (But to be honest, to my humble personal opinion this off the mainstream look on topology optimization might result in important insights :))

Self-Penalization in Topology Optimization

View more presentations from fwein

Thesis Submitted

I finally submitted my thesis! :) I guess the defense will be in September or October. Afterwards I will publish my thesis online for free download. The title is "Topology Optimization of Smart Piezoelectric Transducers"

It basically consists of three parts:

* Topology optimization of piezoelectric actors, with single-frequency loudspeakers in mind.
* Topology optimization of piezoelectric cantilever type energy harvesters
* Self-penalization in topology optimization

For the harvester I applied piezoelectric dynamic stress constraints, which were actually easier to handle than in elasticity as I do right now :)

The self-penalization stuff goes much further than covered in the piezoelectric self-penalization paper.

The introductory stuff became quite extensive. When the thesis is published my plan is to compile all the linear elasticity stuff to an "Introduction to ersatz material topology optimization in linear elasticity", which might serve as what the title suggests. :) The idea is to publish it as technical report and provide free access to it.

I'm happy that writing the thesis is over! My plans for the future are not settled but it looks like that I stay for some more time in academia. ;)

EUROMECH522 and Piezo-Workshop 2011

I'll be at the 7th International Workshop on Direct and Inverse Problems in Piezoelectricit, October 4th - 7th, in Oer-Erkenschwick, Germany. It is a very small town but Moondog lived there for some years. I was at the 5th and 6th Piezo Workshop. It is a small event in a very comfortable atmosphere with very easy exchange to other people. I learned a lot about piezoelectric material there.

Following is the EUROMECH522 "Recent Trends in Optimisation for Computational Solid Mechanics" October 10th-13th in Erlangen. It is an colloquium with invited participants only (as far as I understand). I hope they accept my abstract. I want to talk about self-penalization in topology optimization. I have some new results/observations in addition to the paper On the effect of self-penalization of piezoelectric composites in topology optimization. The dynamic stuff is still an open issue and I have not explored some ideas I had. In case I'll get accepted to EUROMECH522, I'm quite curious about it as I haven not been on such an colloquium before. I hope many Danish topology optimizers come, they are the reference.

For private reasons I won't come to WCSMO-9 :( That is sad as WCSMO-8 was the most important conference for me up to now.