Effective Plate Width

[ul92]

Good day Everybody,

I am writing concerning with effective plate width. As shown in the attachment a plate in 10 mm thickness is simply supported by two sides. Load is applied through 4 rectangular upper plates which are not welded or fixed onto the main plate. For section modulus the effective plate width has to be defined which i think can be defined with 45 deg method.

What are your thoughts?

P.S. For sure,the most easiest method is FEA but checker is not much familiar with the fea thing

Thanks

 

[JStephen]

I'd probably just check bending moment on a line down the center. I don't know that you could really say for sure that any other assumption is really any better, and if you're going to approach it on that kind of basis, you might as well make it a simple assumption.

 

[BAretired]

Dimensions are not shown, but the effective width shown on the sketch, assuming it is to scale, seems a little conservative to me. A yield line analysis might be worth trying; I suspect it would show the critical yield line to be as described by JStephen.

BA

 

[ul92]

Prior to posting this i checks ''Roark's formulas for stress and strain'' and found only one case which was same fixing scenario but knife-edge load in the middle. Is there any other references that I could be looking at?

I have already run a FEA and effective width shown on previous attachment is somewhere coincides with FEA result but deflection turns up differently around 4-5 mm.

 

[transmissiontowers]

I have used 12 times the thickness as an upper limit to the length of the bend line for point loads like bolts in tension or compression. If you shrink your distributed load down to a point and make the plate infinitely long, you would not use the entire plate length for a bend line down the middle.

There is an old book by Omer Blodgett called Design of Welded Structures from the Lincoln Arc Welding Foundation that has a lot of good info on steel design. Section 6.6-6 has an equation where the effective width is taken as 12t.

We have assumed a 6t limit on either side of a point load for cases where the load is near an edge of the plate in bending.

My copy of the Blodgett book was published in 1966 probably before there were many FEA computer programs out in the real world.

_____________________________________
I have been called "A storehouse of worthless information" many times.

 

[Tmoose]

Does each of the 4 load rectangle represent an independent distributed load,?
Or, is there a structure or component with 4 rectangular legs resting on the 10 mm plate spanning the I beams?

 

[manstrom]

If it is metal deck with concrete topping, there are equations for the width from the SDI.

When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.

-R. Buckminster Fuller