Hypermesh Bolt Pretension Analysis [Optistruct Tutorial]

[@PauloNeuenschwander]

Amazing tutorial man! I wish all Altair tutorials were like yours!

[@Aeroswap]

Thanks Paulo! Glad you liked the tutorials :)

[@raavan9krockers309]

Thank you sir for your hardworking mannaer, could you please provide us any report so it can be very much useful to us

[@anilchaurasiya2103]

Good one, one quri what about orientation of the pretension load why you left the colum blank.

[@onkarjalkotkar5647]

Really This tutorial so helpful for me.

[@Aeroswap]

Good to know!

[@jagdishkumar-e7n]

can we have multiple bolts pretension defined under one subcase?

[@amoghmangalam3130]

Good, why RBE 2 elemtns not taken for modeling a rigids spider They can also give 1 D beam element later on ??

[@NishankDevaiah]

Are the CAD models unavailable/have been removed?

[@harrymaybourne4274]

Perfect video ! RBE 2 element with additional rigidity can avoid hole ovalization?

[@Aeroswap]

Thanks Harry! Yes, using RBE2 will prevent shape change of the bolt holes but it will also result in some stress concentration zones along the free edges. Finally it comes down to the analyst whether to use RBE2 or RBE3 :)

[@kenkim2687]

Nice to see how the pretension affects the bracket. This case RBE3 is sufficient to idealize the bolt pretension and its load distribution around the holes. I guess in reality you could also include the bolt head area by adding more RBE3 independent nodes. I'd be curious to see how the stress changes when using solid elements for the model with the contact assigned.

[@Aeroswap]

Hey Ken! Yes, much more detail can be worked into this. It is also possible to add washers on both sides of the bolt and see if the stress pattern changes. It would be great to see the comparison between 1D bolt and 3D bolt with contacts defined. Maybe I will work on a follow up video with these additions soon :)

[@cxg5654]

Your video is great, thank you so much. Regarding the bolt preload, I would like to ask how to realize the transient analysis after bolt preload? Proceed as follows: 1. Add bolt preload. 2. Add time-varying loads. Both forces are set up, and they work fine when used alone. After merging, I set it multiple times in loadstep, but it still cannot be solved. Can you help me?

[@Aeroswap]

Thanks! Create a static loadcase for the bolt pretension. Then create the transient loadcase and in the STATSUB (PRELOAD) field, assign the previously created static pretension loadcase. This will include the pretension loads in the transient analysis. I hope this is what you are looking for!

[@cxg5654]

@@Aeroswap This approach doesn't seem to work. This link has the attachment I uploaded, can you help me to answer it?community.altair.com/community?id=community_question&sys_id=047c0b13db23c9d0e8863978f49619b5

[@TheArturvito]

Thanks Aeroswap. all videos are objective and very helpfull. Can you approach the subject of pattern repetition in a topology optimization simulation? thanks!

[@Aeroswap]

Glad you liked the videos! Yes, I am planning a tutorial on pattern repetition in optimization. Thanks for the suggestion though :)

[@gllyprakash412]

For the bolt shank you used Beam (CBeam) element what if we use Bar element (CBar)??

[@Aeroswap]

Yes, you can use CBAR type elements as well. Please check out the differences between bar and beam elements before choosing the suitable one for your analysis!

[@marceloborges7392]

I'm doing a college project and I'm not able to simulate in Optistruct, could you help me?

[@Aeroswap]

Sure! Please write an email with details about the issues you are facing. My email address is given in the 'About' secrion of this channel.

[@marceloborges7392]

Não encontrei seu e-mail

[@NeerajKumar-jc3by]

Sir, I want to create element such like that it should produce no restriction while applying compression while the stiffness should come into effect while applying tension..please help in this regard

[@NeerajKumar-jc3by]

We can create such type of elements in abaquas

[@Aeroswap]

We can use CGAP elements to define this type of motion. CGAP elements are generally used to model cables and ropes.

[@NeerajKumar-jc3by]

@@Aeroswap okay Sir,I will check. I want to create the elements for ligaments in medical science. Thanks

[@NeerajKumar-jc3by]

@@Aeroswap as I tried. It provides the input of friction also. I want stiffness only in tension

[@onkarjalkotkar5647]

sir could you create a Multibody dynamic tutorial on hypermesh Motion View with some theory about this topic, please

[@Aeroswap]

Thanks for the suggestion. I will work on this topic soon!

[@gumuso92]

Why don't you use RBE2 element for the rigid

[@emmanuelvassilakis5630]

You can. RBE2 elements = infinitely stiff elements which introduce additional stiffness in your model. RBE3 = interpolation elements, allowing for a better representation of the stress field around the bolt hole. So it is up to you and what you want to investigate with your model, or in some cases company's modelling standardization policy.

[@Aeroswap]

I agree with Emmanuel. The decision between using RBE2 and RBE3 either depends on the study under consideration or the organization which sets the standards for carrying out the study!

[@ekramdanish9405]

Fabulous

[@Aeroswap]

Thank you!

[@farmaneking570]

GOOD. BUT CRIO FILE IS NOT IN DRIVE

[@NeerajKumar-jc3by]

Sir, 3D bolts are original 3D model of bolts or there is in-built way to create 3D bolts?

[@Aeroswap]

Hi Neeraj, as of now HM does not have built-in tool to create 3D bolts. You have to import it as a CAD only.

[@neerajkumar-rd1yy]

@@Aeroswap okay sir.Thank you.

[@neerajkumar-rd1yy]

@@Aeroswap Sir, can we apply pretension in 3d bolts meshed with tetrahedral elements?

[@Aeroswap]

Yes, we can do that.

[@neerajkumar-rd1yy]

@@Aeroswap when I am trying this on a screw, I am getting error,"Normals on the cutting section of pretension are not consistent"

[@shrikantjaybhaye]

thanks

[@pritilad5894]

Sir this 1D or 3D ?

[@Aeroswap]

Hi Priti, this is 1D bolt. I have already posted a tutorial about 3D bolt pretension. Make sure to check that as well.