Abstract：A new method is presented to get the precise results about the interaction between a screw dislocation dipole and a linear nano crack in quasicrystals. Firstly, the Gurtin-Murdoch surface/interface theory is successfully applied to nano crack problems of quasicrystal material, and the boundary model with surface stresses of phonon field and phason field is established. Secondly, the linear crack problem is turned into a unit circle orifice problem by using conformal mapping method of the complex function. Then, the exact solutions of this problem are obtained via Cauchy integral theorem. Finally, the numerical results show that surface effect will significant affects the numerical value of stress field image force and image torque of phonon field and phason field, and further changes mechanical properties of quasicrystal materials when the line crack size in quasicrystal materials is reduced to the nanometer level. Namely, the smaller crack size is, the stronger surface effect is, the greater the numerical changes of stress field and image force and image torque of phonon field and phason field. The couple arm orientation of the screw dislocation dipole has a great influence on the extreme value of the image force and its self-balance.
2018, Vol. 39 
