I try to model the rubber seismic isolator using Ansys. Then compare with isolator from laboratory testing result. In laboratory test, I found that, the damping of the isolator around 12%.
Hi
I do not mean to dishearten your efforts but, rubber is a headache when using linear models or for that matter, most models.
To start, there is the Mulins effect to consider
https://en.wikipedia.org/wiki/Mullins_effect
Then, you have also the fact that rubber is visocelastic, albeit, in a stable part of the WLF function
https://en.wikipedia.org/wiki/Viscoelasticity
https://en.wikipedia.org/wiki/Williams%E2%80%93Landel%E2%80%93Ferry_equation
https://en.wikipedia.org/wiki/Time%E2%80%93temperature_superposition
The above not only affects your model but also how you do your test as well as under which conditions your seismic isolatorwill be used.
Last, beware of the phrase damping as there is a factor 2x difference between critical damping ratio (x2 =) and structural loss factor.
So, to test correctly, you must simulate reasonably correct and you should have a good idea about the ambient temperature as this is the controlling variable as long as the isolator is not overloaded.
On a more constructive note, the best rubber model I have seen (I am no expert on this subject) is the Bergstöm-Boyce model which can be implemented as a user material in Ansys.
https://polymerfem.com/content.php?77-bergstrom-boyce-model
https://www.researchgate.net/publication/225224524_BergstrmBoyce_model_for_nonlinear_finite_rubber_viscoelasticity_theoretical_aspects_and_algorithmic_treatment_for_the_FE_method
Hope this helps. Rubber is unfortunately not easy if you really need to capture its properties.
Sincerely
Claes
Article Bergström-Boyce model for nonlinear finite rubber viscoelast...
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