The Elastic-Viscoplastic Field Near Mode II Dynamic Propagating Crack-Tip of Interface in Double Dissimilar Materials

The existence of viscosity effect at the interface of double dissimilar materials has an important impact to the distribution of interface crack-tip field and the properties variety of the interface itself. The singular is considered in crack-tip, and the elastic-viscoplastic governing equations of double dissimilar materials at quasi-static propagating interface crack-tip field are established. The displacement potential function and boundary condition of interface crack-tip are introduced, and the numerical analysis of rigid-elastic viscoplastic interface for mode II are worked out. The stress-strain fields are obtained at the crack-tip and the variations of solutions are discussed according to each parameter. The numerical results show that the viscosity effect is a main factor of interface propagating crack-tip field, and the interface crack-tip is a viscoplastic field that is governed by viscosity coefficient、Mach number and singular factor.

The Asymptotic Elastic-Viscoplastic Field at Mode I Dynamic Propagating Crack-Tip

The viscosity of material is considered at propagating crack-tip. Under the assumption that the artificial viscosity coefficient is in inverse proportion to the power law of the plastic strain rate, an elastic-viscoplastic asymptotic analysis is carried out for moving crack-tip fields in power-hardening materials under plane-strain condition. A continuous solution is obtained containing no discontinuities. The variations of the numerical solution are discussed for mode I crack according to each parameter. It is shown that stress and strain both possess exponential singularity. The elasticity, plasticity and viscosity of material at the crack-tip only can be matched reasonably under linear-hardening condition. The tip field contains no elastic unloading zone for mode I crack.