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 Bergstrom, Ph.D.