Steady state crack growth in viscoelastic solids: A comparative study

We compare the predictions of different theories on the steady state growth of a Mode I crack in linear viscoelastic solids. The theories studied in this work include those by Knauss, Schapery, Persson and Brener. The comparisons focus on the fractional dissipation rate and the relationship between crack growth velocity and fracture energy. Analytical solutions are carried out using realistic constitutive models such as the Generalized Maxwell Solid (GMS) and the Power Law Solid (PLS). These theories are tested against two different sets of experimental data reported in the literature. We also present new results such as the strain field directly ahead of the crack tip, the residual strain on the crack surfaces and the crack opening displacement (COD). We use the expressions for COD to study the shape and size of the “viscoelastic trumpet” proposed by de Gennes. Using a new approach, we study the shape and size of the viscoelastic dissipation zone around the crack tip and discuss its dependence on the crack growth velocity.