Dynamic Anti-Plane Characteristic of an Infinite Piezoelectric Medium With a Non-Circular Cavity

Author(s):  
Tianshu Song ◽  
Lili Sun ◽  
Diankui Liu

In this paper, dynamic stress concentrations are studied in an infinite piezoelectric medium with a non-circular cavity under time harmonic incident anti-plane shear wave and inplane electric field. Based on complex variable and conformal mapping method, the dynamic stress concentration factors and the electric field concentration factors at the boundary of the non-circular cavity are obtained by applying the orthogonal function expansion technique. Numerical examples about an infinite piezoelectric medium with an elliptic cavity are provided with different elliptic axial length ratios, different wave numbers and different piezoelectric characteristic parameters. The calculating results show that dynamic analyses are very important to an infinite piezoelectric medium with a non-circular cavity at lower frequencies and larger piezoelectric characteristic parameters.

Author(s):  
Tianshu Song ◽  
Shilong Wang

Dynamic interaction is investigated theoretically between a circular cavity and the surface in a semi-infinite piezoelectric medium subjected to time-harmonic incident anti-plane shearing in the present paper. The formulations are based on the method of complex variable and wave function expandedness. Dynamic stress concentration factors at the edge of the circular cavity are obtained by solving boundary value problems with the method of orthogonal function expansion. The calculating results are plotted so as to show how the frequencies of incident wave, the piezoelectric characteristic parameters of the material and the structural geometries influence upon the dynamic stress concentration factors.


Author(s):  
Tianshu Song ◽  
Tamman Merhej ◽  
Qingna Shang ◽  
Dong Li

In the present work, dynamic interaction is investigated theoretically between several circular cavities near the surface in a semi-infinite piezoelectric medium subjected to time-harmonic incident anti-plane shearing. The analyses are based upon the use of complex variable and multi coordinates. Dynamic stress concentration factors at the edges of the subsurface circular cavities are obtained by solving boundary value problems with the method of orthogonal function expansion. Some numerical solutions about two interacting subsurface circular cavities in a semi-infinite piezoelectric medium are plotted so as to show how the frequencies of incident wave, the piezoelectric characteristic parameters of the material and the structural geometries influence on the dynamic stress concentration factors.


Author(s):  
Tianshu Song ◽  
Dong Li ◽  
Lili Sun

In this article, dynamic interaction is investigated theoretically between several circular cavities in an infinite piezoelectric medium under time-harmonic incident anti-plane shear wave load. The theoretical formulations are based upon the use of complex variable and multi-coordinates. Dynamic stress concentration factors at the edges of the circular cavities are obtained by solving boundary value problems with the method of orthogonal function expansion. As examples, some calculating results of two interacting circular cavities in an infinite piezoelectric medium are plotted to show how the frequencies of incident wave, the piezoelectric characteristic parameters of the material and the structural geometries influence on the dynamic stress concentration factors.


2006 ◽  
Vol 324-325 ◽  
pp. 29-32 ◽  
Author(s):  
Tian Shu Song ◽  
Hong Liang Li ◽  
Jung Qiang Dong

In this paper, the dynamic interaction is investigated theoretically between a crack and a circular cavity in an infinite piezoelectric medium under time-harmonic incident anti-plane shearing. The formulations are based on the method of complex variable and Green’s function. The resulting dynamic stress intensity factors at the crack’s tip and dynamic stress concentration factors at the cavity’s edge are obtained with crack-division technique. Numerical results are plotted to show how the frequencies of incident wave, the piezoelectric characteristic parameters of the material and the geometry of the crack and the circular cavity influence upon the dynamic stress intensity factors and dynamic stress concentration factors.


2005 ◽  
Vol 9 ◽  
pp. 183-190
Author(s):  
Jin Xi Liu ◽  
X.L. Liu

This paper is concerned with the interaction of a piezoelectric screw dislocation with a semi-infinite dielectric crack in a piezoelectric medium with hexagonal symmetry. The solution of the considered problem is obtained from the dislocation solution of a piezoelectric half-plane adjoining a gas medium of dielectric constant ε0 by using the conformal mapping method. The intensity factors of stress, electric displacement and electric field and the image force on the dislocation are given explicitly. The effect of electric boundary conditions on the dislocation-crack interaction is analyzed and discussed in detail. The results show that ε0 only influences the electric displacement and electric field intensity factors and the image force produced by the electric potential jump.


2010 ◽  
Vol 452-453 ◽  
pp. 273-276
Author(s):  
Tian Shu Song ◽  
Dong Li ◽  
Ming Yue Lv ◽  
Ming Ju Zhang

The problem of dynamic stress intensity factor is investigated theoretically in present paper for a radial crack on a circular cavity in an infinite piezoelectric medium, which is subjected to time-harmonic incident anti-plane shearing. First, a pair of electromechanically coupled Green’s functions are constructed which indicate the basic solutions for a semi-infinite piezoelectric medium with a semi-circular cavity. Second, based on the crack-division technique and conjunction technique, integral equations for the unknown stresses’ solution on the conjunction surface is established, which are related to the dynamic stress intensity factor at the crack tip. Third, the analytical expression on dynamic stress intensity factor at the crack tip is obtained. At last, some calculating cases are plotted to show how the frequencies of incident wave, the piezoelectric characteristic parameters of the material and the geometry of the crack and the circular cavity influence upon the dynamic stress intensity factors. While some of the calculating results are compared with the same situation about a straight crack and with static solutions.


2012 ◽  
Vol 525-526 ◽  
pp. 293-296
Author(s):  
Tian Shu Song ◽  
Dong Li ◽  
Ming Ju Zhang ◽  
Yue Fa Zhou

Dynamic anti-plane behaviors are studied on two dissimilar piezoelectric media with an interfacial non-circular cavity subjected to time harmonic incident anti-plane shearing. Based on Greens function and conformal mapping method, the dynamic stress concentration factors at the edge of the non-circular cavity are obtained by applying the orthogonal function expansion technique. Numerical cases about two dissimilar piezoelectric media with an elliptic cavity are provided with different elliptic axial length ratio, different wave number and different piezoelectric characteristic parameter. The calculating results show that dynamic analyses are of importance at lower frequencies and larger piezoelectric characteristic parameters.


2006 ◽  
Vol 74 (5) ◽  
pp. 916-922 ◽  
Author(s):  
Xue-qian Fang ◽  
Chao Hu ◽  
Shan-yi Du

The multiple scattering of shear waves and dynamic stress in a semi-infinite functionally graded material with a circular cavity is investigated, and the analytical solution of this problem is derived. The analytical solutions of wave fields are expressed by employing the wave function expansion method, and the expanded mode coefficients are determined by satisfying the boundary condition of the cavity. The image method is used to satisfy the traction-free boundary condition of the material structure. As an example, the numerical solution of the dynamic stress concentration factors around the cavity is also presented. The effects of the buried depth of the cavity, the incident wave number, and the nonhomogeneity parameter of materials on the dynamic stress concentration factors are analyzed. Analyses show that when the nonhomogeneity parameter of materials is <0, it has less influence on the maximum dynamic stress around the cavity; however, it has greater influence on the distribution of dynamic stress around the cavity. When the nonhomogeneity parameter of materials is >0, it has greater influence on both the maximum dynamic stress and the distribution of dynamic stress around the cavity, especially in the case that the buried depth is comparatively small.


1962 ◽  
Vol 29 (2) ◽  
pp. 299-305 ◽  
Author(s):  
Yih-Hsing Pao

Stress concentrations around a circular cavity in an infinitely extended, thin elastic plate, during passage of plane compressional waves, are discussed. The dynamical stress concentration factors are found to be dependent on the incident wave length and Poisson’s ratio for the plate, and, at certain wave lengths, they are larger than those encountered under statical loading.


2008 ◽  
Vol 385-387 ◽  
pp. 389-392
Author(s):  
Tian Shu Song ◽  
Dong Li ◽  
Xin Wang Wang ◽  
Sheng Li Dong

Dynamic interaction is investigated theoretically between a circular cavity and a crack near the surface in a semi-infinite piezoelectric medium subjected to time-harmonic incident anti-plane shearing in this paper. The formulations are based on the method of complex variable and Green’s function. Dynamic stress concentration factors at the edge of the circular cavity and dynamic stress intensity factors at the crack tip are obtained by solving boundary value problems with the method of orthogonal function expansion. The calculating results are plotted to show how the frequencies and the orientation of incident wave, piezoelectric characteristic parameters of the material and the structural geometries influence upon the dynamic stress concentration factor (DSCF) and dynamic stress intensity factor (DSIF).


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