Please quantify added strength 2

[M249Gunner]

Hi all,

I have a standard PJP groove weld joint configuration where 2 members are to be joined (members B and C) ; but then a somewhat non standard reinforcing fillet weld over it that joins members A, B, and C togather.
I am looking for assistance as to how to present quantifiable evidence as to how much strength the reinforcing fillet weld adds to the PJP groove weld.I assume the effective throat for the groove weld becomes 1.75mm if welded as shown in "Option 2"?? What calculation would I use to show the additional shear and tension strength values for "option 2"? Please see attached sketch of both options.

http://files.engineering.com/getfil...s_PJP_groove_w__Reinforcing_fillet_sketch.doc

Any help you could provide would be greatly appreciated. Thanks!

 

[connectegr]

I don't see how any reinforcement is given to the PJP weld in Option 2. For additional strength the fillet weld should exceed the profile of the PJP.

http://www.FerrellEngineering.com

 

[M249Gunner]

Thank you for the response. I'm not sure I understand your comment about the fillet not adding to the PJP profile. It is situated directly over the PJP groove. Would that not effectivly increase the PJP groove weld throat? If not, could you explain why?
Thanks again.

 

[Duwe6]

Yes, your massive fillet cover will increase the effective size of your Partial-Penn weld. Strength/throat should be measured perpindicular(sp) to the beveled piece, so the increase in strength is slight compaired to the welding time.

Why not bevel the horiz. member more, to increase the Depth-of-Prep? This will reduce the welding time and more than pay for the extra beveling time.

 

[gtaw]

AWS D1.1 may not apply, but it is a good code to use if a different standard is not already impossed.

I suggest the load be transferred from one member to the next, i.e., the weld between C and B should be independent of the weld between A and B.

The rational is that you do not want to size the welds such that the base metal fails. Ideally the weld and base metal stresses would be balanced.

The allowable stress on the PJP and the fillet welds is limited to 0.3 x the tensile strength of the filler metal. The area of the weld is 0.707 x the (shorter)leg x the length. The allowable stress on the base metal cannot exceed 0.4 x the yield strength of the base metal or 0.6 x the tensile strength of the base metal.

Best regards - Al

 

[gtaw]

Your shortest failure path will determine the strength of the weld.

Draw the shortest line from the root of the PJP with reinforcing fillet and compare it with the shortest line drawn from the root of the fillet weld (joining A to B). The shortest failure path will govern.

Next compare the strength of the filler metal to that of the allowable stresses on the base metal. You cannot increase the strength of the weld to increase the strength of the joint without considering the allowable stresses on the base metal. This essentially prevents the designer from using a 100ksi filler metal on 36 ksi (YS) base metal. The lower allowable stress of the BM would take precedence over the strength of the weld.


Best regards - Al

 

[Duwe6]

Appropo of nothing above, I prefer an M-240Bravo

 

[M249Gunner]

Thanks guys! I appreciate your comments and answers. I know that the joint is a little unorthadox but I have a situation where I'm told :"it's always been welded that way" and I'm asked to justify it to the customer. Your responses will at least allow me to offer some credible argument.
Thanks again.
BTW....M-240B is an awesome toy as well. A little heavy to hump but nice to have when needed.