Which Element type to take for electroactive polymers??

[sandeep]

Dear members,

I am new to this group and this is my first message.
I am doing analysis on a electroactive polymer. My aim is to built artificial muscle fibres made of electroactive polymers and do analysis on that.

The Muscle structure consists of several fibers together like a Braid .I modelled one such fibre in pro/engineer wildfire 2 and exported it as an IGES file to ANSYS 9.0. I am not able to understand which element type to take for these EAP(electro active polymers). I read the tutorials of ansys. In that it is given that " hyperelastic element " is generally taken for polymers.

I tried using that but i am not able to get the deformation that i want.In my case youngs modulus is between 1 to 10GPa and i dont know how much possions ratio should i use?

Electroactive polymer is a polymer which deflects according to the electric potential applied to it. so my question is :

1. Which element type to take for these EAP materials.
2. How much possions ratio can i take .
3. I took the material model as linear, isotropic. should i try for nonlinear analysis ??

so can any body help me out in this, i would be thankful to you if you do so.

thanks in advance
Regards
sandeep

[Jorgen]

Welcome to the PolymerFEM community!

I am not quite up to speed on ANSYS, but here are my commnents:

:arrow: The muscle fibers can likely be represented using a hyperelastic material model. You might want to use an anisotropic hyperelastic representation.

:arrow: My guess is that the Poisson's ratio is slightly less than 0.5.

- Jorgen

[sandeep]

Mr. Jorgen_Bergstrom,

Thanx for the reply u gave me. I have one question regarding Ogden model material constants. The material used is an electroactive polymer and i am doing Non linear analysis since these EAP undergo large deformation .

I am using the one parameter ogden model because of its accuracy. There are 3 hyperelastic material constants that i should use while doing the analysis and those are :

1. Shear Modulus(Cj)
2. Bj(Material constant)
3. Material incompressibility factor(d)

Bulk modulus(K)=2/d

My doubt is how can i get the values of the 2 material constants for electroactive polymers (i.e Cj and Bj). The notations may differ from person to person. While doing the analysis in ANSYS it is asking the values of these 3 which i mentioned above.

I can find the compressibilty factor but i am not sure of the other 2 material constants. I read some papers which say the results for a particualr material is very sensitive on what values we give for these 2 material constants.

So please help me out . I will wait for your reply
Thanks in advance

Regards
Sandeep

[Jorgen]

Do you have any experimental data for the material? If so, you can find the last two material parameters using a trial-and-error approach until you get a good fit of the experimental data. If you want to be more sophisticated you can also apply a non-linear minimization approach to automate the selection of the material parameters.

- Jorgen

[lorenzo]

Hello,

I have the same problem, I am trying to model a DEA with the Ansys software.

Have you found a way of doing it? A way that matches the experimental results?

Have you found a way of coupling voltage-deformation?

To anyone who works on the subject:

Is there an easy way of introducing experimental results of a DEA material into Ansys and to be able to simulate the coupling between Voltage applied/Deformation?

Thanks a lot for any advice in the subject!

Regards

[murdoc82]

Hello everyone.

I was searching online for methods of modelling electroactive polymer or 'artificial muscles' as they say using ANSYS when I stumbled upon this thread. Like you guys I am trying to do the same thing. I have tried to model the electroactive polymer using ABAQUS before but to no success. The reason being is because I think ABAQUS does not possess the Maxwell stress load required for this type of analysis. (I might be wrong...this is just my personal opinion) I have since then moved over to ANSYS as from some journals it seems to me that ANSYS can do electric field analysis. However the problem with all this software be it either ABAQUS or ANSYS is that no one seems to really how to use or utilize it. Everyone is just learning by using manuals, tutorials, or by asking each other. I have better luck with ABAQUS because it is more popular software so got more people around to ask. But it is different case with ANSYS, especially since most people are more into structural analysis when this analysis is more towards electric field analysis.

Anyway, will let you guys know if I got any success with ANSYS. And if any of you guys do have some success, please share it so that everyone can benefit from it.

[jxj]

Totally agree! Is there anyone know how to couple electric field to the polymer?

[Jorgen]

Is a multiphysics software, like COMSOL, a better choice in your case?

-Jorgen