Sunday, June 28, 2009

Re: crimping of aluminum

Conrad and James,
Thanks for your input.
According to my client (a reputable manufacturer), they have been using this connection for years, tested it, and found its strength an equivalent of a corresponding fillet weld all around the connecting parts.  Apparently, they even tested the connection for fatigue and the results were quite satisfactory.  I haven't seen any documentation on the testing yet; the photos look pretty neat, but depict something very remote from the structural connections I am accustomed to and ready to approve/accept right away.
I do not really want to get any deeper into the domain of mechanical engineering.   I am planning to contact the North American aluminum guru tomorrow and find out if such connection in this particular application is acceptable to the aluminum industry.  If it is, I will pursue the testing docs avenue; if not - I will have to recommend some other connection.
V. Steve Gordin, SE
Irvine CA
----- Original Message -----
Sent: Sunday, June 28, 2009 19:46
Subject: RE: crimping of aluminum




Crimping, and tags & slots are common in residential steel framing. As far as I know they are assessed by testing.


They are just one form of mechanical fastening common in plastics and suitable metals. The crimping connections are basically an interference press fit, forming a shear lug. I wouldn't rely on the interference fit to resist force, but the lug in shear is similar to a rivet. I'm assuming the crimping involves forming a plug on one member and a socket on the other and then forcing them together all in one operation: or group of such plugs and sockets. Not just crushing one member tightly around the other.


Books on mechanical or integral fastening methods should provide design guidance. I vaguely recollect that one of the handbooks by the Society of Manufacturing Engineers (SME (US)) covers joining/assembly and includes some guidance: if you have access to a suitable library.




Conrad Harrison

B.Tech (mfg & mech), MIIE, gradTIEAust


South Australia