Bolt Preload in FEA Guide using Femap

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  • Опубликовано: 22 авг 2024
  • You can learn more about bolt preload here: enterfea.com/b...
    Learn more about FEA in my free FEA course: enterfea.com/1...

Комментарии • 26

  • @beefybeef1326
    @beefybeef1326 4 года назад +1

    Very useful clip. And nice to see Stephen settling in well.

    • @Enterfea
      @Enterfea  4 года назад

      Thanks! We are doing our best to help him feel like a part of a family :)

    • @beefybeef1326
      @beefybeef1326 4 года назад +1

      @@Enterfea I look forward to seeing him in future videos.
      I'm curious, would it be possible to model 2 plates bolted together, like a lap splice with sloppy bolt holes in each plate with preloaded bolts clamping the plates together. The thing I would be specifically interested in is predicting the friction load capacity of the joint, that prevents slippage of the two plates when an end load is applied to lap joint. I wonder if a non linear run would predict the slip load which agreed with test data....

    • @Enterfea
      @Enterfea  4 года назад

      @@beefybeef1326 I'm afraid that in such a case, one of the very important inputs into your model would be the friction coefficient in contact. And as far as I know, you need to have it from experimental data. I'm not sure if you can actually calculate what a friction coefficient "will be" in your model. Perhaps in some crazy advanced way, I'm unaware of, but I'm not sure how estimation like that would work... In other words, you can make a really accurate prediction, as long as you can very accurately know the friction coefficient at the start. Without knowing it, I'm not sure if you would be able to "get it" from FEA.

    • @beefybeef1326
      @beefybeef1326 4 года назад

      @@Enterfea thanks for your reply. I already have the friction coefficient from test coupons and was going to use it as an input, and I agree that this coefficient is only available from test data. I was curious if the model would predict when slip actually occurs, and how well that calculated slip load compares to the test. Now I think of it, its probably a silly question because limit friction force = u.R, where R is the reaction force at the contact plane ( for this case it will be bolt preload), when the applied end load is equal to u.R slip occurs. I think it would get interesting in the scenario where there is some loads on the model that result in preload relief on the bolts which would reduce clamp up of the joint and bring on the onset of slippage sooner.
      Thanks again for your messages

    • @Enterfea
      @Enterfea  4 года назад

      @@beefybeef1326 I think it's good to ask all the questions one has. Even if they seem silly later. I know I definitely asked (and still do ask!) a lot of silly questions. This is how we learn after all.
      To answer your question, I think that the correlation between lab tests and FEA can be really good, but I admit I never tested friction in this particular area.

  • @HCwinckler
    @HCwinckler 4 года назад +1

    Great video, thank you.

    • @Enterfea
      @Enterfea  4 года назад

      I'm really glad that you like it :)

  • @ivicailic849
    @ivicailic849 2 года назад +1

    What is proces when thread of bolt is all in the material? Meaning that there is no nut on bolt. How to create such a cinnectiom using a bolt as a solid body? Hope you understood me.

    • @Enterfea
      @Enterfea  2 года назад

      Hey! Well., the bolt preload will be applied the same way, although I don't think this is what you have in mind.
      For the "how to model your case" this only depends on the level of detail/accuracy you need. I would guess that you either "just connect the nodes" of plate and bolt (so there is no thread... as if this was all welded), or you model thread and contact and all that (I guess there are situations where this is needed.
      Still., I have little experience in this, in structural steel this is not a used connection, and we always have nuts and washers and all... so I didn't have to worry about this particular problem much...

    • @ivicailic849
      @ivicailic849 2 года назад

      @@Enterfea by "connect the nodes" You mean to merge coincident nodes or something else? I found out that for solids is preferable to use GLUE contact for this type of connection (where thread of bolt is whole in materail). But i am confused, becouse i need to apply bolt preload on those conections, and if I use glue contact i think that it would not work like in Your examples.

    • @Enterfea
      @Enterfea  2 года назад

      @@ivicailic849 I think you can use glue contact or merge nodes... from the bolt preload it should be the same I think, but as I don't have need for doing something like that, I have to admit I didn't test that so far.
      Good luck!

  • @ivicailic849
    @ivicailic849 2 года назад +1

    One more question, would bolt preload in case of solid when model is meshed with tetMesh?

    • @Enterfea
      @Enterfea  2 года назад

      To be honest Mate... I don't know. I'm not a big fan of TET mesh (at least TET4)... and I simply haven't tested that. I'm pretty sure this is "foundable" (at the very worst, ask your local Femap reseller) - sadly I can't give you a definite answer here.

  • @SuperVatex
    @SuperVatex 2 года назад +1

    Hello! Great video. I can't break the bolt so perfectly into six "HexMesh" faces. It turns out to be broken only into triangular elements of four faces, but in this case Bolt Preload does not work. How to break the bolt body into elements with a mesh from the center, like yours? Is there a video? Tell me, thank you.

    • @Enterfea
      @Enterfea  2 года назад

      Hey! There isn't a simple way to explain how to do this, but I think that in most FEA systems if you mesh the "top" and the "bottom" section of the nut (the hexa shape) with quad elements (2D elements) you can then ask the mesher to do "those elements along with thickness" of the solid as 3D bricks. Of course, the mesh on the top and bottom has to be the same.
      All the best!
      Ł

    • @SuperVatex
      @SuperVatex 2 года назад +1

      @@Enterfea Thanks for the prompt answer, I understood the essence of your answer, such a division into elements is performed by extruding solids from elements of a two-dimensional grid.

    • @Enterfea
      @Enterfea  2 года назад

      @@SuperVatex I'm glad that I could help you a little :) All the best!

    • @SuperVatex
      @SuperVatex 2 года назад +1

      @@Enterfea Happy holidays!

    • @Enterfea
      @Enterfea  2 года назад

      @@SuperVatex for you as well :)

  • @Zarizqi
    @Zarizqi 4 года назад +1

    hi sir, thank you for this tutorial. but i have questions about my leave spring analyze in femap. but the surfaces of me leaves spring can't contact each other so the analyzed can't be running. do u know where is the problem ? thank u so much

    • @Enterfea
      @Enterfea  4 года назад

      Hey Liza... sadly I'm not sure what are you doing by your description :( Sad thing is, that in order to help someone with "how to fix something in my analysis" I would have to know a lot more about it, and analyze the problem myself most likely...

    • @Zarizqi
      @Zarizqi 4 года назад

      @@Enterfea well it's okay sir. I have finished my analysis. Thank you for the tutorial

  • @mangeshjadhav9134
    @mangeshjadhav9134 4 года назад +1

    Sir what contraints is to be given in ABAQUS if we are simulating bolted connection beam column joint ...please mail me or reply here...i want it for my disseratation work

    • @mangeshjadhav9134
      @mangeshjadhav9134 4 года назад

      mangesh.jadhav67@gmail.com

    • @Enterfea
      @Enterfea  4 года назад

      Hey. First of all, if this is a dissertation... ask your tutor - it's literally his/her work to help you out with this! Apart from that, I have no clue what you want to achieve, what the goals are, how the model looks etc. It's an impossible question :( But if I would have to make a guess, I would model beams and columns with 2D plate elements, and model bolts as beams with contact where needed (just make sure to model some rigid circles where bolt connects to the plates, not to attach it to a single node...)