Study Of Singularity Field For Dynamic Propagating Crack-Tip Of Interface In Double Dissimilar Materials

Combined materials are made of two different materials bonded together in some way, while the combining unit is called interface. Interfaces occur widely in the engineering structures such as weld layers between metalic material, solid propulsor layers, heterogeneous layer in composites, layers made of different medium in road and bridge and so on. As a new branch of solid mechanics, interface mechanics is used to analyse and evaluate the mechanical behavior, with the aim of solving strength, life and optimum problem.The viscosity of solid material is the time-dependent deformation properties, arid creep and stress relaxation are the mechanical behaviors associated with viscosity, while almost all the solid materials are viscosity. However, an obvious viscosity can be demonstrated in some polymers, geotechnial materials, and metallic materials in a state of high-speed deformation, while in the mechanical analysis of these materials, viscous effect must be considered.Viscosity effect is the build-in attribute under high strain-rate and high temperature. The viscosity is considered in the dissertation and assumed to be a inverse ration to the power of the plastic strain rate. The constitutive equations of elastoplastic material in 3D is derived, and the elasticity, viscosity and plasticity of material can be logically matched on magnitude, with the analysis on the exponent of singularity at the crack-tip. As a result, fundamental equation is determined on surface at the crack-tip in the incompressible condition.Asymptotci analysis is conducted in the propagating tip fields of plane strain mode???and?propagating crack for the rigid-elastic viscoplastic interface crack in the incompressible condition, with the adoption of the rate-sensitive constitutive relationship. Numerical calculations of governing equations are carried out and the stress-strain fields are obtained at the crack-tip, with the displacement potential function and boundary condition of interface crack-tip The nature of each asymptotic solution is analyzed and the variations of solutions are discussed according to each parameter.Considering viscosity effect of material at propagating interface crack, it is established in this paper the unified continuous singular crack-tip field in rigid-elastic viscoplastic material for mode?,?and?in the incompressible condition. The interface crack-tip is governed by viscosity coefficient(?)?Mach number(?) and singular factor(?). The exploration and study of the paper provides a feasible method for final solutions of the problems of the asymptotic crack-tip field, while theoretical references for solutions of the difficult problems encountered in engineering practices.