Influence of the temperature on the hyper-elastic mechanical behavior of carbon black filled natural rubbers

• Hyper-elastic response of filled rubbers is investigated at different temperatures.
• Filled rubbers exhibit a complex temperature-dependent mechanical behavior.
• Influence of temperature on the filler-rubber mechanisms is discussed experimentally.
• The notion of the deformation amplification is employed to include filler effect.
• A constitutive model capable to explicitly capture temperature effect is proposed.

This paper investigates the temperature and filler effects on the hyper-elastic behavior of reinforced rubbers. Firstly, mechanical tests are carried out on a series of natural rubbers with different volume fractions of carbon black particles at different temperatures. A non-contact optical technique with high precision of measurement is employed to obtain displacement fields, and the stress-strain responses are consequently achieved. In the studied temperature range, the unfilled rubber exhibits a well known entropy-related behavior, while the filled rubbers behave as a complex temperature-dependent characteristic in addition to enthalpy-related behavior. Test results also show that the filler effects on the hyper-elastic properties of rubber elastomer, such as material stiffness and “S” shaped nonlinear response, are seriously influenced by the increase in temperature. Based on these experimental observations, a thermo-mechanical model is developed to describe the hyper-elastic response of filled rubbers over a wide range of temperatures. In addition, the prediction ability of this proposed constitutive model is verified by comparison with test data issued from the mechanical experiments, which shows that the model is suitable to characterize the large deformation behavior of filled rubbers at different temperatures at a certain degree.