Crack propagation at the interface between viscoelastic and elastic materials

Crack propagation in viscoelastic materials has been understood with the use of Barenblatt cohesive models by many authors since 1970’s. In polymers and metal creep, it is customary to assume that relaxed modulus zero, so we have typically a crack speed which depends on some power stress intensity factor. Generally, when there finite modulus, shown “apparent” toughness semi-infinite increases between value at very low speeds threshold w0, fast fracture w∞, enhancement factor infinite systems (where classical singular mechanics field dominates) simply corresponds ratio instantaneous elastic moduli. Here, apply model for case bimaterial interface an material, assuming remains interface, neglect details singularity. For Maxwell material propagates only viscosity, fourth factor, not moduli either material. Schapery type law no relaxation are more general results. arbitrary nonzero show maximum “effective” will be reduced respect homogeneous