Thread: Bracket theory
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  #49  
Old 04-04-2013, 09:26 PM
martin martin is offline
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Join Date: Jan 2007
Location: panama City Fl.
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Quote:
Originally Posted by FishStretcher View Post
I did some stress analysis on a 24" bracket with (importantly) a center rib in the flotation volume.

The center rib helps a lot.

The loading is for 5 Gs. (not 10) Plus full thrust from a 100 hp outboard. Something sort of like the loading you might see landing after skipping off the top of a wave.

The deformed shape is magnified 50 fold so you can see what happens.

A rib that goes from the real transom to about halfway between the lower two outboard mounting holes seems to be an important structural feature.

Yield strength for this aluminum is ~180 MPa, but repeated stresses above 50 MPa would be a bad thing, in very general terms. I expect the loading from the outboard holes to be much lower, as the stress is distributed along the casting, not just inside the bolt holes.
FishStretcher
What are the psi stress point on you annalsist.. I have twin out boards on a bracket and need to know what stress he bracket can take.. 30 inch set back.. ..1/2 inch back plate 1/4 " platform and side and bottom.. 1/2 inch 3 " inch angle .. 6061t .. You can see bracket on my other post 76 23 seacraft thanks Martin
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