Hypermesh Nonlinear Contact Analysis [Optistruct Tutorial]

[@AdarshKontikal]

If anyone is having trouble locating contact surfaces in newer versions of Hypermesh just right click - create - select set segments. (the contact surface option is moved to this option in newer versions )

[@Aeroswap]

Thanks for pointing this out Adarsh!

[@AndrewBeatcast]

Thank you very much!

[@dafabi6718]

I have been loosing sleep over my Bachelor's thesis. Your Videos are a true lifesaver! I love you man

[@Aeroswap]

Good luck!

[@satwikaaero1886]

very super explanation which was clear and easily understood by the peoples, thanks a lot for clear explanation 👍

[@Aeroswap]

Thank you for watching! Dont forget to subscribe for more videos 👍🏻

[@praveeningavle7274]

Nice work with proper explanation... excited to watch new analysis part..

[@Aeroswap]

Thanks Praveen

[@tomasenrique]

Such great videos, man! Thanks!

[@emmanuelvassilakis5630]

Very nice. My kind recommendation is to spend some time explaining the property options in the definition of group contact. Keep up the good work!

[@Aeroswap]

Thanks for the suggestion! I will try to get more into the details from next time 👍🏻

[@furkanyalcn7697]

Dear friend, I am watching your tutorials for a few days and you are doing a great job, thank you for your efforts! In addition, I have same concerns with Emmanuel. I performed the same analysis succesfully but I don't have so much information about "PCONT parameters and Contact parameters". Could you please explain these parameters also? Thanks in advance, greetings from Turkey!

[@Aeroswap]

I agree, I will probably create a separate video explaining each setting in the contact parameters. It is surely not as easy at it looks!

[@emmanuelvassilakis5630]

@@furkanyalcn7697 PCONT parameters, or contact parameters in general are something that one must devote substantial amount of time in order to understand and implement correctly in an analysis. What you enter in the contact card might well mean the difference between a successful analysis and a failed one. If Swapnil has the time he can prepare a presentation, however it is a topic that cannot be covered in a single tutorial; it requires deep knowledge of contact modeling techniques and experience with that type of analyses. Regards, Emmanuel

[@furkanyalcn7697]

Thank you both. I agree with you Emmanuel, so that's what I am trying to learn especially :)

[@tomasenrique]

Great video!

[@prithvirajkokkula5794]

Firstly, Great job . Absolutely love your videos. keep doing more . Quick Question . As Non-linear material properties were not assigned to the components, How accurate are the stress values ? How will we know if the plate is breaking or if it is above yield ?

[@Aeroswap]

Thank you! Yes, nonlinear material was not assigned here as I have covered geometric and material nonlinearity in a separate video. The main focus of this video was boundary nonlinearity through contacts. To get accurate results, material nonlinearity has to be set in this case. As this was out of the scope for this video I have not done it. You can try and check the results!

[@Mad-zx3me]

Thank you. Great explanation 👍

[@Aeroswap]

Glad it helped :)

[@muhammadaliabid5793]

Wonderful explanation! Much needed tutorial. A request: Could you please make a video explaining usage of spring elements please. I guess we can use spring elements like rigids elements depending on the case! Probably we can define the spring constant 'k' in that case.. Sorry for rough explanation though but would be appreciated if you tutorial on that too.

[@Aeroswap]

Thanks! Yes, you are right. Spring elements can act as rigid elements if the stiffness 'k' value is extremely high. I will make a tutorial on this topic soon!

[@muhammadaliabid5793]

Will be waiting for it sir😀 Thanks a lot

[@babatoli]

Great work 👍

[@Aeroswap]

Thank you!

[@hariprasad-xh3dp]

Great work

[@Aeroswap]

Thank you!

[@kenkim2687]

Great example of the nonlinear contact analysis. I like how you pointed out the importance of mating contact surfaces along with the element normal directions. I'd like to ask you a personal favor to complete this nonlinear chapter. Could you do another tutorial for a 3D multi body nonlinear with material nonlinear and contacts defined? I often run into errors during/after the solver, I'd like to see if I do anything incorrect during the preprocess stage.

[@Aeroswap]

Hey Ken, do you mean something like a gear pair in mesh ? If you have a particular model in mind, let me know. Currently, I am working on a 3D model with nonlinearity. It takes a very long time to solve even with good hardware. This will be interesting! I will start working on this right away 👍🏻

[@kenkim2687]

@@Aeroswap Glad to hear you're already working on a 3D nonlinear. A gear pair can be a good example, but yeah what I meant was just general 2 or 3 components where you can assign contact surfaces. But whatever you're working on now would be very helpful! Thank you for your hard works.

[@Aeroswap]

Thanks Ken! I'll try to finish up the video as soon as I can.

[@abhilashpatil9842]

why u have not used SPCD type for enforced displacement?

[@Aeroswap]

Hello Abhilash, there are multiple methods to apply enforced displacement. We can use any method we are comfortable with. Feel free to use SPCD. You will get similar results like my method.

[@abhilashpatil9842]

@@Aeroswap thanks for reply, u r doing great work. keep it up

[@adelinewar3222]

Thank you for this tutorial. It was very helpful for my research work. Can you please put a video on meshing as well. And what is EXPERTNL?

[@Aeroswap]

Hello Adeline, I'm glad the tutorial helped you with your work. I have already posted some videos about 2D, 3D meshing using Hypermesh. Please check the 'Mesh Generation' playlist on the channel. EXPERTNL is setting which helps to achieve better convergence for complex nonlinear problems. EXERTNL automatically changes some solver parameters according to the problem under consideration to provide a better solution. I hope this answers your question!

[@akcalixto]

Great tutorial. However, I cannot see the option "Contact Surface" to create a collector. My HyperMesh 2020.1 has only the option "Contact". How can I create the contact surface?

[@Aeroswap]

Yes, they have made several changes in the newer versions of Hypermesh. Try using the Contact browser. It can be enabled from the View dropdown in Tools bar. I guess there is an option in the contact browser to define the contact surfaces manually. Thanks for pointing this out. I will soon make an updated video about this!

[@ezeddinekaroui8690]

@@Aeroswap Hi Guys, I faced the same problem as for @akcalixto that I don't find surface contact option as I use Hypermesh 2020 and after a reaserch I found it under ( create-->Set segment and change the card image to surf ;) it works great)

[@Aeroswap]

Looks like I should make another contact analysis video with the newer version of Hypermesh. Will work on it soon!

[@yesvanthr4878]

Can you please explain about large displacement card used for non linear analysis

[@Aeroswap]

Hi Yesvanth, Please watch my first tutorial about nonlinear analysis. In that, I have demonstrated large displacement as a type of geometric nonlinearity.

[@saaarjit]

Amazing video to get introduced with contact analysis. Thanks. Also, I have a doubt, so you assigned thickness 1mm to the support, plate and roller. This results in the elements from support (if viewed in 2D detailed element representation) crossing into the plate and not just ending at the surface. I'm not sure if it has to be like this or the elements of support and roller should only touch the outer surface of the 2d elements of plate.

[@Aeroswap]

Thanks Sarjit! I am glad you liked the video :) Good question! If you enable the GPAD option in the contact settings, thickness will be taken into account. Please try that option to avoid crossing of elements in detailed representation. I hope this helps!

[@saaarjit]

@@Aeroswap Thank you for your reply and the info.

[@ekramdanish7790]

Sir plz, tell how to reflect or translate contact?

[@SivaKumar-zy8pr]

Great work bro. But a small suggestion while you are adding few parameters(for ex nlout here ) could you explain what do those mean ?? It would be very helpful . Thank you

[@Aeroswap]

Sure, I will explain more about such settings in all upcoming videos.Thanks for pointing this out!

[@SivaKumar-zy8pr]

Iam new to optistruct . So i could not grab the few terms like expert nl and their function

[@Aeroswap]

Got it. It is difficult to understand for a beginner. I will try to explain in simple terms 👍🏻

[@ezeddinekaroui8690]

Hi swapnil Great job as usual :D I want to go forward and plot Force vs Displacement curve in hypergraph how I could do it ? or what you recommand to follow for better understanding for plotting ?

[@Aeroswap]

Yes, that can be done. I don't think I will be able to explain the process in a text message! It is explained in detail on Altair forum. If you still face an issue after referring the forum, feel free to contact me via email :)

[@jaericx3192]

Great tutorial. Do the contacts have to "touch" in the cad model? I want to optimize a my composite layers so my thickness might change over the iterations. Making a new cad model every time does not seam like the correct way. Plus i dont know if the mid surface aproach would work for thicker materials

[@Aeroswap]

No not at all. You dont need to create a new CAD model for every analysis! As the gap between the components is small, the components will move closer due to applied boundary conditions and then the contact will get activated to avoid further movement. As for midsurface, if you want the solver to define the contact with added thickness, switch the GPAD setting to THICK. This will include the thickness of all shell components during contact operation. Hope this answers your doubts :)

[@jaericx3192]

@@Aeroswap Thank you for your fast response. That helped me a lot. Keep up the nice work 👍

[@sahibdantya9891]

Why are we using NLPARAM Card? And NLPARAM(LGDISP)

[@Aeroswap]

NLPARM card is essential to run any nonlinear analysis in Optistruct. Without this card, the nonlinear analysis will give an error and no results will be obtained. This card specifies the convergence and load increment parameters for nonlinear analysis. For more information about NLPARM and LGDISP, please refer the Optistruct user manual. Feel free to reach out if you face any difficulties. My contact details are provided in the 'About' section of this channel.

[@sahibdantya9891]

Why are we selecting finite sliding in our model. why not small sliding. And what is the difference between two. When do we use small or finite sliding?

[@Aeroswap]

Hello Sahib, Good question. If you observe the contact settings, there are 3 types of formulations - small sliding, finite sliding and continuous sliding. Small sliring is used when the relative moyion between parts is negligible (eg. Bolt-nut assembly). Finite sliding is used when there is significant relative motion but the region of contact remains constant (eg. 3 point bending as shown in this tutorial). Continuous sliding is used when there is large relative motion and the contact surface has to be updated after certain intervals of time (pinion-gear in motion). I hope this clears your doubt !

[@ezeddinekaroui8690]

Hi all I want you to help me by giving information, Actually I'm facing a confusion about RBE3, I want to know if RBE3 distributes the load (Force,Displacement,..) to the connected nodes equally or it divide the load for all connected nodes ? for example: RBE3 connected to 4 nodes: once we apply 10 (Newton or mimmiliters ) on the RBE3, Is each node of the 4 independent nodes has 2.5 or has 10 like the RBE3? Thank you infinitely.

[@Aeroswap]

I received your email regarding this same topic and I have replied to it. Please check :)

[@ChanghoKim-y7l]

can you tell me dof 2 = 20 ( at the rigid part) mean?

[@jaysoni5717]

I am facing difficulty in optistruct. First of all I am not finding the optistruct option in 'analysis' and when i click solver cmd opens and 'The system cannot find the path specified.' pops up.

[@ekramdanish7790]

In optistruct, Master And slave, in 2021.2 hypermesh

[@mohamedriyazpeermohamed1879]

Can’t we do this using student version? Once I try to run the analysis i am getting no available license in .out file

[@Aeroswap]

You can do this in student version. Just make sure that the license path is properly configured as stated in the student version installation guide.

[@pali_palitrinhvan9919]

hi you, i have a question related in the single surface Patten1 Card image: contact Type:slide Ssid : part a and part B Msid: part a and part B Morient: norm Discret:S2S Trach:Consli Patten2 Card image: contact Type:slide Ssid : part a and part B Msid: part a and part Morient: norm Discret:S2S Trach:Finite so the rusult is penetration please help me how to right setup?

[@ArunKumarGLannu]

Hi, i have an error saying "MORIENT should not be OPENGAP or OVERLAP for finite sliding CONTACT 1" . am using 2017 version

[@Aeroswap]

Try switching contact type from 'Finite' to 'Consli'.

[@ArunKumarGLannu]

@@Aeroswap I tried, but I see the same error

[@Aeroswap]

Did you try changing the MORIENT option to different setting. As mentioned in the error message, try not to use OPENGAP or OVERLAP options.

[@ArunKumarGLannu]

@@Aeroswap Its running for MORIENT = NORM/REVNORM, TRACK = CONSLI. Thank you :)

[@Aeroswap]

Good to know!

[@adelinewar3222]

Can you tell me how to get interface stresses in hyperworks?

[@RehanAhmed-vv9rg]

hello, in my model there is a minute gap and no connection of contact elements. its showing error as *** ERROR 14: Missing element #490502 referenced by SURF # 1.

[@Aeroswap]

This error is not related to the gap. In fact, the gap will not give any error. It is okay to have such gaps in the model. Please check your contact surfaces. Make sure that they are assigned elements with correct normal directions.

[@RehanAhmed-vv9rg]

@@Aeroswap hello, i have checked and saw that all contacts are normal to each other. can you please share me your email so that i can send you the photo? it'll be helpful for me

[@Aeroswap]

My email address is provided in the 'About' section of this channel.

[@RehanAhmed-vv9rg]

@@Aeroswap hello sir, good morning. I have followed your steps and sir my issues are resolved.a big thanks from my side and I appreciate your time and information which you have provided to me.there was an issue of CTRA4 elements and coinciding of plates in my model.after i resolved it I'm able to solve it again. I got the results and other information.keep posting your hypermesh videos and i do recommend in my university to follow up your channel for videos. thanks and regards rehan

[@Aeroswap]

Hey Rehan, Good to know you were able to perform the analysis successfully. Feel free to reach out anytime again in the future :)

[@พีรพัฒน์กิตติศักดิ์ไพรัช]

Do you have 3 point bending Material composite ?

[@Aeroswap]

No, 3 point bending with composites has not been covered in any tutorial on this channel yet. Thanks for the suggestion though. I will work on this topic soon!

[@พีรพัฒน์กิตติศักดิ์ไพรัช]

@@Aeroswap Thankyou

[@prasadchandrakantghadashi4283]

Nice explanation. But, I am facing error #4965 ( Maximum number of time increment cutbacks reached, analysis aborted) while analysis. Is it because l have applied displacement of 140mm which is necessary for my simulation?

[@Aeroswap]

Try this. Create a new loadcollector with card image 'NLADAPT'. In that, set NCUTS value to a high number (for example 100). Then run the analysis again and see how it goes.

[@prasadchandrakantghadashi4283]

@@Aeroswap Thank you for your prompt reply 🙏..

[@prasadchandrakantghadashi4283]

@@Aeroswap Hello l need your help for three point bending test on our beam. Can we have discussion on e mail?

[@Aeroswap]

Sure, reach me via email for better communication.

[@prasadchandrakantghadashi4283]

@@Aeroswap How can we create different graphs like force Vs time and force Vs displacement, etc.

[@shashankabhat2453]

@aeroswap I am getting error for same method