Characterization of the high and low strain rate behavior of a filled, crosslinked elastomer

This investigation characterizes the behavior of filled, cross-linked elastomers used in the construction of golf balls over a broad range of strain rates. Uniaxial compression data, at low rates (using a screw-driven tensile test apparatus) and at high rates (using a Split Hopkinson Pressure Bar) are used to evaluate two models from the literature in order to determine their ability to predict the behavior of the material. Of these, the Bergström-Boyce model for time-dependent finite strain elasticity has been determined to properly model the response of this material over the entire range of strain rates, using only four material constants for moderate strain levels (about 20%).; Case studies were then performed in order to determine the applicability of this model to the range of material compositions (using the same base elastomer) likely to be encountered in golf ball construction. These studies have yielded important results, in that filler content and cross-link density alone completely describe both the low-rate and dynamic response of the material. Moreover, it has been demonstrated that there is a strong dependence of the parameter governing theoretical chain reptation on cross-link density.{09}All of the above comprises a very practical outcome, as it allows for the prediction of performance of golf balls of any given composition.