test fatigue welding joint roller

[Ing.Vedder]

Good evening,
I have a two-sided roller created with a thick mechanical tube which at the ends welded two studs made with a full round bar on which the bearing supports skf are mounted.
I need to evaluate the fatigue resistance of the circumferential welding that joins the cog to the thick strong tube as from detail below.
I tried to look at both part 9 ec3 and the old uni7670 on the lifting devices (two norms that I always use as a reference for fatigue calculations) but I did not find a case similar to mine, the only thing is the particular 12 of the 8.5 outlook of the ec3 but does not convince me completely.
Would someone know how to indicate a manual verification path (at this stage no fem) for an angle welding of that type?

p.
the cod is welded to the pipe but being then a full round will also be planted in the pipe in interference, therefore it is lawful to think that the soldering will work "less" of what can be thought. However I would like to find a method of calculation as if I had to rely 100% on the soldering in question


Thank you all! !

 

[Ing.Vedder]

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[Ing.Vedder]

 

[meccanicamg]

if the tube is inserted with interference, as we normally do, it is he who has to keep torsion. compression/cut on the graft. welding is of beauty and is made to improve the joint capacity. if it cliques means that interference is nonexistent.
As described in the Eurocidice 3 uni en iso 1993-1-8, the welding cord must be checked statically, imposing in your case that it is only he to carry the load. to do this are described two methods: simplified method and method of overturned tensions (absolute to the old cnr uni 10011 now withdrawn from twenty years).
for fatigue analysis there is the sigma/number cycle method with the miner method as uto in Annex 5.
Moreover to complete the thing, for the various formulas you must also use uni en iso 1993-1-9.

to do fem analysis, it is not enough to do it statically but it is necessary to use a fine mesh and to use the methyl hot spot stress on three points and it is a procedure however not very easy.

In fact even the calculation normally requires a little time, effort, reckoning and putting it definitely in excel and speeding things up.

 

[Ing.Vedder]

the tang is planted in interference in the tube, but what worries me is not the torsion of the motor (it is a motorized roller), but the flexional and cutting loads deriving from the load that passes on it (variate tons, with frequency of thousands of cycles die).
Despite this, however, I would like to try to dimensional as if everything (flavor, cut and twist) went through the corner cord.

the static verification of the cord does not bother me, I take throat height, rebound and I find the various sigma that then combine, okay.
I'm worried because I don't find a methodology to use, on the 1993-1-9 uni en iso (norms designed more for carpentry than for a mechanical roller) I don't think that any detail of fatigue between those presented is my case.
Finally, you mention Annex 5 but I am sorry I did not understand what norm.

hot spots are a way but as you said it is long and complex therefore I would keep it as the last beach and definitely not at this stage of the project.


Thanks a thousand mechanicsmg for the help!

 

[biz]

try to take inspiration from qui

 

[pollo]

In the past, I had an accident in a similar situation: being beauty welding, it had as a practical effect that to hide the situation below, until the clique in the base metal did not propagate beyond the limit and welding, of course, has torn.

 

[Ing.Vedder]

try to take inspiration from qui

thanks for the link, it seems interesting.

reading what I understand is precisely the fact that for calculations "hand" you have to know from literature the s-n curve associated with your fatigue detail to find the tensions in play and to make reasoning on fatigue life. .
and that's where the problem comes to me: I don't have a s-n curve to do it again, and here I cry!

 

[Ing.Vedder]

In the past, I had an accident in a similar situation: being beauty welding, it had as a practical effect that to hide the situation below, until the clique in the base metal did not propagate beyond the limit and welding, of course, has torn.

I would use here the old uni7670 for the verification of the base metal that I imagine will be planted inside the tube up to a shoulder with consequent connection raggetto.

 

[pollo]

Unfortunately it was that too ino connection raggett, so much so that between zta and concentrations to the edge, started the clique with the result of the photo (it was a pull of movement a pantograph crane). the element was also checked periodically, but under welding inspection had no effectiveness