
Algorithms that design structures better than engineers - jordn
http://jordanburgess.com/post/41386795824/topology-optimisation
======
Loic
The title is totally misleading, what he is showing is exactly the work of
engineers, that is, defining a set of targets and constraints for a problem
and using the right tool to find the best solution. In fact, you have
engineers involved at each step in the provided solution, to define the
problem, to select the right algorithm, to run the simulation/optimisation and
to critically assess the quality of the answer.

~~~
stiff
Agreed. Unfortunately it seems to be a common misunderstanding of optimization
and things like machine learning, that you somehow have this set of almost
universal black boxes that can apply to any domain without much thought. When
you gain some practical experience it becomes clear that good results come
from knowing the domain very well.

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bencollier49
One of my lecturers (many years ago) did some interesting work synthesising
circuits like band-pass filters using genetic algorithms:

<http://www.personal.rdg.ac.uk/~stsgrimb/netsyn.htm>

The algorithms came up with some very unusual circuit designs which did the
job better than classical solutions, in some cases.

~~~
crististm
That looks very good as a starting point.

Im the demo page I was looking for the BOM and the parts values. Being non-
standard this implies limitted applicability in practice.

Did you consider adding constraints to part values?

~~~
bencollier49
You'd have to ask the chap who did it! This wasn't mentioned though. I think
the code is available in the papers concerned; it would be relatively trivial
to add "rounding to nearest available part" to the assessment criteria, I
imagine.

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TelmoMenezes
A friend of mine did something similar with evolutionary algorithms:
<http://kowaliw.ca/projects/deva.html>

~~~
mblake
This is very interesting, thank you for sharing.

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gmt2027
The Genetic Programming community offers annual awards for 'human competitive'
solutions in different domains that match or exceed the designs of human
experts. A number of these automatically generated solutions rival recently
patented technologies.

<http://www.genetic-programming.org/combined.html>

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NamTaf
Part of the trouble with this is that often, design isn't about the 'optimal'
in a single degree of freedom but rather a case of balancing a larger number
of design criteria. Having said that, the technology does hold a lot of
promise and I already use very rudimentary similar tech (eg: iterative FEA to
converge on minimal plate thicknesses for a structure under given static load
cases).

I agree that 3d printing will help liberate designs from some of the
constraints (namely, some of the fabrication constraints - they're some of the
most difficult to incorporate in to an 'optimal' design) but I still think
there will remain a number of considerations that design engineers must make
that will involve sacrificing ideal structure for other advantages:

\- Interfaces with other equipment / interoperability in a system: curved
surfaces aren't too good at being bolted together. A spider-web mesh of
structure forming a super-rigid but super-light chassis doesn't lend itself to
fitting an engine inside. A design might need 30 years' service out of one
part but maybe another part (eg: a hopper for corrosive mineral concentrate)
only wants to withstand 3-5 years - it'd need to be easily separable from the
parent structure so that can happen.

\- Maintainability: holes in the parts where 3 beams of the truss converge are
just asking for moisture ingress leading to corrosion. Some surfaces may not
be easily painted because they're tucked away. Some areas need to be
accessable to hand-sized objects in order to perform non-destructive testing
for internal cracks/defects.

\- Portability: it's all well and good to have a single, continuous structure
until you have to transport it by truck to site hundreds of kilometres away
and down a mine shaft to its intended location. A less optimal but heavier
design may in fact offer a better whole-of-life cost if it can be fabricated
in China and flat-pack shipped to where you need it, reducing the up-front
cost compared to a more elegant, more optimised but more expensive to
construct design that is then difficult to ship to site.

This is a topic that fascinates me. I really look forward to seeing what comes
out in the next 10 years. Even in the last 5 years, I've gone from solving a
60000-element finite element model in 15 minutes, to solving an 80000-element
model in 30 seconds. This is about the minimum size I need to do basic
analysis on a complete structure, eg: a coal wagon. That smaller timeframe
makes iteration so much more possible. I'll be able to now perform more than
just iterative convergance on plate thicknessses - adapting the geometry of
the model and remeshing is now within the realms of possibility. Similarly,
pre- and post-processing software is becoming more capable of interpreting
results and intelligently adapting the model to suit.

My biggest fear of this technology is that, like FEA makes possible already,
many Engineers will fall to the trap of 'garbage in, garbage out'. It's very
easy to construct a model that looks like it should represent reality and
solves mathematically just fine, but doesn't give realistic or meaningful
results. This technology looks like it could amplify that problem
significantly. Presently, the only way you learn the unwritten rules of
computational analysis is through tutorage by more experienced colleagues. A
design that's far more complex because of more complex algorithms will be
subsequently far more difficult for them to advise and correct on. Sometimes
that simplicity of an inelegant and un-complex but well-understood structure
is preferable.

~~~
JoeAltmaier
It has it uses. Interior of molded plastic structures e.g. cases for
appliances etc. Where the variables used are important - material
used,strength - and painting and transporting are not an issue.

~~~
NamTaf
Definitely agree. Moulded plastic would be one of the better ones. Castings
would be ok in some circumstances though the interior cores could be a pain to
control, eg: ensuring the sand to create the voids is solid enough not to
disentigrate as you try to cast and is not just floating in mid-air.

~~~
JoeAltmaier
Right - or 3D printing as the OP suggested.

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robomartin
This is neat stuff. It's the future and, yes, in some fields it is now.

I've applied GA/GP techniques in a number of areas. There are still a number
of issues when applying this method to mechanical design.

A naive implementation can produce structures that are either impossible to
fabricate or insanely complex and expensive.

It is easy to also optimize away safety factors. The pictured truss might be
optimal under ideal conditions yet fail in spectacular ways if even a small
crack or a bad weld develops somewhere. Remember, rust never sleeps. There's
also the case of material quality and consistency (is all aluminum equal?).

One application that was a lot of fun to work on was the evolution of an
optimal cooling solution for a very high power (1500W) LED array. I evolved
the solution using what I am going to dare and call a manual-GA approach.

All of the mechanical modeling was done using SolidWorks and
FlowWorks/SolidFlow FEA package. The mechanical model was designed to be
parametrically controlled from extensive geometry tables that could be edited
with MS Excel (which made it so much simpler). The approach was to run
reasonably realistic (meaning, close to what you could actually fabricate)
structures. Each structure took 16 to 18 hours to run. Using multiple cores
and machines we could get a set of them done overnight for evaluation the
following morning.

The evaluation function consisted of agreed-upon parameters that came out of
the FEA simulation: delta T, max and min temperatures, thermal uniformity,
etc. These were used to calculate a score for each structure.

Once enough data (enough variants or "chromosomes" if you will) accumulated,
the manual "natural selection", "reproduction" and "random mutation" steps
would take place.

Over a period of about eight months this work produces some really
interesting, unexpected and, I think, innovative approaches to the problem.

I learned a lot by taking this approach. I also learned just how hard it would
be to fully automate such a project. I am not necessarily speaking about the
tools involved as much as the need to encode manufacturing knowledge into a
system such that it autom-magically evolve objects one can actually construct.

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cpg
Something similar is being done for buildings by a startup called Aditazz
<http://www.aditazz.com>

Very interesting. It's like designing chips, but for buildings. On the cloud!
They are starting with a vertical that it's like CPU's ... hospitals! It's the
kind of thing you wonder why we (as the human race) did not get to play with
this until now, given that we have been building structures for so long!

[Disclaimer: I helped build early prototyped of their cloud infrastructure for
them and know the founders]

~~~
huherto
Pretty cool.

Do you or anyone knows if there is something like that for distribution
warehouses?

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mblake
Not exactly related to the post's contents, but I'm so excited I found out how
this sort of this is called: topology optimization. I've been thinking about
designing an 'object' under certain constraints and I didn't know exactly
where to start.

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murbard2
The topology optimization space at the Ecole Polytechnique has some nice
resources on this <http://www.cmap.polytechnique.fr/~optopo/index.php>

~~~
jordn
That looks really helpful, thanks!

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MichailP
This looks really nice. Do you think similar algorithms could be used in
electromagnetics, for example automatic design of antennas?

~~~
jordn
Plenty of examples of just that, here's one:
<http://alglobus.net/NASAwork/papers/Space2006Antenna.pdf>

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jlarocco
Not much information content there. I'm not sure what the point is. Some guy's
blog saying, "Hey, this exists?"

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dj-wonk
And who designs the algorithms? ;)

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liuh
Saw this ten years again. Still use the exactly same optimized structure
example.

