Standards for testing elastomeric materials

[Waqas Khan]

Hi Mr. Jorgen,

Its been quite some time since I logged into PolymerFEM. But its the only site that comes to mind when I have difficulties with Polymers.

This time, I just wanted to ask you if you can provide me with the standards for testing of the following elastomers.

1. Pure rubber
2. Neoprene
3. Silicone rubber
4. Vitton

Like what kind of a specimen do I need and what experiments should I carry out for modelling complete viscoelastic behavior of the elastomers?

Thank you,

Regards,

Waqas Khan

[Jorgen]

Good to hear from you again.

You are asking a good question. As far as I know there are now well established standards that are sufficient for determining the complete viscoelastic response of elastomers. I usually perform the following tests:

Uniaxial tension followed by unloading at at least 3 different strain rates
Uniaxial compression followed by unloading at at least 3 different strain rates
Perhaps also one or more stress relaxation tests
In some cases I then perform additional shear or biaxial tests

I then repeat these experiments at various temperatures if I am interested in determining the temperature response of the material.

I typically use the specimen dimensions that are specified in the ASTM standards for compression and tension experiments of polymers (D0638, D0575).

-Jorgen

[Waqas Khan]

Thank you for your response.

I have seen some of the experimental data that you have posted. The standards ASTM D638 and ASTM D575 - Are they valid for all elastomers that I listed above?

Thank you once again.

Waqas

[Jorgen]

Yes those standards are valid. Note, however, that I only use the standards to obtain suitable specimen shapes and dimensions. I usually perform the testing slightly differently than what is specified in the standards.

-Jorgen

[Waqas Khan]

And why is that so?????

[Jorgen]

The ASTM standards that I mentioned are not "optimized" for material model calibration. Two problems with the standards are (if I remember right):
1) Only one strain rate is used (better to test at multiple strain rates)
2) Only monotonic loading is used (better to record the response during both the loading and unloading)

-Jorgen

[Squid81]

Is not possible to use ASTM D 412 - 06a ?
Is it good for the determination of Young's modulus?

Thanks a lot.

Regards.

[Jorgen]

If I remember right, ASTM D412 is to rubbers. You can determine Young's modulus from any uniaxial tension test, perhaps including D412.

-Jorgen