Virtual Paper

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Permalink Reply by Gregory Epps on February 9, 2010 at 0:25

Hi Daniel - the main one I guess would be Denis Sheldon's PhD from MIT while he was at Gehry before he became CTO...

http://dspace.mit.edu/handle/1721.1/16899?show=full

I'll try and think of some others...

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Permalink Reply by Daniel Piker on February 10, 2010 at 8:32

Thanks, that seems great, I'll look into it.

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Permalink Reply by Gregory Epps on February 9, 2010 at 0:28

Helmut Pottman has also included some energy calculations in his work on single curved/developable surfaces - so could give some pointers. His paper curved folding has referenced other papers which deal with this too, so worth digging those out...

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Permalink Reply by Gregory Epps on March 29, 2010 at 11:08

Dan Piker has set up a Google Group for his Kangeroo Physics engine for Grasshopper... check it out.

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Permalink Reply by Daniel Piker on March 29, 2010 at 11:32

Thanks Gregory!
and nice work at SG - wish I'd been there.

Also - maybe this has already been linked, but Lorenz Lachauer has been posting some really interesting developable surface stuff recently over at eat-a-bug.blogspot.com

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Permalink Reply by Irene Scudellari on July 13, 2010 at 10:57

Hi Daniel,
can kangaroo simulate the behaviour of folded metal?

Irene

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Permalink Reply by Daniel Piker on July 13, 2010 at 15:29

Hi Irene,

Yes, the simulation of 'paper' I have been working on could also be applied to other sheet materials that strongly resist shear and stretch but bend out of plane relatively easily - such as metal.

Of course typical sheet metal has much higher bending stiffness, which would matter if you want to use particular values for the loads. I have been working on stability at higher stiffness values and making progress - a new version to be released shortly.

Also, when it comes to the actual folds I guess there is some plastic behaviour to consider if you wanted to get really into detail.
Any digital simulation is a vast simplification of real world behaviour, I think the best thing will be to try some experiments simulating curved folding of sheet metal in kangaroo and see how closely it corresponds to reality.

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Permalink Reply by Shawn Fernandez on July 13, 2010 at 19:50

I think for what she's doing the "bend deduction" caused by plastic deformation would likely be small enough to go unnoticed, especially with the slots cut into the material, they will relieve the internal stresses considerably.

I have thought about both of these of these directions (curved folding and accurate sheet metal bending) often over the years wishing there was software out there that actually simulated them. The thought of them both coming together at the same time would be amazing. Unfortunately accurate simulation would require (among many other things) knowing the method of manufacture and tool geometries.

A big leap towards accuracy could be attained though by taking a curve input for the stress/strain curve of a particular material. Most sheet metal bending in industry throws all of the physics (unknown factors) into a K-factor as a percentage of material thickness. For the time being, perhaps you could take a similar approach.

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Permalink Reply by Daniel Piker on July 13, 2010 at 22:51

Thanks Shawn -
Yes, I agree that the option to input stress/strain curves would be quite useful.
It would also be nice for other things like Lennard-Jones potential, and I think not too complex to implement.

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Permalink Reply by Irene Scudellari on July 15, 2010 at 10:56

Thanks Daniel,

I would like to try it but I cannot use the latest release because I haven't got the latest Rhino service release.

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