Abstract: To explore the effect of carbon black on the mechanical behavior of rubber material, 9 kinds of rubbers filled with different volume fraction of carbon black are studied by quasi-static uniaxial tensile test, and the material constants of Mooney rubber are fitted through the least squares methods, then three-dimensional numerical models containing multi-sphere particles randomly distributed are built to simulate the mechanical behavior of carbon black filled rubber composite. The research shows that the stiffness of the rubber composite is increased considerably with the introduction of carbon black filler particles, and the greater the carbon black filler content, the higher the initial modulus of the rubber composite, the greater the strain energy density at the same deformation condition, and the more obvious the stress relaxation phenomenon. With 7 and 15 percent carbon black filler content, the results of the predictions on the stress-strain behavior of the rubber composite made with the microscopic numerical models are consistent well with the macroscopic test curves. With 25 percent carbon black filler content, the results of the predictions with the microscopic numerical models are slightly below the macroscopic test curve. It demonstrates that the predictions on the mechanical behavior of carbon black filled rubber composite made by the three-dimensional numerical model containing multi-sphere particles randomly distributed are in good agreement with the experimental results, which confirms the rationality and adaptability of the proposed model, and these researches provide the basic and scientific information for further research.

Key words: Carbon black, Micromechanics, Random sequential adsorption, Representative volume element, Rubber