welding of dynamically loaded structures
welding of dynamically loaded structures
(OP)
does anyone know the allowable undercut ( if any) in a dynamically loaded structure?
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welding of dynamically loaded structures
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welding of dynamically loaded structureswelding of dynamically loaded structures(OP)
does anyone know the allowable undercut ( if any) in a dynamically loaded structure?
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RE: welding of dynamically loaded structures
RE: welding of dynamically loaded structures
RE: welding of dynamically loaded structures
You do not state what code you are working to ?
Both AWS D1.1 and AWS D1.5 allow undercut but the acceptance criteria is based on specific variables - AWS D1.1 Table 6.1 (7) and AWS D1.5 Clause 6.26
Hope that helps,
Regards,
Kiwi
RE: welding of dynamically loaded structures
An undercut greater than 1/32" used to be a weld defect according to AWS D1.1, look in the ‘Qualifications’ chapter for undercuts. Depending on the orientation of the undercut w.r.t. the loads and stresses, they can be a significant discontinuity or stress raiser on the surface of the parent metal, all the more so in a structure which is dynamically loaded. Start and stop craters fall in the same category of defects and can be hot spots/hard spots too. You probably won’t find a citation which says ‘Madax shalt not allow undercuts which run in this or that direction,’ you must use some engineering judgement in these matters. But, they are a standard visually inspected defect if to deep. Many welds have some very minor undercut.
RE: welding of dynamically loaded structures
RE: welding of dynamically loaded structures
Best regards - Al
RE: welding of dynamically loaded structures
RE: welding of dynamically loaded structures
Dynamically loaded structure - B31.3 ?
Regards,
Kiwi
RE: welding of dynamically loaded structures
D1.1 does not mention Dynamically loaded structures in table 6.1, how is applied in B31.1?
RE: welding of dynamically loaded structures
RE: welding of dynamically loaded structures
RE: welding of dynamically loaded structures
There may be Euro ISO specs with different criteria, but D1.1 & D1.5 have a longer history and they work. Reinventing the wheel is usually a futile excercise. If you want to write a spec different to a historically accurate & workable one, you better have a lot of research and testing data to back it up.
RE: welding of dynamically loaded structures
Best regards - Al
RE: welding of dynamically loaded structures
The OP stated a "dynamically loaded structure".
What exactly is a dynamically loaded structure ?
I posted a question on another welding forum recently regarding this question and it seems like a good time to throw it out again.
AWS D1.1 2010 references "dynamic loading" three times, once in the Foreword and twice in the commentary.
However, Visual acceptance criteria as per Table 6.1 only lists Static Loading and Cyclic Loading.
My question was would a Dynamically Loaded structure fall under the acceptance criteria of static or cyclic ?
Regards,
Kiwi
RE: welding of dynamically loaded structures
Thus, even though D1.1 has always been obscure about their terminology; Dynamic = cyclic
RE: welding of dynamically loaded structures
Best regards - Al
RE: welding of dynamically loaded structures
Cyclic loads refer to loads that increase and decrease repeatedly in service. These loads remain in static balance with the reaction forces coming from the structure that supports them. Bridges and pressure vessels must support static and cyclic loads. If dynamic loads are applied to them, you can get into trouble very quickly (eg. Tacoma Narrows).
Dynamic loads refer to forces that cause motion, acceleration, deceleration. These loads are reacted by the inertia in the structure or system (in addition to structures that may be in the way). Examples are springs, dampers, pistons etc. You can also consider dynamic loads to involve a certain amount of kinetic energy transfer, such as a hammer striking an object.
I may be speaking from my own background (which isn't exposed to AWS or pressure-vessel codes very often) but I would warn against mixing up the terms.
STF