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1.
Elastic behaviour of a wedge disclination dipole near a sharp crack emanating from a semi-elliptical blunt crack 下载免费PDF全文
The interaction between a wedge disclination dipole and a
crack emanating from a semi-elliptic hole is investigated. Utilising
the complex variable method, the closed form solutions are derived
for complex potentials and stress fields. The stress intensity
factor at the tip of the crack and the image force acting on the
disclination dipole center are also calculated. The influence of the
morphology of the blunt crack and the position of the disclination
dipole on the shielding effect to the crack and the image force is
examined in detail. The results indicate that the shielding or
anti-shielding effect to the stress intensity factor increases when
the wedge disclination dipole approaches the tip of the crack. The
effects of the morphology of the blunt crack on the stress intensity
factor of the crack and the image force are very significant. 相似文献
2.
Elastic behaviour of an edge dislocation near a sharp crack emanating from a semi-elliptical blunt crack 下载免费PDF全文
The interaction between an edge dislocation and a crack
emanating from a semi-elliptic hole is dealt with. Utilizing the
complex variable method, closed form solutions are derived for
complex potentials and stress fields. The stress intensity factor at
the tip of the crack and the image force acting on the edge
dislocation are also calculated. The influence of the morphology of
the blunt crack and the position of the edge dislocation on the
shielding effect to the crack and the image force is examined in
detail. The results indicate that the shielding or anti-shielding
effect to the stress intensity factor increases acutely when the
dislocation approaches the tip of the crack. The effect of the
morphology of the blunt crack on the stress intensity factor of the
crack and the image force is very significant. 相似文献
3.
The solution of a wedge disclination dipole interacting with an annular inclusion and the force acting on the disclination dipole 下载免费PDF全文
The interaction between a wedge disclination dipole and an elastic annular inclusion is investigated. Utilizing the Muskhelishvili complex variable method, the explicit series form solutions of the complex potentials in the matrix and the inclusion region are derived. The image force acting on the disclination dipole centre is also calculated. The influence of the location of the disclination dipole and the thickness of the annular inclusion as well as the elastic dissimilarity of materials upon the equilibrium position of the disclination dipole is discussed in detail. The results show that a stable equilibrium point of the disclination dipole near the inclusion is found for certain combinations of material constant. Moreover, the force on the disclination dipole is strongly affected by the position of the disclination dipole and the thickness of annular inclusion. The repulsion force increases (or the attraction force reduces) with the increase of the thickness of the annular inclusion. An appropriate critical value of the thickness of the annular inclusion may be found to change the direction of the force on the disclination dipole. The present solutions include previous results as special eases. 相似文献
4.
In this paper, we present an analytical solution of the interaction of the nanotube (NT) with a wedge disclination dipole in nanotube-based composites. The corresponding boundary value problem is solved exactly by using complex potential functions. The explicit expression of the force exerted on disclination dipole is given by using the generalized Peach- Koehler formula. As a numerical illustration, both the equilibrium position and the stability of the disclination dipole are evaluated for different material combinations, relative thickness of an NT, surface/interface effects, and the features of the disclination dipole. The results show that as the thickness of the NT layer increases, the NT has a relatively major role in the force acting on the disclination dipole in the NT-based composite. The cooperative effect of surface/interface stresses and the NT becomes considerable as the increase of NT layer thickness. The equilibrium position may occur, even more than one, due to the influences of the surface/interface stress and the NT thickening. The influences of the surface/interface stresses and the thickness of the NT layer on the force are greatly dependent on the disclination angle. 相似文献
5.
Shielding effect and emission criterion of a screw dislocation near an interfacial blunt crack 下载免费PDF全文
Shielding effect and emission criterion of a screw dislocation near
an interfacial blunt crack are dealt with in this paper. Utilizing
the conformal mapping technique, the closed-form solutions are
derived for complex potentials and stress fields due to a screw
dislocation located near the interfacial blunt crack. The stress
intensity factor on the crack tips and the critical stress intensity
factor for dislocation emission are also calculated. The influence
of the orientation of the dislocation and the morphology of the
blunt crack as well as the material elastic dissimilarity on the
shielding effect and the emission criterion is discussed in detail.
The results show that positive screw dislocations can reduce the
stress intensity factor of the interfacial blunt crack tip
(shielding effect). The shielding effect increases with the increase
of the shear modulus of the lower half-plane, but it decreases with
the increase of the dislocation azimuth angle. The critical loads at
infinity for dislocation emission increases with the increase of
emission angle and curvature radius of blunt crack tip, and the most
probable angle for screw dislocation emission is zero. The present
solutions contain previous results as special cases. 相似文献
6.
The model of a screw dislocation near a semi-infinite wedge crack tip inside a nano-circular inclusion is proposed to investigate the shielding effect of nano inclusions acting on cracks. Utilizing the complex function method, the closed-form solutions of the stress fields in the matrix and the inclusion region are derived. The stress intensity factor, the image force, as well as the critical loads for dislocation emission are discussed in detail. The results show that the nano inclusion not only enhances the shielding effect exerted by the dislocation, but also provides a shielding effect itself. Moreover, dislocations may be trapped in the nano inclusion even if the matrix is softer than the inclusion. This helps the dislocation shield crack, and reduces the dislocation density within the matrix. 相似文献
7.
基于Landau-de Gennes理论, 利用松弛迭代法, 研究了混合排列向列相液晶薄盒中–1/2向错引起的有序重构的扩散现象, 给出了–1/2向错的核结构、双轴性结构, 以及盒厚减小时有序重构的扩散. 当盒厚小于15ξ时, 随着盒厚的减小, 向错范围和有序重构区域沿基板方向迅速扩散; 当盒厚减小到临界厚度10ξ时, 有序重构的范围扩散到整个液晶盒中, 以向错中心所对应的平面为界, 指向矢一部分垂面排列, 另一部分沿面排列. 本文的研究对拓扑缺陷对向列相液晶中的亚微米胶体粒子的调节作用具有一定的理论指导意义.
关键词:
混合排列向列相液晶薄盒
–1/2向错
有序重构扩散
松弛迭代法 相似文献