DO WE NEED VERY STIFF FILLERS?

PERFORMANCE EVALUATION OF HYPERELASTIC MODELS FOR CARBON-BLACK–FILLED SBR VULCANIZATES

The performance of four recently developed hyperelastic material models (HM models) was evaluated by using stress–stretch relationships of filled styrene butadiene rubber vulcanizates with different contents of carbon black (CB) tested under uniaxial tension (UT), pure shear (PS), and equi-biaxial tensile (BT) conditions. The stress–stretch relationships for the PS and BT tests were obtained with a specially designed specimen having higher accuracy than those obtained with an ordinary specimen. The performances of the HM models were compared via the following three evaluations: (1) ability to reproduce the UT, PS, and BT tests; (2) ability to predict the PS and BT test results with material constants identified from the UT test; and (3) correlation between the identified material constants and CB contents. The evaluations based on a combination of the stress–stretch relationships with high accuracy and four recently developed HM models revealed that the HM model activates only the I1 term, which is the first invariant of the right Cauchy–Green tensor, exhibiting good reproducibility and predictability.