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How to check the plate with concentrated force?

  1. Feb 1, 2016 #1
    Hello all,
    I have a question about the plate with two edges fixed by weld and subjected to lateral conconerated load, as the following picture shown, I am not very familiar with plate theroy, Could you give me a soluation about this weld?
    Given,
    L1 Weld 1 Length
    L2 Weld 2 Length
    t Weld throat
    Ft Lateral load
    L3 Force arm to weld 1
    L4 Force arm to weld 2

    Soluation
    The weld stress

    Thank you.
     

    Attached Files:

  2. jcsd
  3. Feb 1, 2016 #2

    Nidum

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    The drawing comes up on screen too small to see properly .
     
  4. Feb 1, 2016 #3
    Hello, Nidum
    Thank you for your comment.I have made a PDF file, please find the attachment and give your solution.
    Thanks again.
     

    Attached Files:

  5. Feb 2, 2016 #4

    Nidum

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    Having studied your drawing I regret that I must decline to help further .

    The design does not seem to be based on sound engineering principles and in any case there is not enough information given for a proper analysis .
     
  6. Feb 2, 2016 #5
    I was a welder and fabricator for years and based on the drawings you provided there is just not enough information included to really see (visualize in detail) any proper load bearing area. Just from the drawing it looks like a stand off lifting lug. You have a lot of different things to consider, weight, lateral stress, axial stress (x,y,c) material tensile strength and welding process itself. Anytime you weld a piece of metal you heat it to the melting point and each times is cools the crystalline structure of the metal itself changes (ie it hardens and becomes more brittle) You should probably take a few detailed pictures of a finished product point out all fillets and describe your process, gaps, angles penetration depth ext. It is being welded to code? if so what standard? ASME ext.
     
  7. Feb 2, 2016 #6

    berkeman

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    The drawing doesn't make sense to me -- the 3 views don't seem to be consistent with each other...
     
  8. Feb 2, 2016 #7

    Nidum

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    It took me a while - I think the L shape is a view of the weld bead detached from the structure .
     
  9. Feb 2, 2016 #8

    berkeman

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    Ah, that helps some. But his front view and bottom(?) views don't seem to match either. It looks like there is some sort of a base in the front view, that is missing in the bottom view...
     
  10. Feb 2, 2016 #9

    Nidum

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    This bracket must be attached to something so I would expect to see some bolt holes .

    The fact that the load appears to go from thick section to thin section to nowhere was my main concern with this design .
     
  11. Feb 2, 2016 #10
    Sorry for miss information and not clear description.
    This is a interface joint, we supply the main plate, the back structures are supplied by others, so bo be safe I need to ensure the plate can hold all force, I know it is not good to subject the lateral load, but I have no other choice, so need some stiffener.
    But now I need to konw how much the stress on the weld which block me a long time.And then I can decide the stiffener size.
     
  12. Feb 2, 2016 #11
    Thank you for your guidence.
    And sorry for miss information and not clear description again.
    This is a simple sketch,I remove a lot of thing for clear,and I am foucs on the strength, the fabrication detail will be added later.
    This is based on AISC rules, probably similar with ASME, can you show me which part of ASME I can find the related requirement?
     
  13. Feb 2, 2016 #12
    Sorry for miss information and not clear description and thank you for your attenation.

    The L view is intened to show the weld seam information.This is a interface joint, we supply the main plate, the back structures are supplied by others, so bo be safe I need to ensure the plate can hold all force, so I remove the base in the bottom view.
     
  14. Feb 2, 2016 #13
    Totaly agree with you.One part of the force will go to weld 1 and the other go to weld 2, but I don't know the exactly percent data. And I look up the thick plate theroy, it is very complex, I thick somewhere will show a moment disbutriction factor.
     
  15. Feb 3, 2016 #14
    http://www.gowelding.com/wp/asme4.htm

    I will tell you from experience welds subjected to loads (if they fail) tend to break at the edges this is true for most types of welds with the exception being socket welds subjected to torque. And tig welds that are fused without filler, (they sometimes break right in the middle). Good penetration and adequate procedural guidelines should be sufficient to avoid a weld failure. My old foreman use to tell me 'if you aren't confident in your finished product don't put your stamp on it". In other words review your steps and have a foreman or Quality control specialist check it before you stamp it. It will pass that way.
     
    Last edited: Feb 3, 2016
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