Stress concentration

[Verkstad]

Hi,

I have a case here where i would like to know what the stress concentration factor conservatively (see below). I have heard that if you set 3 then you are safe?

 

[MJCronin]

Yes, I have heard that too ....

MJCronin
Sr. Process Engineer

 

[EdStainless]

It depends on the loading.
If this is fatigue it would be worse than that.
But for low cycle and static loads 3 is usually in the right range.

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P.E. Metallurgy, consulting work welcomed

 

[Verkstad]

Thx for the replies. What would considered to be low cycles in this case?

 

[rb1957]

what does welding do the material properties ?

we're assuming zero voids, even little tiny ones ?

"surely" someone has done some research on the fatigue of welds ??

another day in paradise, or is paradise one day closer ?

 

[EdStainless]

Yes it depends on a lot of factors.
You have to make a bunch of assumptions; ductile materials, properties largely unchanged by welding, weld filler modestly stronger than base metal, loads a small fraction of ultimate, no high cycle fatigue, and so on.
Of course a lot of this goes away if they just use a full pen weld

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P.E. Metallurgy, consulting work welcomed

 

[NRP99]

Slightly different perspective. IMO the weld, in practical, is full pen weld since root of 1mm will get melt. Then the stress concentration will not be of big concern since the weld is/going to become full pen.

 

[Verkstad]

Just for the diskussion asume it is not fully pen.

Lets say 14k cycles what would a conservative factor of stress concentration be?

 

[Tmoose]

https://app.aws.org/technical/d3/D1.1_2000_Section2_Design.pdf