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  1. Worldtraveller

    Inserting image in MathCAD prime 3.1 cause...issues.

    I am using MCAD Prime 3.1 at work. I have a couple of issues with it so far. (I have lots of experience with MathCAD prior to PTC, and still run that for my own business.) 1) When I copy/paste an image from word or drag and drop it into the MCAD file, it won't let me save the file after that...
  2. Worldtraveller

    Looking for a reference

    I have, in the past, read at least a couple of engineering related books (as opposed to scholarly theory) about applying FEA to various structures. In general, if possible when modelling aircraft structure, it is better to use 'lower dimensional' elements. This is the generally accepted means...
  3. Worldtraveller

    Structural Shim

    1) Shims in aerospace applications don't have to be tapered. 2) The term filler and shim are more or less interchangeable in most cases, especially with repairs. So the terminology can get a bit confusing. 3) A structural shim, in this case would have to extend one row of fasteners further...
  4. Worldtraveller

    FAA involvement with KC46 certification ?

    rb1957, that's typical of how the FAA operates with military programs. They help with the certification, then the OEM adds exemptions as needed to actually operate the aircraft in the designed manner. It's not silly, so much as practical considerations that the aircraft operates in an airspace...
  5. Worldtraveller

    Fatigue life of 17-4PH H1150 bar

    You might have to get a subscription to IHS or a similar service to find what you're looking for. I don't think that data exists for that particular HT/Alloy, so you would either have to do the experiments (long and time consuming) or find a way to justify using a similar alloy/HT. My company...
  6. Worldtraveller

    Bulkhead-Longeron Connections?

    Most General Dynamics designs would have continuous longerons with cutouts in the BH to allow them to pass through. This is based on fairly recent designs I've seen from GD, and their design handbook from the 70s.
  7. Worldtraveller

    Highest Recommended Edge Distance

    The min is 2D for metals. I think the standard is 3D for (most) composites. There's no general max for metals because it would be (as rb notes) mostly dependent on the configuration and loads. For a composite floor panel, you would not want too much E/D mostly because you want floor panels...
  8. Worldtraveller

    Likely causes of porosity in composite parts that use an autoclave

    My experience with composites is fairly limited, but varied (solid laminates, honeycomb panels, of AL-Al, Carbon, Kevlar, and glass). I assume when you talk about porosity, you mean in a solid laminate? The number of plies (and total thickness of the part), the pressure used, the minimum...
  9. Worldtraveller

    Louver Sizing Question

    It seems would at least need something feeding air into the area to be cooled for this to work. Just have an exit near a low pressure area would reach semi-stable equilibrium without a way to flow air into the area from elsewhere (maybe you have that already, but it wasn't mentioned). As...
  10. Worldtraveller

    MathCAD Prime Express 4.0

    SMath equations copy into word as images, which is at least easy to deal with.
  11. Worldtraveller

    MathCAD Prime Express 4.0

    On the plus side, SMath works just like the 'old' version of MathCAD, so thanks again for that tip. I had never heard of that software before.
  12. Worldtraveller

    MathCAD Prime Express 4.0

    Prime 4.0 won't copy/paste into Word. Glad I got the free version first. I guess I'll be uninstalling this from my machine. Now to go find a feedback form in case they care. :) I still use my old version on my own machine, but this new version is like learning a completely different software and...
  13. Worldtraveller

    Do finite elements have to be planar?

    A single element should only be non-planar if it is a 3D element. Is that the question you're asking? 2D elements by definition should be planar.
  14. Worldtraveller

    Honeycomb Sandwich inspection

    SWComposites, I have some references, and since I work for an company that is a .edu, I have access to a lot of research and some industry studies. I've now got 4-5 papers that I'm going to start going through. Any additional references are welcome though. I've got a fair bit of industry...
  15. Worldtraveller

    Honeycomb Sandwich inspection

    I'm helping write/review the process specs for some of our repairs, particularly with regard to composite (solid laminate and honeycomb). We have a very old spec that just says, "Inspect for moisture and corrosion." <--- That's not vague at all. It doesn't call out a process or process spec...
  16. Worldtraveller

    NAS bolt with tension nut

    I suspect there aren't really any issues with the installation as you describe it. You are probably within the nominal installation for this nut/bolt combination. I'm not sure you'd detect the incomplete threads if you continued to tighten the nut, since there is good threading through most of...
  17. Worldtraveller

    MathCAD Prime Express 4.0

    Thanks for the tip on SMath. I'm going to send the link to the IT guy and see if he has any objections to me installing it on my work machine. That seems a better option at this point than trying to get an expensive license for software that's just annoying me.
  18. Worldtraveller

    Discrepancy in formula for ring doubler in shear web?

    I always forget that there are more than one, but we were actually referencing both Airframe Structural Design (1st edition) and Stress Analysis for Airframe Structures (2nd edition). I eventually just sat down and drew all the freebodies, and it turns out that the way Nui and Flabel use P is...
  19. Worldtraveller

    FAA involvement with KC46 certification ?

    I am not involved with the KC46 in any way. However, I worked on the production line of the military's primary trainer, the T-6 (A, B & now C models) for over 8 years. That aircraft was a modified Pilatus (PC-9) and the certification was also coordinated through the FAA. In theory, that aircraft...
  20. Worldtraveller

    MathCAD Prime Express 4.0

    I don't have any issues getting it (MCP 4.0) to run on Win10. I just hate that they completely changed the keyboard interface and none of the 'normal' mathcad keys work to write equations. I really only use MathCAD for basic algebraic stuff and rarely need anything more advanced than a simple 2D...

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