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Diagonal tension of rectangular plate with a central unstiffened hole

Diagonal tension of rectangular plate with a central unstiffened hole

Diagonal tension of rectangular plate with a central unstiffened hole

(OP)
Hi,

Can anybody help me to find some information on diagonal tension analysis of a rectangular plate with a central unstiffened hole(s).

RE: Diagonal tension of rectangular plate with a central unstiffened hole

You have equations in

Gide to Stability Design Criteria for Metal Structures 4th edition
edited by Theodore V. Galambos
around p.115

The same, 5th edition, around p. 151

I once posted some worksheets doing this tasks and other related to web openings but are not available anymore since it seems was against the forum policy.

Best wishes

RE: Diagonal tension of rectangular plate with a central unstiffened hole

(OP)
Thanks ishvaaq, is there a possible way for me to look at those worksheets? Until I take that book out from the library, can you tell me whether assuming an effective thickness of the panel without a hole and applying the Bruhn diagonal tension analysis will work?

RE: Diagonal tension of rectangular plate with a central unstiffened hole

http://books.google.es/books?id=W_a0-8wiHdwC&pg=PA151&lpg=PA151&dq=Galambos+Stability+Design+Criteria+Web+with+Holes+Under+Combined+Loading&source=bl&ots=xPak20w-fF&sig=ut8-rM5kC3gC07Myvw2DM4rXvic&;hl=es&;ei=wP6kStOcHprajQfctvioDg&;sa=X&oi=book_result&ct=result&resnum=1#v=onepage&q=&f=false

This opens the book right more or less where wanted.

Respect the availability of the worksheets (Mathcad's) I think I posted most of them at the Collaboratory of Mathcad 2000, but I think presently public access to such site is not public anymore after Mathsoft's purchase by PTC.

I may however give a try to your specific case and see how well it fits the worksheets and see what are the results, and comment.

Those not based in Galambos' I think I based on a pair of articles on AISC's web openings steel design guide 2, 1st edition, which must be readily available.

RE: Diagonal tension of rectangular plate with a central unstiffened hole

(OP)
Ok, lets say a panel 508mm by 189mm with two central unstiffened holes of 76 mm each 200mm apart. Thickness of the panel is 3mm and the boundary conditions are: short side fully clamped, one long side clamped, one simply supported. The applied shear is 250 N/mm.
Let me know if this is enough info.

Regards,

Steven

RE: Diagonal tension of rectangular plate with a central unstiffened hole

From your description I think the web opening approach from the guide will be less applicable; anyway will look. Of what you are giving to me and checking the implementation of Galambos IV I have, I am finding as of now that on the one hand we have not one ciruclar opening but two, and even simulating them as a rectangle (what is overly conservative, surely too much) the conditions that I have described in the worksheet, that exactly match I think those given in the book do not conform to your restraint. I also precise to know if the 200 mm are between hole centers or closer quadrant points. As well, since 3 mm thick, I understand the applied (factored) shear stress is 250/3=83.33 N/mm2.

With just the 4 sides supported that would give (for the long rectangle having the circles within and 200 mm between centers) a 3.95 check where we would need to have at much 1.

We are not done. Since the procedure to get the applicable critical shear stress with holes is a function of that without holes by the Galambos' quoted formulation, we may still find such stress with your proper constraints looking elsewhere; I will.

Also, some 3D model able to enter in the postbuckling strength would give the thing; those elastic, not as you pretend. Let's continue looking.

We may have

RE: Diagonal tension of rectangular plate with a central unstiffened hole

(OP)
Hi ishvaaaq,

To answer your questions, I have already obtained the shear buckling allowable with centre unstiffened holes using Fokker TH3.906. You are right, the applied shear stress is 83.3 N/mm^2. So it is clear that the panel should buckle under these conditions.
My question is:
What analysis can be done now to determine how the shear is distributed to the surrounding structure and whether diagonal tension analysis as per Bruhn is in fact applicable. I do not understand what you mean by 3.95 check, but I have not gone through Galambos yet.
Definitely FE analysis should be done.    

RE: Diagonal tension of rectangular plate with a central unstiffened hole

Well, I assumed Fy=260 MPa and then the applied shear stress to the shear critical stress with the holes so modeled gives ratio 3.95 in the above described conditions. Of Bruhn I can't say since (as always, and more here where so many of many fields are present) I am not particularly an expert and just try to answer what my path through my studies and practice have permitted to learn.

After reviewing somewhat the book and papers I have (UBC on aluminum, plate buckling os naval structures and eurocode  steel for buildings between them) I don't find readily nor a case with your constraints, less the exact kind of geometry, then I also think that if available a FEM analysis will be the more sound approach.

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