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Recent content by ABV97

  1. ABV97

    floor beams load due to fuselage pressurization load

    ...we did go to an FEM model, will see how it goes. Thanks all for your thoughts!
  2. ABV97

    Heat treat AD rivets

    I also agree, AD rivets are not hard to be driven, and we have never heat treated them as well! This is dangerous and the repair should not be approved by the authority!
  3. ABV97

    floor beams load due to fuselage pressurization load

    Thank you SWComposite, I think, on top of 6g down ultimate flight load, load of the floor beams due to pressurization should be included as well!
  4. ABV97

    floor beams load due to fuselage pressurization load

    ...well I thought floor beam would react the pressurization load, as a balloon expanding and creating mostly axial tensile loads on the beams. It is B737, with 20' beams pitch, so I assumed a area of A =20 x 40 = 800 in^2, delta p = 9 psi(assumed), P = 800 x 9 = 7,200 lbf. Beam cross section...
  5. ABV97

    floor beams load due to fuselage pressurization load

    Hi All, I am analyzing a floor beam modification and was wondering how can I incorporate fuselage pressurization load on top of 6g down load, no FEM model available? Conservatively stress within the floor beam due to pressurization load would be around 10 ksi, but I need to validate it. Your...
  6. ABV97

    dynamical behavier of weight-added Post Mod beam

    Thanks again rb1957, appreciate your thoughts and time!
  7. ABV97

    dynamical behavier of weight-added Post Mod beam

    Thanks a lot, something to think about!
  8. ABV97

    dynamical behavier of weight-added Post Mod beam

    No, it is a modified beam at the tail, under the APU!
  9. ABV97

    dynamical behavier of weight-added Post Mod beam

    Yes, I was asked that question. I also think, the deflection is quite small and wouldn't be a problem. Last night I was plying with the natural and impulse frequencies showing that they are of different diapason. No history with that type of question unfortunately, thanks again rb1957!
  10. ABV97

    dynamical behavier of weight-added Post Mod beam

    ...no, it's not a helicopter, and under 6g down flight load, due to that Mod, there is a -0.013" deflection, so from that deflection probably I could get the undamped natural period of vibration - I don't know, just still thinking in that direction. If won't work, yes FEA is the next. Thanks rb1957
  11. ABV97

    dynamical behavier of weight-added Post Mod beam

    Hi All, On a modified beam I have statically proved that is OK. However on the beefed portion of the beam, since the weight of the Post-Mod beam is bigger than the original Pre-Mod beam, I was wondering what would be the dynamical behavior of the beam. I am thinking of getting approach to...
  12. ABV97

    Simply Supported (SS) Rectangular Plate Stress Distribution

    ...I am in Bruhn A17.6, hope it will help. Another thing, which a friend recommended me is, to look at it like a cable, and substantiate the end reactions, which might be a problem due to the high end magnitude of this reaction. Hope in Bruhn to find some answer, other than that a stiffeners, as...
  13. ABV97

    Simply Supported (SS) Rectangular Plate Stress Distribution

    ...from all the information I was able to get - Timoshenko Large Deflection of Plates, Roarks, Effects of Large Deflection and Bending of Rectangular Plates with large Deflection Tech Note 846, all large deflection are limited to pb^4/Et^4 = 250 or 300. For my case, this value is 3169, not even...
  14. ABV97

    Simply Supported (SS) Rectangular Plate Stress Distribution

    thanks rb1957, I am on it right now, appreciate your thoughts!!!
  15. ABV97

    Simply Supported (SS) Rectangular Plate Stress Distribution

    Thank you JStephen - I quickly did it, so for 1" wide, 13" long beam, with a w = p*b = 29.61 x 1 = 29.61 lb/in, the bend moment is 626 in-# and stress f = 6*626/(0.071^2) = 745,090 psi, which is relatively close to my 585,184 psi. As rb1957 mentioned, probably my problem would be under "large...
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