I want some help with advice how to design a joint that was originally welded. The designers have added a pin to support the weld between a tube and a shaft. I have been reading Two articles : "Mixing Welds and Bolts" part 1 and 2 from Welding Innovation and "Strength of joints that Combine Bolts and Welds" (Kulak and Grondin), written in 2001-2003. After reading I still don't think it is clear if the pin will add any strength to the construction. The tube and shaft is part of a roller and therefor will is the weld cyclic loaded.
Hi Susanne,
Welcome to the AWS Welding Forum!
Was the pin press fitted or have no wiggle room? If so, the load is acting on the both the pin and weld simultaneously.
You could come at it another way and assume the weld is taking the full load. Then design the joint accordingly, and the pin would become a safety factor.
Tyrone
Thanks for the reply.
The pin was press fitted. The product is like a roller and the weld/pin keep the hollow tube and shaft connected. The the roll rolls the load becomes cyclic.
Hello Susanne, in my experiences, a bolt will often be provided for assembly and line-up of certain structural members and essentially only serve to hold things in place so that welding can be accomplished. The bolt is "not a factor" in the strength or design of the joint. My $.02 for what it's worth. Best regards, Allan
Susanne,
WELCOME TO THE AWS WELDING FORUM!!
I take it this is not actually a 'Structural' application? As in a building?
Either way, is the shaft inside the tube and then welded around the end of the tube to the OD of the shaft? I assume so since you are able to add a pin that according to the theory of some will add strength to the application.
If because of your cyclic application this has been determined to help keep from snapping the weld and allowing one part to spin while the other remains still, it will more than likely help. I take it one part is connected to a drive system and the other is somehow moving something else? Does it change direction and do so in regular cycles? Back and forth?
Depending upon how far the shaft is inside the tube it may even help to add more than one pin. This is not exactly the same type of application as the articles you are referencing. Structural application as Allan and others have leaned toward is not the same as the cyclic action of a power driven shaft. There may be parts that would still overlap but the function is different.
Have a Great Day, Brent
Thanks for the reply.
The product is like a roller with the shaft inside a hollow bar. The weld and the pin keep the together.
You can read the Commentary in AWS D1.1:2010 for additional insight.
Generally it is not a good idea to share a load between bolts and welds in a common plane/faying surface. Bolts, even in a slip critical connection, will slip into bearing when fully loaded. Until the bolt is in bearing, the weld carries a disproportionate load.
The AISC rules have recently change in response to the research of Kulak and Grondin.
Best regards - Al
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