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Recent content by sdar79

  1. sdar79

    Error can't create new drawing sheet

    I'm working on a model with several drawing sheets already created. Now when I attempt to create a new drawing sheet in the drafting module, it gives an error stating "A buffer was overwritten by the TEXT module" and does not work. If I erase all of my previous sheets, it works, but I don't want...
  2. sdar79

    Drafting can I hide/show groups in a drawing view?

    I have a model file (not an assembly) that contains a number of bodies that are all sorted into groups. NX 1872. I'm creating the 2D views in Drafting now. I need to show several drawing views that contain varying combinations of groups. Is it possible to show and hide groups in an individual...
  3. sdar79

    How to size stiffeners?

    Hey all, I was able to find someone with a copy of Niu. Specifically chapter 14 held what I was looking for. Turns out, our OEM manuals do have a procedure for each of the individual steps, but had nothing which say "do these steps when designing a stiffener", which is where Niu was very helpful.
  4. sdar79

    How to size stiffeners?

    I'm in the maintenance world where we usually design to original capability, but am working on a small mod now where I can't keep the original geometry. This particular panel is mostly shear/tension loaded, but it got me thinking that I don't know how to size stuff if it were a compression...
  5. sdar79

    How to size stiffeners?

    Let's say I have an aluminum skin, carrying a compressive load over distance "a" from frame to frame, and supported by longitudinal stiffeners equally spaced at width "b". I am sizing everything, having the required loading in lb/in. After selecting a skin thickness I can get the buckling stress...
  6. sdar79

    Bolt hole eddy current inspections

    Yes, hole quality isn't always the best, but for a 30+ year old airframe it doesn't seem to have caused many problems. A couple other examples: I had one with 3 holes showing flawed, oversized the 3 and when NDI rechecked they marked 6 holes as flawed (some that were good just hours before). Or...
  7. sdar79

    Bolt hole eddy current inspections

    We have been transitioning a lot of our NDI procedures to remove fasteners and inspect with bolt hole eddy current. A lot of them are through stacked structure, say 3 layers of aluminum that are not taken apart. We are getting a lot of what I'll call false positives, crack indications that...
  8. sdar79

    Help me understand the difference between crippling and buckling

    Thanks everyone for the input. I understand it a bit better now.
  9. sdar79

    Help me understand the difference between crippling and buckling

    Let's assume an integrally stiffened I-beam under axial compression. As I understand it, the free-edge flanges will buckle first. As load continues to increase the corners and web will eventually buckle. The crippling stress Fcc of this test sample is basically then a P/A, an average stress of...
  10. sdar79

    Freeze plugs

    Does anyone know of any good references to use for freeze plugs? I'm looking for something that covers aluminum, titanium, and steel alloys and the primary use is for repairing bad fastener holes in aircraft structure. I'm looking to find: - the appropriate amount of interference to use with...
  11. sdar79

    Data for PH13-8MO in solution treated/annealed condition

    Is there any published data to go by for PH13-8MO in the solution treated/annealed condition? MMPDS and the other references we have in our office say that 13-8 should not be used in this condition but do not say why. We have some CSI's on our aircraft that should be heat treated to the H1000...
  12. sdar79

    Knife-edge fasteners in bonded stackups

    On typical sheet metal structures, we want a fastener countersink depth to be no more than 2/3 of the part thickness to avoid a knife-edge condition. Let's say I have a single part made of three sheets of .040 thick material that are bonded together to give a total stack up of .120 thick. I want...
  13. sdar79

    Thicken surface by varying amount

    Thank you very much. The "variable offset" in your file is the tool I was looking for, but I did not know I had to enable it to show in the menus. I found it using the command finder.
  14. sdar79

    Thicken surface by varying amount

    7.5
  15. sdar79

    Thicken surface by varying amount

    I am modeling a wing skin which has the outer surface defined by loft data that I have a surface model for in NX. Some areas of the skin have a tapered thickness, ie, tapering linearly from say .180 thick at one point to .120 thick further outboard. What's the best way to model this? I am trying...
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