Study Of The Crack Nucleation From A Disclination In A Nanowire

The problem of the crack nucleation from a wedge disclination dipole in nanomaterials is investigated. This study has important theoretical value and scientificsignificance for discussing defects and other mechanics behavior of nano-materials. In thispaper, we have investigated the fundamental solution and the image force of a wedgedisclination, the fundamental solution and the image force of an edge dislocation. And therelaxation of an eccentric negative wedge disclination in a nanowire by nucleation of aGriffith crack is investigated. According to the condition that nanowire interface hascontinual displacement and stress. The explicit solutions of the problem are obtained bythe use of the complex variable method. The achievements in detail are expressed asfollows.The problem of the fundamental solution and the image force of a wedge disclinationis investigated. The influence of surface properties, the location of wedge disclination andthe size of the nanowire on the image force is discussed. The results show that a repulsiveforce or attractive force will act on the wedge disclination for considering the interfaceeffect. When the wedge disclination is closing to the nanowire surface the surface effect ismore obvious. The smaller the radius of the nanowire, the larger the effect of the force.The problem of the fundamental solution and the image force of an edge dislocationis investigated. The influence of surface properties, the location of edge dislocation andthe size of the nanowire on the image force is discussed. The results show that differentsurface properties may cause the glide/climb force to either increase or decrease. Thesmaller the radius of the nanowire, the larger the effect of the glide/climb force.The problem of the relaxation of an eccentric negative wedge disclination in ananowire by nucleation of a Griffith crack is investigated. The influence of surfaceproperties, the location of eccentric negative wedge disclination, the disclination strength,and the size of the nanowire on the stress intensity factors are discussed. The results showthat the larger the disclination strength, the larger the stress intensity factor of the crack tip.When consider the surface effect, the larger the radius of the nanowire, the smaller theeffect of the stress intensity factors; the crack length and the stress intensity factors decreases as the off-center increases; the value of the surface parameter has a significantimpact for the stress intensity factor of the crack tip.