Self-heating and dynamic mechanical behavior of silicone rubber composite filled with carbonyl iron particles under cyclic compressive loading

Self-heating and dynamic mechanical behavior of isotropic silicone rubber composite (SRC) filled with micro-sized carbonyl iron particles (CIPs) subjected to cyclic compressive loading have been studied. Effects of pre-strains from 5 to 20%, strain amplitudes from 1 to 5%, and excitation frequencies from 10 to 50 Hz on the self-heating and dynamic mechanical response of the isotropic SRC were investigated. The self-heating temperatures were measured on the surface and at the center of cylindrical SRC specimens. The self-heating temperatures of the isotropic SRC samples showed a fast increase in an initial transient stage and the following isothermal stage. The temperature distribution in the isotropic SRC specimens was non-homogeneous and the temperature decreased from the center to sample edges. The self-heating temperatures of the isotropic SRC increased gradually with raising the strain amplitude and frequency. However, the difference between the internal and surface temperatures was slight for low strain amplitudes and frequencies, while it was significant for high strain amplitudes and frequencies. The temperatures of the isotropic SRC boosted rapidly with increasing the pre-strain to 10% and thereafter gained slightly. Although the isotropic SRC dynamic moduli reduced with the rise of the strain amplitude, they enhanced with increasing the pre-strain and frequency. Besides, the storage modulus of the isotropic SRC varied slightly with time, while the loss modulus reduced markedly especially at the initial period. The decrease in the loss modulus of the isotropic SRC under cyclic compressive loading is attributed to its self-heating temperature rise. A finite element simulation of the heat transfer in the SRC cylinder was conducted. The calculated temperatures in the SRC cylinder were in good agreement with the measured ones at different strain amplitudes and frequencies.