A Dynamic Discrete Dislocation Plasticity study of elastodynamic shielding of stationary cracks
نویسندگان
چکیده
Employing Dynamic Discrete Dislocation Plasticity (D3P), an elastodynamic analysis of the shielding of a stationary crack tip by dislocations is studied. Dislocations are generated via FrankRead sources, and make a negligible contribution to the shielding of the crack tip, whereas dislocations generated at the crack tip via homogeneous nucleation dominate the shielding. Their effect is found to be highly localised around the crack, leading to a magnification of the shielding when compared to time-independent, elastostatic predictions. The resulting attenuation of KI(t) is computed, and is found to be directly proportional to the applied load and to √ t.
منابع مشابه
A dynamic discrete dislocation plasticity method for the simulation of plastic relaxation under shock loading
In this article, it is demonstrated that current methods of modelling plasticity as the collective motion of discrete dislocations, such as two-dimensional discrete dislocation plasticity (DDP), are unsuitable for the simulation of very high strain rate processes (106 s−1 or more) such as plastic relaxation during shock loading. Current DDP models treat dislocations quasi-statically, ignoring t...
متن کاملAnalysis of Multiple Yoffe-type Moving Cracks in an Orthotropic Half-Plane under Mixed Mode Loading Condition
The present paper deals with the mixed mode fracture analysis of a weakened orthotropic half-plane with multiple cracks propagation. The orthotropic half-plane contains Volterra type glide and climb edge dislocations. It is assumed that the medium is under in-plane loading conditions. The distributed dislocation technique is used to obtain integral equations for the dynamic problem of multiple ...
متن کاملMultiple moving cracks in an orthotropic strip sandwiched between two piezoelectric layers
In this paper, the solution of a moving Volterra-type screw dislocation in an orthotropic layer, bonded between two piezoelectric layers is obtained using complex Fourier transform. The dislocation solution is then employed as strain nuclei to derive singular integral equations for a medium weakened by multiple moving cracks. These equations, which are classified as, Cauchy singular equations, ...
متن کاملMultiple Moving Cracks in a Nonhomogeneous Orthotropic Strip
The problem of several finite moving cracks in a functionally graded material is solved by dislocation technique under the condition of anti-plane deformation. By using the Fourier transform the stress fields are obtained for a functionally graded strip containing a screw dislocation. The stress components reveal the familiar Cauchy singularity at the location of dislocation. The solution is em...
متن کاملElastodynamic image forces on dislocations
The elastodynamic image forces on edge and screw dislocations in the presence of a planar-free surface are derived. The explicit form of the elastodynamic fields of an injected, quiescent screw dislocation are also derived. The resulting image forces are affected by retardation effects: the dislocations experience no image force for a period of time defined by the arrival and reflection at the ...
متن کامل