Just trying to figure out how to strengthen these corners.  With the loads they will be seeing, they are yielding.  I don't believe they will after they are welded together, but I can't seem to get a "real" weld into these corners to test.  I would settle for a smooth fillet just to spread the load out over a little more area.  Or I can gusset the corners I guess.  Any ideas?


Categories: Modeling and Assemblies, Weldments

Comments
Last comment By: Igor Fomenko   Wed, 21 Feb 2018 16:56:46 GMT
Re: Strengthening Corners of Welded Pipes

Hi Russ,

 

If this was part of a spreader beam frame or a lift frame I would see if I could position the lug in the corner and size it to extend inwards.

Plate is cheaper than man power and fit-up. No cope. Less heat induced stress riser. That simplifies & minimizes all your structural welds plus increase the lug capacity since it is not tied to the butt joint on the round tube wall connection.

Then you have the option to straight cut your diagonal. You can weld the diagonal by slotting it or cut out a notch in the plate itself.

I can't see the rest of the design, but in case of a lifting frame it would simplify the design and structural stress calculation. As i said if this is a lifting frame.

 

By: Elmar Klammer  Wed, 21 Feb 2018 12:09:27 GMT
Re: Strengthening Corners of Welded Pipes

I don't do weldments pretty much at all but can you add a gusset member to the top and bottom of the intersections and weld it all together?

 

 

Steve C

By: Steve Calvert  Wed, 21 Feb 2018 12:23:20 GMT
Re: Strengthening Corners of Welded Pipes

Those are both good ideas. This is a lifting fixture. The smaller diameter pipe angled inwards has a load in the center of this square structure. So the yield is happening where the small pipe joins the larger pipes in the corner. Maybe a gusset similar to Steve’s idea will spread the load. However, it may concentrate the load  on the edge of the gusset that crosses  the small pipe. Maybe smaller gussets on either side of the small load?

By: Russ Karnap  Wed, 21 Feb 2018 13:34:08 GMT
Re: Strengthening Corners of Welded Pipes

Yes, the idea was to have one on each side but I didn't show that.

 

Steve C

By: Steve Calvert  Wed, 21 Feb 2018 13:41:31 GMT
Re: Strengthening Corners of Welded Pipes

I'll try this now.  Moved the lug parallel to the pipe and directly above the corner load to save time trimming the steel as Elmar Klammer mentioned. I'll let you guys know how it goes:

 

Screenshot 2018-02-21 09.15.11.png

 

Thanks,

Russ

By: Russ Karnap  Wed, 21 Feb 2018 14:18:20 GMT
Re: Strengthening Corners of Welded Pipes

Hi Russ,

 

Your original lug was rotated before. Not sure how your rigging looks like. On a single point rigging setup you will get out of plane bending in the lug and unfavorable shackle loading.

 

Elmar

By: Elmar Klammer  Wed, 21 Feb 2018 16:09:54 GMT
Re: Strengthening Corners of Welded Pipes

Design sketch 1 (top)

Design sketch 2 (hinge). Angle is according to your design intent.

Model without bending stresses and curved surfaces (Part is attached)

By: Igor Fomenko  Wed, 21 Feb 2018 16:56:46 GMT
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