FRAGMENTATION OF VISCOELASTIC SURFACE-LAYERS

Starting from a one-dimensional model, we investigate the influence of viscoelasticity on the fragmentation of a surface layer, wich covers a bulk substrate. The layer is modelled as a chain of breakable spring s, which is coupled to the substrate via Kelvin-Voigt elements. Lettin g the substrate expand, we study the dependence of the fracture patter ns on the strain rate. For high strain rates the initial stage of frag mentation process is characterized by the breakage of spring which are close to each other.