The Elastic-viscoplastic Field At The Mixed-mode Interface Propagating Crack-tip

In the practical engineering the interface exists in various of advanced materials,such as Cermet material, the interface composed of pavement and bridge deck, various of composite etc. The mechanical properties of the materials on both sides of the interface are different, which leads to generation, growth and extension. The failure mechanism, extension and arrest of the interface cracks, all have close relation with the properties of the field at the interface crack-tip.The solid materials is the relation with the time variable during the process of failure, for creep, stress relaxation, all can be explained by the materials viscosity. In the practical engineering various of materials for polymer, geotechnical materials and metal materials in the state of high speed deformation have obvious viscosity. During the study of material failure mechanism, the viscosity effect of materials must be considered.Based on the viscosity effect of materials, the constitutive equation of viscous elastic plastic material in three dimensional conditions is applied, through the analysis of the singularity of the compression-shear crack-tip field and the viscosity,elastic and plastic of the materials, and the basic equation of the compression-shear crack-tip field in the incompressible condition is obtained.Through the introduction of the displacement potential functions of the compression-shear crack-tip field, the components of the deformation,velocity,acceleration and strain rate are obtained, and the compression-shear crack-tip field taken into consideration, the expressions of the stress rate components are obtained. The above constitutive equation applied, through non-quantity analysis, the control equation the compression-shear crack-tip field is derived. Combined with the characterization parameters and boundary conditions of compression-shear crack, through numerical analysis of control equations, the stress and strain field of crack-tip is obtained, and then the changing rule of the solution of interface crack-tip field over various of parameters is discussed.The above analysis showed, The changing rule of the stress and strain field of compression-shear interface crack tip is controlled by viscosity coefficient,mach number and singularity exponent, and the frictional effect and load mixed parameter of crack interface have an affect on the changing rule of crack-tip field. The work of this paper mainly focuses on the analysis and solution of the compression-shear interface crack-tip field in the incompressible condition. Interface crack is the newly arisen branch of solid mechanics, which need more attention and analysis of scholars. According to the difference of practical problem, combined with the basic theory of interface mechanics, finally feasible method and reference is advised for the interface fracture problem.