Stable and unstable viscoelastic crack growth: experimental validation of nonlinear theory for rubber

A theory of viscoelastic crack growth that accounts for global and local (crack-tip) viscoelasticity, as well as continuum nonlinearity, is used to analyze stable and unstable crack growth data on carbon black-filled rubber. First, we briefly review relevant results from a recently published linear theory that compares the effect of various models of the failure zone (fracture process zone) on crack growth. Then, it is shown that an extension of this theory to include nonlinearity is in very good agreement with experimental data on crack opening displacement and crack speed for rubber with three different volume fractions of carbon black.