Impact Design of Fillet Welds
Impact Design of Fillet Welds
(OP)
I have to design a fillet welded connection that will subject to a 10kJ impact force. I am concerned that the limited ductility of the weld will affect the available strength of the weld not allowing it to reach its full potential.
Does anyone know of any design guidance that will help me calculate the actual weld capacity under impact?
Does anyone know of any design guidance that will help me calculate the actual weld capacity under impact?
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RE: Impact Design of Fillet Welds
I think you need to find the actual force that your imparting onto the weld and not just the energy of the impact.Have a look at this site for weld calculations anyway it might help:-
ht
regards
desertfox
RE: Impact Design of Fillet Welds
There is a significant amount of data on weld metal toughness (impact energy, J or ft-lbs, as a function of service temperature) to assure adequate fracture toughness. The load-carrying capacity can be calculated for fillet welds and groove welds (I would refer you to Design of Weldments, by Omer W. Blodgett for additional reading on this subject). This is the reason why I was asking the second question - will this be repeated peak loads or a one time peak force.
RE: Impact Design of Fillet Welds
I am concerned that I will get a fracture at the weld because of its lack of ability to deform with the load. To my way of thinking this will lead to a higher instantaneous force in the weld when compared to the static load case. I guess I am thinking in terms of impulse.
RE: Impact Design of Fillet Welds
RE: Impact Design of Fillet Welds
RE: Impact Design of Fillet Welds
I might be missing something here but if you have stressed your welds statically with a good margin of safety I do not understand how you can be concerned about it failing.
what are your margins of safety in the welds?
regards
desertfox
RE: Impact Design of Fillet Welds
Why are you assuming that the weld will not deform with the rest of the structure? That seems counter-intuitive. Part of the qualification of a welding procedure is to demonstrate toughness (Charpy), strength (tensile strength) and ductility (bend tests).
Steve Braune
Tank Industry Consultants
www.tankindustry.com
RE: Impact Design of Fillet Welds
Blodgett provides the necessary information regarding what is an impact force, properties of sections with equations and most importantly impact properties of common design materials. An excellent resource book.
RE: Impact Design of Fillet Welds
Steve, the main reason I was concerned comes from speaking with colleagues. The example cited was if you are on site and wish to remove a piece of fillet welded steel you just hit it with a 14lb sledge. Because of limited ductility of the weld the section will not deflect but just snap off. I spoke with our materials department and the told me the Weld Qualification Procedure Tests do not usually cover ductility testing for fillets only butt welds.
RE: Impact Design of Fillet Welds
The fillet weld does not necessarily have "limited ductility". The root of the fillet acts as a notch. Flaws in the root, often undetectable, exacerbate the effect of the notch. If the joint is designed appropriately, and the weld is made to preclude flaws in the root, failure at the applied dynamic load can be negated.