DYNAMIC CRACK-TIP FIELD IN AN ELASTIC-VISCOPLASTIC MATERIAL
粘弹塑性材料动态裂纹尖端场

The asymptotic analysis of he stress and strain field at a propagating crack tip is given by means of an elastic-viscoplastic model. It is assumed that the viscosity effect can be neglected for elasticity strain, and only for plasticity strain, the viscosity is significant. By use of this model, the constitutive relations of a rate sensitive material and the dynamic equations of the stress and strain field a crack-tip are derived. The stress and strain singularity exponent of crack-tip field is given by means of the asymptotic analysis. The matching condition among elastisity, plastisity and viscosity is discussed. For anti-plane shear crack the detailed analysis is given. The numerical calcula tions are carried out for various parameters of materials. The feature of the numerical solutions is discussed in detail.