The asymptotic field of a dynamically growing crack in a viscoelastic materia

A mechanical model of a fracturing viscoelastic material was developed to investigate viscous effects in a dynamically growing crack-tip field. It was shown that in the stable creep-growing phase, elastic deformation and viscous deformation are equally dominant in the near-tip field, and stress and strain have the same singularity, namely, (σ, ε) ∝ r ^−1/n−1). The asymptotic solution of separating variables of stress, stain and displacement in the crack-tip field was obtained by asymptotic analysis, and the resulting numerical value of stress and strain in the crack-tip field was obtained by the shooting method and the boundary condition of a mode I crack. Through numerical calculation, it was shown that the near-tip fields are mainly governed by the creep exponent n and Mach number M. When n → ∞, the asymptotic solution of a viscoelastic material can be degenerated into that of Freund’s elastic-ideally plastic material by analyzing basic equations. TANG Li-qiang was born in 1948. He is a professor of Harbin Engineering University. His current research interests include fracture and damage mechanics etc.