Viscoelasticity in Ansys

[mailabhi9]

HI All,

I am Abhijit Potdar from India.I am trying to model viscoelasticity using Silicone in ANSYS. I obtained the Experimental data for Silicone from this website.I used the elasticity equations G=E/2(1+nu) and K=E/3(1-2nu) to obtain the shear modulus and bulk modulus.I am trying to used this derived data for defining the viscoelastic material using Curve fitting in ANSYS.
Am i going the right way??? Could Some one please guide me regarding the definition of viscoelastic properties in ansys using the experimental data ???

[Jorgen]

Hello Abhijit,

Your approach sounds right. As you mentioned, I believe that ANSYS has a built-in curve fitting approach to find the viscoelastic properties. However, I will probably require that you give it stress relaxation or creep data.

If you don't have that data, then you can:
(1) generate the needed data through experimentation
(2) look for the data through a literature search (unfortunately I don't have the data that you are looking for)
(3) fit the viscoelasticity model to the tension data that you already have.

- Jorgen

[niranjan_avate]

Curve fitting approach is given in ANSYS. Can some one explain what values of parameters to be used for silcon. which type of element is best suited for beam analysis ?

[Jorgen]

Since there are many different types of Silicone, including Silicone rubber, it is not possible to specify material parameters for your material. Depending on how accurate your predictions need to be, you might need to perform some experiments, or perform a literature search.

- Jorgen

[mailabhi9]

hi jorgen,

i just wanted to ask you that do you have the Mooney-Rivlin material coefficients for the Silicone rubber data you have provided on this site.For the Silicone rubber availble on this site you have modeled the properties using linear viscoelaticity model based on 8-Chain Hyperelasticity and a 3-term Prony series.Could you tell what the material parameters which are mentioned on the graphs..eg alpha1,mu1 etc..

this could greatly help my project.

thanks in advance

[Jorgen]

Unfortunately, I have not yet fitted the Mooney-Rivlin material model to the silicone rubber data.

The material parameters that are listed in the figures have very specific meanings for each model. Which of the four models that is listed on the page are you interested in?

Jorgen

[mailabhi9]

hi jorgen,

i am interrested in the Linvisco(8 chain, 3 term prony series).

regards,
Abhijit

[Jorgen]

Hello Abhijit,

That material model is specified using the following 12 material parameters:

8-chain modulus:
(1) shear modulus
(2) limiting chain stretch
(3) bulk modulus

Prony series term 1:
(4) tau_1
(5) g_shear_1
(6) g_vol_1

Prony series term 2:
(7) tau_2
(8 ) g_shear_2
(9) g_vol_2

Prony series term 3:
(10) tau_3
(11) g_shear_3
(12) g_vol_3

- Jorgen

[mailabhi9]

thanks jorgen for the valuable data. i would be using this data in my simulations. And 1 more question ....whats the youngs modulus and the shore hardness of the silicone rubber for which you have provided the data on the forum????

[Jorgen]

You can extract the Young's modulus from the experimental data. Unfortunately I know what the shore hardness of that material was.

- Jorgen

[foransys]

I study viscoelastik material. but, I think, I didn't defined. can you look at file please? thanks