Weld Strength
Weld Strength
(OP)
Hi,
I'm trying to determine the strength of a weld in a unique situation, please see attached. I have an aluminum sheet welded to a frame made with extrusions. The sheet is loaded with a pressure that will put a bending load in the welds. I know the bending moments at the welds but I can't figure a way of calculating the stress in the weld, I haven't been able to find an applicable example in any of my textbooks or the web. I think it can be simplified to T-joint with a weld only in one side, but I don't know how to calculate the weld strength for such case. Any help will be greatly appreciated.
I'm trying to determine the strength of a weld in a unique situation, please see attached. I have an aluminum sheet welded to a frame made with extrusions. The sheet is loaded with a pressure that will put a bending load in the welds. I know the bending moments at the welds but I can't figure a way of calculating the stress in the weld, I haven't been able to find an applicable example in any of my textbooks or the web. I think it can be simplified to T-joint with a weld only in one side, but I don't know how to calculate the weld strength for such case. Any help will be greatly appreciated.





RE: Weld Strength
Your point load (magnitude is not labeled!) is on the center of that thin membrane, so the membrane is under tension that will "pull" the center of the membrane down, and the outside edges of the membrane "up" slightly. But you don't have any outside fillet weld around the frame, so you have to go back to the book for "point loads restrained (pinned) all around their edges." there is no moment resistance around the outside, only a shear force and a rotational force around the center of area of the fillet as the center of the membrane goes down and the outside edges of the membrane try to go up.
RE: Weld Strength
Thanks, for the reply. Is there a formula or a mathematical procedure to calculate the strength of the weld in a situation like this? I've attached a simplified example illustration.
To give a little bit of background the frame in the first post simulates a VERY rough example of a shipping container cover. I'm tasked to asses the strength of the covers when loaded with snow. Normally our container covers have stiffeners inside and outside but every container has a different configuration of stiffeners. So I decided that if I remove the stiffeners and prove that the welds alone are sufficient to take the load, obviously the stiffeners will only make the weldment stronger.
RE: Weld Strength
RE: Weld Strength
What engineering reference do you have for membrane stress?
RE: Weld Strength
RE: Weld Strength
But your example image file shows a point load at the center of the plate.
RE: Weld Strength
RE: Weld Strength
I would expect there to be significant stress concentrations around the perimeter of the sheet with the weld joint shown in the second sketch. There is an abrupt change in stiffness at the transition from the sheet edge to the weld and to the frame.