Micro-Stress-Field of Lamellar Inclusion in Eutectic Composite Ceramic

2012 ◽  
Vol 204-208 ◽  
pp. 4433-4436 ◽  
Author(s):  
Xie Quan Liu ◽  
Xin Hua Ni ◽  
Jing Zhang ◽  
Xiang Feng Meng
Keyword(s):  
Stress Field ◽  
Composite Ceramic ◽  
Apparent Size ◽  
Phase Cell ◽  
Ceramic Analysis ◽  
Eutectic Composite ◽  
Three Phase ◽  
Stress Boundary Condition ◽  
Stress Boundary ◽  
Remote Stress

According to the interaction between lamellar inclusion and interphase, forth-phase model is suggested to determine the micro-stress-field distribution of three-phase cell in eutectic composite ceramic. On the basis of the volumetric average strain, the effective compliance tensor increment of eutectic composite ceramic is obtained. The remote stress boundary condition of the eutectic composite ceramic is accounted for getting the micro-stress-field of lamellar inclusion in eutectic composite ceramic. Analysis shows that the micro-stress-field of the lamellar inclusion in eutectic composite ceramic is associated with the stiffness and the volume fractions of each component in eutectic composite ceramic, the shape of interphase and lamellar inclusion. The-micro-stress field has apparent size effect: three direction stresses increase with the thickness of lamellar inclusion.

Size Dependent Micro-Stress-Field of Fibers in Eutectic Ceramic Rod

2010 ◽  
Vol 168-170 ◽  
pp. 226-229
Author(s):  
Hai Xing Lu ◽  
Xie Quan Liu ◽  
Xin Hua Ni ◽  
Tao Sun ◽  
Bao Feng Li
Keyword(s):  
Stress Field ◽  
Local Stress ◽  
Apparent Size ◽  
Average Strain ◽  
Size Dependent ◽  
Three Phase ◽  
Stress Boundary Condition ◽  
Stress Boundary ◽  
Remote Stress ◽  
Local Stress Field

Considering the interaction between fiber-inclusion and strong constraining interphase, forth-phase model is suggested to determine the local stress field distribution of three-phase element in eutectic ceramic rod. On the basis of the volumetric average strain, the effective compliance tensor increment of eutectic ceramic rod is obtained. The remote stress boundary condition of the eutectic ceramic rod is accounted for getting the micro stress field of fibers in eutectic ceramic rod. The results show the micro stress field of the fiber-inclusion in eutectic ceramic rod is associated with the stiffness and the volume fractions of each component in eutectic ceramic rod, the shape of interphase and fiber. The micro stress field has apparent size effect: three direction stresses increase with the diameter of fiber- inclusion.

The Mechanical-Stress-Field of Matrix in Eutectic Ceramic Composite

2011 ◽  
Vol 121-126 ◽  
pp. 3607-3611
Author(s):  
Zhao Gang Cheng ◽  
Xin Hua Ni ◽  
Xie Quan Liu
Keyword(s):  
Stress Field ◽  
Mechanical Stress ◽  
Ceramic Composite ◽  
Composite Ceramic ◽  
Composite Ceramics ◽  
Eutectic Composite ◽  
Nano Fiber ◽  
The Matrix ◽  
Stress Boundary Condition ◽  
Stress Boundary

Based on the interaction between nano-fiber and eutectic interphase, forth-phase mode is used to get the mechanical stress field of matrix in eutectic composite ceramics. The effective flexibility increment tensor of eutectic ceramic composite is obtained by the volumetric average strain. The remote stress boundary condition of the eutectic composite ceramis is accounted for getting the mechanical stress field in matrix. The results show the mechanical stress field of the matrix is associated with the stiffness and the volume fractions of each component in eutectic composite ceramic , the shape of interphase and nano-fiber. The stresses in matrix will decrease due to the strong constraining effects of the eutectic interphase. The eutectic interphase make the eutectic composite ceramics strengthen.

Effective Thermal Expansion Coefficient of Eutectic Composite Ceramic Containing Lamellae

2011 ◽  
Vol 121-126 ◽  
pp. 116-120
Author(s):  
Xie Quan Liu ◽  
Yun Wei Fu ◽  
Tao Sun ◽  
Bao Feng Li
Keyword(s):  
Thermal Expansion ◽  
Size Dependence ◽  
Transverse Isotropy ◽  
Composite Ceramic ◽  
Phase Cell ◽  
Eutectic Composite ◽  
Thermal Expansion Coefficients ◽  
Three Phase ◽  
Expansion Coefficients ◽  
Effective Thermal Expansion

According to the microstructures in eutectic composite ceramic containing lamellae, the four phase model, which is composed of lamellae, eutectic interphase, matrix-atmosphere and effective medium, is put forward. Three phase cell that is composed of lamellae, eutectic interphase and matrix-atmosphere can be regarded as a composite inclusion. In view of Eshelby theory, the effective thermal expansion coefficients of eutectic composite ceramic containing the same orientation lamellae are determined. The eutectic composite ceramic is transverse isotropy and has two independent thermal expansion coefficients. The quantitative analysis shows that the effective thermal expansion coefficients have obvious size dependence.

Interaction between two nanoscale elliptical holes with surface tension

2018 ◽  
Vol 24 (5) ◽  
pp. 1556-1566 ◽  
Author(s):  
Shuang Wang ◽  
Cun-Fa Gao ◽  
Zeng-Tao Chen
Keyword(s):  
Surface Tension ◽  
Stress Field ◽  
Hoop Stress ◽  
Elliptical Hole ◽  
Integral Form ◽  
Maximum Hoop Stress ◽  
Stress Boundary Condition ◽  
Elliptical Holes ◽  
Basic Equations ◽  
Stress Boundary

In this paper, the plane problem of two elliptical nanoscale holes with surface tension is investigated. Firstly, the basic equations are given via the complex variable methods. Then, the stress boundary condition caused by surface tension is derived through the integral-form Gurtin–Murdoch model. The problem is finally solved by the conformal mapping along with the series expansion methods. The results show that the stress field decreases as the two holes become further away from each other. When the distance between the two holes is more than three times the sum of their sizes, the interaction between the two holes can be neglected. In addition, the stress field is greatly influenced by the orientation, aspect ratio and size of the holes. The positions of the maximum hoop stress are also discussed. When the two elliptical holes are put close horizontally, the hoop stress around one hole usually obtain its maximum at the endpoint close to the other hole. However, if one elliptical hole is not horizontal, the hoop stress around it will no longer attain its maximum at the endpoints. Another exception is that when one elliptical hole becomes larger, the hoop stress around the smaller hole would tend to achieve a local minimum at the endpoint close to the larger hole.

Micromechanical Strength of Particle in Composite Ceramic with Partial Debonding Interphase

2010 ◽  
Vol 146-147 ◽  
pp. 366-369
Author(s):  
Xin Hua Ni ◽  
Xie Quan Liu ◽  
Bao Hong Han ◽  
Guo Hui Zhong ◽  
Lei Zhao
Keyword(s):  
Equivalent Stress ◽  
Strain Tensor ◽  
Particle Diameter ◽  
Orientation Angle ◽  
Composite Ceramic ◽  
Phase Cell ◽  
Thermodynamic Force ◽  
Three Phase ◽  
Damage Equivalent Stress ◽  
Damage Process

The four-phase model is used to predict the strength of particles in composite ceramic with partial debonding interphase. Firstly the external strain of three-phase cell is determined. Based on the disturbance strain tensor of three-phase cell, the micromechanical stress field of the particle is obtained. Then based on the generalized thermodynamic force of the particle in damage process, the damage equivalent stress of the particle in the three-phase cell can be calculated. As the damage equivalent stress is equal to the ultimate stress of the particle, the micromechanical strength of particles in composite ceramic with partial debonding interphase is obtained. Finally, For Al2O3-ZrO2 composite ceramic with partial debonding interphase, the variations of the micromechanical strength of particles for different orientation angle and different particle diameter are analyzed. The result shows that the micromechanical strength of particles is determined by the 50° orientation three phase cell, and has obvious size dependence. The micromechanical strength of particle will decrease when the particle diameter increase.

Screw Dislocations in a Three-Phase Composite Cylinder Model With Interface Stress

2008 ◽  
Vol 75 (4) ◽  
Author(s):  
Q. H. Fang ◽  
Y. W. Liu ◽  
P. H. Wen
Keyword(s):  
Boundary Condition ◽  
Classical Case ◽  
Interface Stress ◽  
Composite Cylinder ◽  
Screw Dislocations ◽  
Three Phase ◽  
Cylinder Model ◽  
The Matrix ◽  
Stress Boundary Condition ◽  
Stress Boundary

A three-phase composite cylinder model is utilized to study the interaction between screw dislocations and nanoscale inclusions. The stress boundary condition at the interface between nanoscale inclusion and the matrix is modified by incorporating surface/interface stress. The explicit solution to this problem is derived by means of the complex variable method. The explicit expressions of image forces exerted on screw dislocations are obtained. The mobility and the equilibrium positions of the dislocation near one of the inclusions are discussed. The results show that, compared to the classical solution (without interface stress), more equilibrium positions of the screw dislocation may be available when the dislocation is close to the nanoscale inclusion due to consider interface stress. Also, the mobility of the dislocation in the matrix will become more complex than the classical case.

The Damage Finite Element Analysis of Eutectic Composite Ceramic Containing Lamellae

2011 ◽  
Vol 121-126 ◽  
pp. 473-477
Author(s):  
Shu Qin Zhang ◽  
Xin Hua Ni ◽  
Xie Quan Liu ◽  
Ying Chen Ma
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Field ◽  
Composite Ceramic ◽  
Element Model ◽  
Eutectic Composite ◽  
Element Analysis ◽  
Matrix Fracture ◽  
Damage Process ◽  
The Finite Element Model

According to microstructures in eutectic composite ceramic, the finite element model of composite with eutectic interphase is established. The mechanical stress field of eutectic composite ceramic containing lamellae is simulated. APDL programming in ANSYS is used to analyze the damage process of eutectic composite ceramic. Results show that the failure of eutectic composite ceramic is determined by the damage of matrix. As load is increasing, the damage will elongate along the interphase and extend to the internal of matrix. At last the damage arouses matrix fracture.

Toughening Analysis for Eutectic Composite Ceramic Containing Lamellae

2012 ◽  
Vol 204-208 ◽  
pp. 4071-4074
Author(s):  
Xin Hua Ni ◽  
Cheng Chen ◽  
Xie Quan Liu ◽  
Wan Heng He
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Frictional Force ◽  
Composite Ceramic ◽  
Toughening Mechanism ◽  
Eutectic Composite ◽  
Residual Stress Field ◽  
Pull Out

On basis of the residual-stress-field of the composite ceramic, the frictional force on the boundary of the lamellae can be computed. Then the frictional work is determined. The pull-out toughening mechanism is gotten. The result shows that the toughening value is dependent on the size of lamellae: the pull-out toughening value will increase as the thickness of the lamellae increase.

Analysis of the Electro-Mechanical Responses of the Piezoelectric Motor Based on Finite Element Method

2014 ◽  
Vol 697 ◽  
pp. 181-186
Author(s):  
Zi Lei Wang ◽  
Tian De Qiu
Keyword(s):  
Finite Element ◽  
Coupling Effect ◽  
Complex Stress ◽  
Piezoelectric Resonator ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Mechanical Responses ◽  
Stress Boundary Condition ◽  
Piezoelectric Field ◽  
Stress Boundary

The piezoelectric field and structure field of piezoelectric resonator of ultrasonic motor are intercoupling. It is difficult to obtain the solution under some circumstances because of the complex stress boundary condition and the influence of coupling effect. An electro-mechanical coupling finite-element dynamic equation is established on the basis of the Hamilton’s Principle about piezoceramic and elastomer. The equation is decoupled through the shock excitation of the piezoelectric resonator and the piezoelectricity element and material provided by finite-element analysis. As a result, an admittance curve as well as the distribution status of the nodal DOF is obtained, which provides an effective method to solve electro-mechanical coupling problems.

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