How to set up materially nonlinear analysis in Femap

[@mateuszfrydrycki4935]

Great video! Thank you :)

[@Enterfea]

I'm glad that you like it Mate :)

[@PyleHD]

Thanks for the video. I am using nonlinear PU rubber as my material and I've assigned a stress strain function to it. When I try to do the analysis i get FATAL ERROR 9002 and 316. Can you please help, I'm new to this

[@Enterfea]

Hey Prisha! I won't help you with rubbers as I don't usually use them, but their material models are pretty complex as far as I know. It may be a difficult field to start in... I'm not 100% sure, but the stress-strain curve will most likely be insufficient to fully describe rubber behavior - maybe this is why you get error messages?

[@andrenedaei965]

Hello Lukasz, Firstly, thank you for a very good video. I have done some analysis with material nonlinearity (Nonlinear and engineering SvS curve for plastic) without Arc-length method and found your video very interesting as you use the Arc-length. However, I had problem by converging after increment 25 and the analysis simply stop. I tried one case with bilinear in order to if it can follow the curve and it failed with the same value. Any idea why the load does not reach 95% ish as yours in video? BR André Nedaei

[@Enterfea]

Hey Andre! This is a pretty difficult question to answer, as I don't know what you have done exactly. Clearly, if you would do the same things as I did in the video... you would (well... should...) get the same outcome. So I assume you did something differently. But to give my opinion I would have to look into this, as it is, I simply don't even know where to search for it...

[@Monika-nt2be]

Hi, I'm trying to run a nonlinear steel material model. I thought that when you choose plastic material you have to specify a strain-stress curve?

[@Enterfea]

Hi, Monika, It took me a while to write you back, as I rarely look on to comments under my youtube videos - it is much more efficient to ask at my blog: www.enterfea.com :) As to the question at hand, no you do not need to define a strain-stress curve. Of course you might, inserting additional data but what the shown method does is the simplest way (and I will write something about the more demanding ones later on). What happen if you enter things as I did is that femap generates input file for nastran with keyword MATS1 with following parameters: TID = blank (this would reference the strain-stress curve you mentioned) TYPE = PLASTIC H = blank (this defines the slope of the hardening) YF = 1 which means von Misses yield criterion (it's a default and I simply didn't change it) HR = 1 which leads to Isotropic hardening rule (also a default kinematic and combined are also available) LIMIT1 = 2.35e8 - initial yield point LIMIT2 = blank This leads to situation where both TID and H are blank, which in turns is interpreted as perfectly plastic material. You can read more about this all in NX Nastran quick reference guide (It has over 2000 pages!) what you are searching there is Bulk entry MATS1 (in my version, that would be page 15-62). Also you may read about Bulk entry MAT1 - this may come in handy :) If you have any more questions (or do not feel like reading all that!) you can simply write me an email at: [e-mail] (and it can obviously be in Polish then :) ) I hope that helps :)

[@toshibamaster2210]

Можно пример нелинейной модели стали в виде отдельной библиотеки?

[@Enterfea]

Hey... I'm afraid I don't read that language. Google translate tells me that it's something about nonlinear material and a library... but I can't understand what the question is about I'm afraid :(

[@caulacbophanmem1159]

Do you have a femap installation guide video?

[@Enterfea]

Hey! Sadly I don't. I just re-installed Femap and I need to set it up properly, so when I will have time I will do a video about that. ut the installation itself... not really. I think you can easily contact your Vendor - they will be more than happy to help you out I think :) Have a great day! Ł

[@NTC]

How much is Femap with Nastran?

[@Enterfea]

Hey! This strongly depends on the possibilities of the solver. Femap like a lot of other soft has different modules you can buy "separately". I have no idea how high is the catalog price for the "basic module" - I would guess it's around 8-12k$ but don't quote me on that. You can easily contact your local reseller - they will be more than happy to help you out :) All the best Ł