# Research

## Constitutive Models for Rubbers

We study the emotions of materials. How does a material respond when subjected to an excitation? The response can depend on the history of excitation. On the other hand, the excitation can be stress or strain or even a change of thermodynamic temperature. Perhaps, under such excitations, the microstructure of the material deforms or undergoes though a metamorphosis process. We attempt to study the phenomena that take place within the finite domain of microstructure.

Material behavior of rubber seldom follows the classical elasticity theories. It is sensitive to rate of excitation and history. We attempt to predict the short term and long term behavior of rubbers under large deformation, high strain rate and consider geometric and material nonlinearities. What do you think about the other case, when the deformation is small, strain rate is small or the behaviors are linear? We attempt to write equations that are meant to express all such emotions of rubber. Perhaps these are the generalizations, away from the classical theories and the one can try to describe the simpler cases through simplifications of all such derivations. We consult the theories of continuum mechanics, thermodynamics, thermophysics and a bit chemistry as well. Our domain of consideration is a bit vast and wide.

The outcomes from such research do have applications in different field of engineering. In civil engineering, it is important to design the base isolation bearings for earthquake protection of bridges and buildings, traditional bridge bearings and tunnel linings. In the semiconductor industry, we need to design the seals and gaskets. These may be quite expensive as along as the adopted production technology is expensive. In aerospace and automotive industry, vibroacoustics issues need to be addressed adequately. In biomedical engineering, how do you think about the advantages of a shape memory polymer stent for treating the coronary heart disease? The constitutive equations working behind are the key to offer you a better performance.

##### Featured Papers:

Amin, A. F. M. S., Bhuiyan, A. R., Hossain, T., & Okui, Y. (2014) | Razzaq, M. K., Okui, Y., Bhuiyan, A. R., Amin, A., Mitamura, H., & Imai, T., (2012) | Amin, A.F.M.S., Lion, A., Hofer, P., (2010) | Amin, A.F.M.S., Lion, A., Sekita, S., Okui, Y., (2006a) | Amin, A.F.M.S., Wiraguna, S.I., Bhuiyan, A.R., Okui, Y. (2006b) | Amin, A.F.M.S., Alam, M.S., Okui, Y. (2003) | Amin, A.F.M.S., Alam, M.S. and Okui, Y. (2002)