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  1. dcascap

    How to determine G12 if I have E1, E2 and v12?

    No, you are using an orthotropic material model the one that you're using so you need to know it. Which type of composite are you using? Check some typical values for a similar composite and use that. Example: https://www.performance-composites.com/carbonfibre/mechanicalproperties_2.asp
  2. dcascap

    Shaved CSK NAS1097 rivet strength allowables

    Just fyi to this post (don't know if important) but the updated HSB (2020) took out some sections that you were referring to at the start (specially for CSK rivets), as CSK joint allowables come mostly from test... Don't know the reason as I'm not part of the committee, but what I have seen is...
  3. dcascap

    RAPID Software Manual Official Link?

    fyi RAPID is not approved for DTA evaluation of cutouts anymore. If you want to use it as a guideline or to understand the procedures you could use this: https://apps.dtic.mil/sti/pdfs/ADA416231.pdf
  4. dcascap

    Overtightening a bolt beyond its recommended bolt load.

    I agree with you, I assumed that they wanted to increase the preload due to the calculations they made. But it's true what you say and they should ask the supplier for more info.
  5. dcascap

    Overtightening a bolt beyond its recommended bolt load.

    Here you are. Temperatures are in page 83, preoad page 100 https://new.bremick.com.au/images/site/PET_PC_web.pdf
  6. dcascap

    Overtightening a bolt beyond its recommended bolt load.

    You are right, I miss copied the value in excel. The tensile area is 2854 mm2 ( a bit lower than you said due to the threads etc). Yield 2054 kN Tensile 2454 kN Then if you preload 670 kN should be alright is around 30% yield. You're in the spec service temperature range -100˚C to 565˚C so...
  7. dcascap

    Overtightening a bolt beyond its recommended bolt load.

    Min Yield strength of this bolt is 720 MPa, tensile is 860 MPa. Tensile area is A= 645.16 mm2 Therefore Min yield load is 464.8 kN Max load is 554.8 kN So the recommended preload is 90% of yield strength. If you preload to 670kN you will probably break it before reaching the load. Hope it helps!
  8. dcascap

    JetZero Blended wing proposal

    Probably they will ask more money later... it feels like most companies do the same, promise impossible deadlines with less budget and then when the deadline approaches they ask again money and continue... But idk it's a demonstrator so it could be possible depending on how advanced were in the...
  9. dcascap

    FEMAP User Computed Vectors

    I've always used the default names... but I hope someone can help because I'm also interested on it
  10. dcascap

    The incredible evolution of the PGM-17 Thor Missile to Thor-Delta and finally Delta

    Quite cool, thanks for sharing!
  11. dcascap

    Standard for keys and keyways/keyseats design (Aircraft)

    Maybe move this post to Aircraft Engineering as they could help you more with it. From my side I'm not aware from a MIL spec for it but I'm not experienced on this. I guess a simple requirement is to use aerospace graded stainless steel (MMPDS) to avoid issues. Regards, DCC
  12. dcascap

    SOl103 modes slow

    Hi all, I have a model which is a sandwich CFRP panel connected to a support structure, with around 300.000 nodes. The 4 connection between the panel and support structure is modeled with RBE2 and spring elements. Depending on the stiffness of the spring the sol103 significantly differs on...
  13. dcascap

    Solid elements rotations in FEA

    Yes it is as the nodes are freely to rotate so the stay in 0. Femap and Nastran only plots the Nodal translations and rotations. There is no element translation or rotation. As Dave said, you don't really solve rotations to calculate strains, as the strain is mathematically a derivative, and...
  14. dcascap

    Solid elements rotations in FEA

    First of all, you can get the nodal rotations, but there is not really element rotation. As Dave already mentioned, for solid elements the rotational DOFs at the nodes don't make sense due to the solid formulation as they don't have bending stiffness. In a nutshell, for plate elements you have...
  15. dcascap

    Blind rivet tension allowable

    Hi Wil, Sorry for the delayed answer. I was asking due to encounter of this guideline which I found and it's widely used in my company. I am evaluating with blind rivets due to the nature of the component, and these rivets do encounter tension due to some secondary bending (it's a beam of a...
  16. dcascap

    Blind rivet tension allowable

    That's a good one, probably there is a relation between them, I'll reread the Mccombs supplement to check, thanks!
  17. dcascap

    Blind rivet tension allowable

    Thanks for your comments SW and WK, it does not specify any spec, only "blind rivet", I re-read the methodology, and it said that this reduction factor comes due to the fact that there is no mention on how much the fastener yields and deforms before it reaches ultimate load. But in my opinion...
  18. dcascap

    Blind rivet tension allowable

    Yes, that is true but this failure only refers to the fastener itself (its a calculation method in which Ft of fastener = 0.2Ft for blind fasteners, on the other hand, for Hi lok there is no tensile reduction) other joint failures are evaluated later on. The guideline correspond to a handbook...
  19. dcascap

    Blind rivet tension allowable

    Hi, I came across a guideline that ask for a tension allowable reduction k=20%. So the new tensile allowable would be 20% of what the vendor (as cherrymax) specifies for that blind rivet. Have you encounter similar guideline? I understand that blind rivets should not be designed to be used in...
  20. dcascap

    NAS517 tensile strength

    Thanks both of you for your answers and tips, it clarifies a bit better where and what do I need to look :)

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