Torsion box design in depth info?

[Oldmanandhistoy]

Hi all,

I’ve just spent almost an hour tiring to find in depth information on torsion box design and not got very far. I’m hopping some one has the time to post links to good information.

I have built many things using torsion boxes and have to admit they have been designed using just my common sense. I would like to be able to design using some established principles such as rib, skin thicknesses and rib spacing.

So any useful links would be very much appreciated

John

[ger21]

http://www.diynetwork.com/diy/shows_..._26946,00.html

http://thewoodwhisperer.com/episode-...e-torsion-box/

Not sure how much info those links have. I bought a magazine a few months ago with an article on torsion boxes, but it didn't really have any technical info. Woodworkers Journal June 2007. It mentioned that rib spacing should decrease as skin thickness decreases. Rib thickness didn't make a lot of differrence, but strength was related to the glue surface area between the ribs and skins. Which would mean the thicker the ribs, the stronger the box. But I don't think you need to go with anything wider than 1/2" for the ribs.

[Oldmanandhistoy]

Originally Posted by ger21 http://www.diynetwork.com/diy/shows_..._26946,00.html http://thewoodwhisperer.com/episode-...e-torsion-box/ Not sure how much info those links have.

Thanks very much for the links, I’ll take a look

[martinw]

Dear Oldmanandhistoy,

Try searching "stressed skin panel". A "torsion box" is a stressed skin panel in two directions. Structural calculations for stressed skin panels are well explained in "Timber Designers Manual" by Ozelton(?) and Baird. It is BTW, the most fantastic book.

Best wishes,

Martin

[Oldmanandhistoy]

Originally Posted by martinw Dear Oldmanandhistoy, Try searching "stressed skin panel". A "torsion box" is a stressed skin panel in two directions. Structural calculations for stressed skin panels are well explained in "Timber Designers Manual" by Ozelton(?) and Baird. It is BTW, the most fantastic book. Best wishes, Martin

Thanks Martin,

Your recommended search gave me this on the first page, which at first glance looks very promising.

http://gp.com/BUILD/DocumentViewer.a...elementid=3815

Regards,
John

Btw please just call me John

[martinw]

Dear John,

There is a PM for you. Borrow my copy of Timber Designers Manual if you want.

Best wishes,

Martin

[Oldmanandhistoy]

Originally Posted by martinw Dear John, There is a PM for you. Borrow my copy of Timber Designers Manual if you want. Best wishes, Martin

Thank you