Modal Analysis using Hypermesh [Optistruct Solver]

[@kenkim2687]

Nicely presented about the importance of modal analysis. To be more specific this method is fixed-free condition to identify the frequency responses based on the applied vibration rage. Typically the ESE results in positive values and we can identify the "potential failure areas" before applying the structural BCs and LCs. When ESE result in negative values then it means your BC is inaccurately defined. I'm sure you already know but there is another method called free-free condition, this is exactly same as fixed-free, only difference is removal of BCs. I used this method to check the element quality and potential numerical errors within the model. You can expect the epsilon values to be nearly 0 as close as possible as there is no fixed BC to respond. The Industrial standard is typically less than 0.001 when meshed accurately. When it is greater then re-meshing needs to be performed around the region. Due to the time restriction, many analysts skip this stage and directly jump into the LCs for quick analysis results. It is okay when you're confident in your modeling techniques. But as we all experience numerical errors happen often and random, and we might save more time in the end by catching these potential issues in the early stages. Always remember.. Garbage in garbage out.

[@Aeroswap]

Wow very useful information Ken! Yes, I know about the free-free run analysis. As far as I know, for a free-free run, the first 6 mode shapes should have negligible deformation patterns and ESE values as all 6 main degrees of freedom are unconstrained. Free-free run can also be used to check connectivity issues in the mesh. I read somewhere that fixed-free run is performed for structural components which will later be used for structural analysis with loads and constraints. On the other hand, free-free run is done for models like ships and aeroplanes where there is no physical constraints during dynamic operation. This is followed by interia relief analysis rather than structural. Please share your thoughts on this. Do correct me if I'm wrong!

[@kenkim2687]

Aeroswap yes thank you for bringing up about the inertia relief. Free free is well used in aerospace industry. And yes typically the first 6 modes (trans/rot dof) are investigated for the checks. Always enjoy your presentations. Keep up with the great works!!

[@benf7223]

Nice Presentation. Kudos to the presenter. Simple and covered all neccesary information.

[@Aeroswap]

Thank you :)

[@gowrishankarm2485]

you are doing a great job! keep it up bro, presentation was clear and understandable. Thank You!

[@Aeroswap]

Thank you :)

[@shrikantjaybhaye]

thanks...you r great, very helpful for me

[@abhishekkarn7591]

Great content to get a quick overview

[@tomasenrique]

These videos are great! Thanks for sharing!

[@saumyaabhupendrabhure2ndpe409]

Very Nicely explained...Thanks

[@Aeroswap]

Glad it was helpful :)

[@komminenipurnachander693]

nice explanation bro keep on moving all the best

[@Aeroswap]

Thank you!

[@jmy3592]

Hi, thanks for the video. Btw, Hypermesh in my PC doesn't have the EIGRL card.. Do you have any idea with this issue? Solver interface is set to Optistrut, correctly. To be more specific, below is the list apppears on the Load collector Card Image dropdown window. '..., DTI, FATDEF, ...' As above, there is no EIGRL card on the list..

[@nisarggandhi7433]

Hi sir, i cannot find eigrl card image from drop down menu can you tell me how to add it

[@Aeroswap]

Hi Nisarg, in newer versions of HyperWorks, EIGRL is not a card image for loadcollector. Instead, you will find this in 'Loadstep Inputs'. Thanks for pointing this out!

[@kumarabhinav4913]

not able to find eigrl card against the card name..please help

[@Aeroswap]

Hey! Try using the search bar (CNTRL + F). It might be available as a loadcollector type if I'm not wrong. They keep switching the card locations with almost every update of the solver. I hope this helps!

[@ninadmhatre6311]

How to provide contacts to bearing in Hyperworks

[@rampawar7983]

Nice Video Sir, It will be help us to modal analysis setup

[@mechdesigns6255]

Excellent explanation

[@NishantJoshi-q4o]

What is significance of setting frequency in modal analysis?

[@EmoVlogs20]

how can input the SolidWorks 3D Design this Software bro ?

[@Animeking2024]

Pretty Good explanation......upload more analysis like dynamic and pseudosound etc

[@Aeroswap]

Thank you!

[@PradeepYadav-119]

superb bhai, well done

[@Aeroswap]

Thank you!

[@sreddy5500]

Great work... Needs tutorial on direct and modal frf

[@Aeroswap]

Thanks! I will work on it 👍🏻

[@timm4552]

great videos, thank you for uploading this!

[@Aeroswap]

Hey Tim! Glad you liked the video.

[@adityakhotte8683]

Really appreciate your work brother!!

[@Aeroswap]

Glad you found this helpful !

[@abhishekpanjiyar8266]

Please provide cad file also.

[@neerajkumar-rd1yy]

Sir,how can we show the deformed and undeformed shape simultaneously in hyperview?

[@Aeroswap]

Hi Neeraj, Use the 'Deformed' panel and check the underformed option. This will enable both shapes to be viewed simultaneously.

[@neerajkumar-rd1yy]

@@Aeroswap thank you Sir

[@yagneshmehta9186]

Preety good work bro... Do also include some really explain good things like modal effective mass and modal fraction for better information.

[@Aeroswap]

Thanks! I will make sure to include these things in another video about modal analysis 👍🏻

[@taonguyenvan3888]

Sir, why do you choose 10 for the number of modes (ND)?

[@PranaovChellian]

I'm planning to topology optimisation on a component. I already know that static structural analysis is integral for this process. If I want to do modal analysis, can I incorporate it into the same process, and will it impact the topology optimisation at all? Any help on this would be much appreciated. Thank you.

[@diwakarthik]

Thanks a million Brother :)

[@vivekkrgowda240]

Hi pls tell me how to remove error 1485 and 1000 when we run file.

[@Aeroswap]

I cannot tell a solution just by reading the error number. Please elaborate more on what the error message says so that I can suggest any corrections if possible.

[@vivekkrgowda240]

@@Aeroswap pls make video on how to convert ls Dyna file to optistruct for modal analysis

[@Aeroswap]

You can do modal analysis in LS Dyna. No need to export to Optistruct.

[@vivekkrgowda240]

@@Aeroswap pls make video on these

[@Aeroswap]

I will work on it. Thanks for the suggestion.

[@fabrizioantermite4926]

Hi, and thank you for the video. Can you show how to perform modal analysis on a model with non-linearities (contacts, non linear elements, etc.)? Thank you in advance.

[@abhishekborde1219]

How did u decide number of modes ? and what did u mean by intire spectrum

[@Aeroswap]

As there are 6 main degrees of freedom (3 translational and 3 rotational) the first 6 modes of vibration correspond to each of these DOFs. The 7th and 8th modes are bending and twisting modes. (These are most important) Further modes represent random deformation patterns. Therefore, according to industry standards a minimum of 6 modes is calculated. Usually the number is rounded up to 10. In a bounded frequency range there are a specific number of discrete values ( for example 0Hz - 1000Hz). By entire spectrum, I mean from 0Hz to infinity. Hope this clears your doubts.

[@abhishekborde1219]

Thank u

[@girishnaganagoudar3057]

Sir nice vedio model analysis. Sir plz prepare more vedio on dynamic analysis

[@Aeroswap]

Yes, I am always working on creating new content. Keep the notification bell turned on to get latest video updates instantly 👍🏻

[@eduserenza]

Great vídeo

[@Aeroswap]

Thanks for watching :)

[@AbhishekSharma-hh6kj]

Great effort. I have a question that which meshing type is more preferred in this case, a Tetra Meshing or a Hexa Meshing? Please also specify the reason. Waiting for your response..........

[@Aeroswap]

Hello Abhishek, Tetramesh can be done more easily and does not take time but the analysis will take longer time to solve (as number of elements generated are more). Hexamesh takes time as some geometry cleanup and mapping is required but the analysis will have lesser solving time (as number of elements is usually less). Regardless of the above comment (based on solving time), a good quality tetramesh or hexamesh will provide good results. Feel free to go for whichever type you want to. Just make sure that the element quality is good!

[@AbhishekSharma-hh6kj]

Ok but in case of structural analysis, hexa (3D) or quad (2D) meshing is more preferred as they provide more result accuracy. Am I correct?

[@Aeroswap]

Yes, but this is not always correct. A good quality tetramesh can also provide similar results as hexamesh.

[@AbhishekSharma-hh6kj]

Ok and thank you very much for your support.

[@AbhishekSharma-hh6kj]

Could you please give me your email? As you told me before, I searched for it under ABOUT section but didn't find there.

[@sumendukumar8050]

Hi, thank you for this tutorial, can we do modal analysis including rotor dynamic analysis for Rotor ?

[@gllyprakash412]

Hi, You have used first order tetra elements for the analysis. But usually we use second order tetras right? Because first order will be inaccurate results. May I know the reason.

[@mohamedriyazpeermohamed1879]

Is the normal mode analysis and modal analysis are same ?

[@Aeroswap]

Yes, it is the same.

[@kiranneelakanthmath9429]

Thank you so much

[@billifer654]

Love your videos! ANy plans on doing videos on Hyperworks 2020 since it is a newer interface?

[@Aeroswap]

Hey Billy ! Hyperworks 2020 is new; not having a user-base as large as traditional Hypermesh. But I will surely look into making tutorials about that! PS : Glad you found my videos helpful.

[@matteoorzalesi7590]

Hi sir, great video and very clear explanation. How could i find the oscillating mass and the oscillating period for each vibrating mode? Thank you

[@ansariyaseer4651]

Thanks, Sir Nice and clear explanation, when I performed this analysis it showing me this error "Incorrect data in field # 3. Field 'PID' of CTETRA bulk data." What should I do sir?

[@Aeroswap]

Check if the material and property is assigned to the component.

[@ansariyaseer4651]

@@Aeroswap thanks, I am getting results.

[@premkumarnaikar1877]

Sir make a video of gear analysis

[@Aeroswap]

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

[@amshavarthanjosh1341]

Very useful

[@lakshman302]

1501 fatal error occurred

[@Buzz_Mustermann]

Oh god, I like Indians

[@danilseyfullah6881]

thank you for a job and good explanation

[@sudmudmud357]

Awesome 😊