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  1. edbgtr

    NAS1097 allowables ?

    Here you are guys Regards, Ed.http://files.engineering.com/getfile.aspx?folder=04e17cdf-7303-4958-9311-2b7e29c5fbd1&file=NAS1097_AD_Rivets.pdf
  2. edbgtr

    BUCKLING OF A TAPERED PLATE

    'Morning STF, Thanks for your response and good questions. I applied a uniform stress across the tapered b-edge of the plate. This tied up with the uniform stress assumption one usually makes with this type of flange. If the stress distribution is non-uniform then the buckling coefficient...
  3. edbgtr

    BUCKLING OF A TAPERED PLATE

    StressMan2506, You got me going on this one, and I have done some additional work on the subject, which I think you and others here may find interesting and useful. The work, as you will see, has been bench-marked against published papers and my own FEA. The work I have done is contained in the...
  4. edbgtr

    BUCKLING OF A TAPERED PLATE

    StressMan2506, I have found a reference to tapered flange buckling within a report produced by Y Kim and Teoman Peköz at Cornell University. This work looks pretty well researched and the residing Professor Peköz is well known in the Civil Engineering discipline. To save you the trouble of...
  5. edbgtr

    BUCKLING OF A TAPERED PLATE

    Hi StressMan2506, The work is my own, based on some raw results data (the tabulated coefficients) I obtained and calibrated with my own classical and FE analysis. It is important that such FE based data agrees with classical solutions at the points where it can be tested. The transition of the...
  6. edbgtr

    BUCKLING OF A TAPERED PLATE

    Hi Again Stressman2506, For a typical 2000 series Al alloy, you'll find that the yield stress b/t buckling ratio for a one-edge-free compression panel is close to 10:1. If you apply Needham crippling, this works out at around 8 to 8.5. I.e. it is often used as a guideline for designing...
  7. edbgtr

    BUCKLING OF A TAPERED PLATE

    'Morning StressMan2506, Find attached a chapter from my personal set of stress notes for a stepped flange of 2 thicknesses across the width of the flange. By carefully estimating the "equivalent" flange to the one you have, using the 2 thickness data, you should get a better estimation of the...
  8. edbgtr

    Aircraft Inertia Matrix Data

    tamz1842, At present I am separated from my technical database, on an Ipad, so cannot give you a more complete reply. Part V is the correct item I was referring to. There is other Roskam data on the subject which I have which may not be in the public domain. Part V and its semi-empirical inertia...
  9. edbgtr

    Aircraft Inertia Matrix Data

    Hi tamz1842 Obtain a set of Prof Jan Roskam's books on Aircraft Design. He has a whole book/chapter on the subject of typical historical mass/weight data, including inertia data and cross products resulting from asymmetries. Hope this helps. Ed
  10. edbgtr

    Rib or Frame Stringer Support

    G’Day Eng-Tippers, A question for detail stress engineers regarding stringer beam-column compression analysis. It has come to my notice that new forms of skin stringer construction has led to changes in stringer support conditions at the frames or ribs through which they pass. In the past...
  11. edbgtr

    130 deg Flush Head Fastener Metal Joint Allowables

    G'day Jeff, This is a bit O/T for this thread, nevertheless I'm sure the authorities won't mind me answering your question. If you still have an old DOS machine you'd be able to run the s/w. The new pseudo-DOS will not run PAL. As I recall your machine needed to be free of all other s/w in...
  12. edbgtr

    130 deg Flush Head Fastener Metal Joint Allowables

    Hi Eng-Tippers I spent the day trawling the Internet and found an item relating to this topic that was published in the Journal of Aerospace Engineering. The item is titled, “Influence of Head Geometry on Bolted Joint Behavior”. It appeared in Vol. 15, Issue 4 (October, 2002) of the Journal...
  13. edbgtr

    130 deg Flush Head Fastener Metal Joint Allowables

    Sparweb, Thank you for your words of wisdom regarding this problem. You are quite right regarding my needing some test data for a 130 deg flush head fastener. In the past, I have used known techniques for reverse engineering fastener data to obtain what I need for an application that was not...
  14. edbgtr

    130 deg Flush Head Fastener Metal Joint Allowables

    Wil.. Thanks for responding. The fasteners I have encountered, "Hi-lok" types, blinds and secondary structure bolts, have had large airframer fastener codes allocated to them, so I don't know where they originate from. Most are Ti alloy and in the 3/16 to 1/4" dia. range. Where I work, we...
  15. edbgtr

    130 deg Flush Head Fastener Metal Joint Allowables

    G’day Eng-Tippers, I have a question that a colleague and I are puzzling over. Does anyone here have a method for correcting 100 degree flush head fastener data in aluminium sheet for other higher angle flush head fasteners? My reverse engineering of the sparse 120 degree data in the MMPDS...
  16. edbgtr

    Checking of calculations in the aircraft industry

    Andries, thank you for raising this issue. From the responses one realises that the problem has many aspects to it. I’m sure the problems being highlighted on this thread are being experienced worldwide. I’d like to relate the situation experienced by me with regard to analysis report checking...
  17. edbgtr

    Needham Again

    thread2-222052 Greetings inertia4u (Nert) Did you get a copy of Needham's crippling paper that you requested back in 2008? If you did, would you mind posting it as an attachment here, I'd really like to have a copy of this paper. I cannot find it on the Internet. Can anyone else help out...
  18. edbgtr

    Consequeces of "Knife Edges" with Countersunk rivets

    stresscalcs, The knife-edge (K-E) condition, sometimes known as the feather-edge, is primarily a fatigue problem. The rivet/fastener allowable joint strength tables either in the public domain, or in company manuals, vary depending on their application. Manufacturers of military hardware will...
  19. edbgtr

    Blended-out Surface Damage SCF Reference

    Greetings All I am searching for a copy of the original reference for the information given in Fig. 16.6.1 of Prof. MCY Niu’s book – Stress Analysis and Sizing, 2nd Ed. In particular, I am looking for a copy of the reference for the blended-out surface notch (scratch, gouge, corrosion pit, etc.)...
  20. edbgtr

    Request for Shim/Filler Joint Data

    Steve I did consult the Bruhn text, along with all the other books and data I have accumulated over the years, and precious little seems to have been done and/or published either in the public domain or in company documentation. Using the conservative “Peery Method” during the design phase of a...
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