HAZ reducing shear capacity. 3

[wadavis]

I'm reviewing the design of a stout aluminum box beam that has a history of shear failure in the HAZ at the web to flange connection. This is an exercise in optimization, we wish to change the welded detail to increase the shear capacity without overhauling the rest of the beam.

How do you, as the designer, reduce the degradation of the HAZ?

I'm looking at a full penetration bevel with a backer (only access from one side), this increases the bonded surface from the old detail, but adds four times the filler metal. Does that much more filler metal, and therefore heat, have a strong effect on the HAZ?

wadavis
E.I.T.

 

[3DDave]

I was thinking along the lines of tapering the top and bottom flanges and the webs from the inside so the outer profile was constant, but material excess to strength could be removed - like butted tubing.

Alternative uses would be producing a sinuous web to prevent buckling or a constant wall thickness but a tapered tube.

I also wonder if a rotating embosser could add pre-formed gear teeth as the material is extruded, even if they were only a good approximation there's some value.