topic Re: Viscoelastic material model in Simulation Mechanical Forums (Read-Only)

Viscoelastic material model

RansiDevendra6239 — Tue, 10 Jan 2017 07:29:34 GMT

Dear All,
I am trying to use the viscoelastic material model in a simulation. However, I find that the simulation stops at first step. In this I have used material data from a 2D simulation that works ok. The copy of the model is attached. I would appreciate very much if someone can please advise me how to make the model to work.
Thank you.
Best regards,
Ransi

Re: Viscoelastic material model

shigeaki.k — Wed, 11 Jan 2017 09:28:25 GMT

Hello Ransi,

Have you tried looking at reducing the displacement load and start with smaller deformation i.e. always start with a simpler model.

I would also look at the effect of time step size. Some information can be found at:

http://help.autodesk.com/view/ASMECH/2017/ENU/?guid=GUID-B291DA2F-ABDE-4DEF-9C3D-9CF8C013F8DA

http://help.autodesk.com/view/ASMECH/2017/ENU/?guid=GUID-B60D7999-4BE5-4C48-B85E-E56624E234D5

With Regards,

Shigeaki K.

Re: Viscoelastic material model

RansiDevendra6239 — Wed, 11 Jan 2017 22:41:28 GMT

Hi Shigeaki,

Thank you for the advice. However, I have tried the same material data in other 2D models and I was able got them to work by adjusting the duration time. The simple 3D model I posted, for some reason did not get to the first step even by changing time step size or duration time? I am using V2016 ?? Is there anyone who has used this scenario and had success?

Thank you.

Best regards,

Ransi

Re: Viscoelastic material model

shigeaki.k — Thu, 12 Jan 2017 09:09:14 GMT

Hello Ransi,

I have made a similar model and applied your material, and was able to achieve couple of sub-steps. I am still working on it and will come back to you as soon as I make any progress.

Regards,

Shigeaki K

Re: Viscoelastic material model

shigeaki.k — Fri, 13 Jan 2017 08:56:03 GMT

Hello Ransi,

I had a look at your material properties and it looked like the density, bulk modulus and 1st and 2nd constant were the only parameter values added so I made another Hyperelastic Mooney-Rivlin material with your material data values. The model was then able to run for applied displacement of 0.5" (I have yet to test it for displacement of 1").

I will have a further look what parameter not defined in the viscoelastic model is causing the simulation from not converging. But as you did not seem to have placed values in the other parameters, is viscous behaviour something you are currently looking into?

Regards,

Shigeaki K.

Re: Viscoelastic material model

RansiDevendra6239 — Fri, 13 Jan 2017 09:39:55 GMT

Hi Shigeaki
Yes, I am trying use the viscoelastic material model to simulate rubber components. The model I posted was a simple model with displacement. In this I used viscoelastic material data that was used in a 2D model (Mooney Rivlin). As I mentioned in my last e-mail I also used this material data to model other 2D models and they worked fine. This data does not work with 3D models? I believe the 3D model should work unless the software has some issues?? All 3D models worked with hyperelastic material model but not with viscoelastic material model?
Best regards,
Ransi

Re: Viscoelastic material model

shigeaki.k — Mon, 16 Jan 2017 08:59:43 GMT

Hi Ransi,

thanks for the answer. I wanted to confirm the usage of the material type.

I had a proper look at the parameter settings. Could you try using single core to run the analysis and see if it works for on your side. It seems to work on my side.

Regards,

Shigeaki K.

Re: Viscoelastic material model

RansiDevendra6239 — Mon, 16 Jan 2017 10:14:54 GMT

Hi Shigeaki,

I tried single core and it worked.

Best regards,
Ransi

Re: Viscoelastic material model

shigeaki.k — Tue, 17 Jan 2017 00:18:58 GMT

Hi Ransi,

glad to hear that it worked. I will "accept as solution" the post with regards to the use of the single core, so others know what to do if they encounter a similar situation in the future.

Regards,

Shigeaki K.

Re: Viscoelastic material model

RansiDevendra6239 — Tue, 17 Jan 2017 08:41:38 GMT

Hi Shigeaki,
Thank you. Will this get fixed in a future release?
Best regards,
Ransi

Re: Viscoelastic material model

shigeaki.k — Wed, 18 Jan 2017 02:25:14 GMT

Hi Ransi,

I can't be sure of when but I have informed the team in charge of the issue.

Regards,

Shigeaki K.