Interaction between a generalized screw dislocation in the matrix and an inhomogeneity containing an elliptic hole in piezoelectric–piezomagnetic composite materials

2019 ◽  
Vol 24 (10) ◽  
pp. 3080-3091
Author(s):  
Xianghua Peng ◽  
Min Yu ◽  
Yuxuan Yang
Keyword(s):  
Composite Materials ◽  
Screw Dislocation ◽  
Coupling Effect ◽  
Elliptic Hole ◽  
Great Influence ◽  
Image Force ◽  
Plane Shear ◽  
Blunt Crack ◽  
The Matrix ◽  
In Series

The paper deals with the interaction of a generalized screw dislocation and an elliptic inhomogeneity containing a confocal elliptic hole in a magneto-electro-elastic composite material. Exact solutions are derived for the case where the generalized screw dislocation is located in the matrix under a remote anti-plane shear stress field, an in-plane electric field, and a magnetic field. Based on the complex variable method, the complex potentials of both the matrix and the inhomogeneity are obtained in series, and analytic expressions for the generalized stress and strain field, the image force, the generalized stress intensity factor of the blunt crack tip, and the energy release rate are derived explicitly. The presented solutions include some previous solutions, such as pure elastic, piezoelectric, piezomagnetic, and circular inclusions. Typical numerical examples are presented and the influences of the dislocation position, the volume of inhomogeneity, and the elliptic hole on these physical quantities are discussed. The results show that the magneto-electro-elastic coupling effect has a great influence on the image force and the equilibrium position of dislocation, especially when the dislocation approaches the interface; the coupling effect makes the image force on the screw dislocation follow different variation laws in piezoelectric–piezomagnetic composite materials compared with elastic materials.

Interaction between a Screw Dislocation Located in Strained Reinforcement Layer and a Lip-Shaped Crack

2012 ◽  
Vol 182-183 ◽  
pp. 1549-1553
Author(s):  
Min Yu ◽  
You Wen Liu
Keyword(s):  
Stress Intensity Factor ◽  
Screw Dislocation ◽  
Complex Function ◽  
Great Influence ◽  
Image Force ◽  
Longitudinal Shear ◽  
Shear Load ◽  
The Matrix ◽  
In Series ◽  
Shaped Crack

The paper is aim to investigate the interaction of a screw dislocation in strained reinforcement with a lip-shaped crack under remote longitudinal shear load using complex variable method of Elasticity. The exact solution of complex function of the matrix and the renforcement layer are obtain in series form; then, the expressions of stress field, image force and stress intensity factor of crack tip can be derived; finally, numerical disccusions are pesented and the results shows that the lip-shaped crack in reinforcement layer has interference effect on the interaction of dislocation and reinforcement layer, and the eigenstrain in x-direction has little effect on image force; however, the eigenstrain in y-direction has great influence on image force.

A Magnetoelectric Screw Dislocation Interacting with an Elliptical Inhomogeneity Containing a Confocal Rigid Line

2011 ◽  
Vol 239-242 ◽  
pp. 2195-2200 ◽  
Author(s):  
Chun Zhi Jiang ◽  
You Wen Liu ◽  
Chao Xie
Keyword(s):  
Screw Dislocation ◽  
Electric Displacement ◽  
Image Force ◽  
Material Behavior ◽  
Shear Stresses ◽  
Displacement Fields ◽  
Plane Shear ◽  
Elliptical Inhomogeneity ◽  
Rigid Line ◽  
The Matrix

Based on the complex variable method, the magnetoelectroelastic interaction of a generalized screw dislocation with an elliptical inhomogeneity containing a electrically conductive confocal rigid line under remote anti-plane shear stresses, in-plane electric and magnetic loads is dealt with. The generalized screw dislocation is located inside either the inhomogeneity or the matrix. The analytical-functions of complex potentials for stresses, electric displacement fields and magnetic induction fields in both the inhomogeneity and the matrix are derived. The image force acting on the dislocation are also calculated explicitly. The results show that the influence of the rigid line on the interaction effect between a generalized screw dislocation and an elliptical inhomogeneity is significant. In addition, the material behavior also plays an important role on the image force.

A Screw Dislocation Interacting with a Lip-Shaped Crack Bonded by a Strained Reinforcement Layer under Remote Longitudinal Shear Load

2012 ◽  
Vol 490-495 ◽  
pp. 56-60
Author(s):  
Min Yu ◽  
You Wen Liu
Keyword(s):  
Screw Dislocation ◽  
Complex Function ◽  
Image Force ◽  
Longitudinal Shear ◽  
Singularity Analysis ◽  
Infinite Matrix ◽  
Shear Load ◽  
Riemann Boundary ◽  
The Matrix ◽  
Shaped Crack

The interaction between a screw dislocation and a reinforced lip-shaped crack embedded in an infinite matrix subjected to a remote longitudinal shear load is investigated in this paper. By combining the sectionally holomorphic function theory, Cauchy singular integral, singularity analysis of complex functions and Riemann boundary problem, the problem is reduced to solve an elementary complex potentials equation. The general expressions of complex function in the matrix and the reinforcement layer are derived explicitly in series form for the case when the screw dislocation is located in the matrix. The image force acting on the screw dislocation and the stress intensity factor are also calculated. Some numerical results are provided to discuss the effects of dislocation position, material parameters, geometric configurations and eigenstrain on the image force.

On a Screw Dislocation Interacting With Two Viscous Interfaces

2009 ◽  
Vol 76 (5) ◽  
Author(s):  
X. Wang ◽  
E. Pan
Keyword(s):  
Screw Dislocation ◽  
Equilibrium Position ◽  
Time Moment ◽  
Early Time ◽  
Image Force ◽  
Interface Layer ◽  
Critical Value ◽  
Time Dependent ◽  
Interphase Layer ◽  
The Matrix

We investigate a screw dislocation interacting with two concentric circular linear viscous interfaces. The inner viscous interface is formed by the circular inhomogeneity and the interphase layer, and the outer viscous interface by the interphase layer and the unbounded matrix. The time-dependent stresses in the inhomogeneity, interphase layer, and unbounded matrix induced by the screw dislocation located within the interphase layer are derived. Also obtained is the time-dependent image force on the screw dislocation due to its interaction with the two viscous interfaces. It is found that when the interphase layer is more compliant than both the inhomogeneity and the matrix, three transient equilibrium positions (two are unstable and one is stable) for the dislocation can coexist at a certain early time moment. If the inhomogeneity and matrix possess the same shear modulus, and the characteristic times for the two viscous interfaces are also the same, a fixed equilibrium position always exists for the dislocation. In addition, when the interphase layer is stiffer than the inhomogeneity and matrix, the fixed equilibrium position is always an unstable one; on the other hand, when the interface layer is more compliant than the inhomogeneity and matrix, the nature of the fixed equilibrium position depends on the time: the fixed equilibrium position is a stable one if the time is below a critical value, and it is an unstable one if the time is above the critical value. In addition, a saddle point transient equilibrium position for the dislocation can also be observed under certain conditions.

Magnetoelectroelastic Interaction between a Generalized Screw Dislocation and Multiple Circular Inclusions

2010 ◽  
Vol 26 (3) ◽  
pp. 309-316
Author(s):  
M. H. Shen ◽  
F.M. Chen ◽  
S. Y. Hung ◽  
S.N. Chen
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Screw Dislocation ◽  
Analytical Solutions ◽  
Displacement Field ◽  
Complex Variable ◽  
Crack Problem ◽  
Image Force ◽  
Variable Method ◽  
The Matrix

AbstractIn this paper, the interaction of a generalized screw dislocation with multiple circular inclusions perfectly bonded to an unbounded matrix under remote magnetoelectromechanical loadings is dealt with. The analytical solutions of electric field, magnetic field and displacement field either in the inclusions or the matrix are obtained by use of the complex variable method. The image force acting on the magnetoelectric screw dislocation is calculated by using the generalized Peach-Koehler formula. Finally, the influence of material combinations on the image force is examined for several practical examples. The obtained solutions can be used as Green's functions for the analysis of the corresponding magnetoelectric crack problem.

Determination of In-plane Shear Strength of Unidirectional Composite Materials Using the Off-axis Three-point Flexure and Off-axis Tensile Tests

2010 ◽  
Vol 44 (21) ◽  
pp. 2487-2507 ◽  
Author(s):  
G. Vargas ◽  
F. Mujika
Keyword(s):  
Shear Strength ◽  
Composite Materials ◽  
Tensile Tests ◽  
Unidirectional Composite ◽  
Point Of View ◽  
Experimental Point ◽  
Plane Shear ◽  
Lift Off ◽  
Flexure Test

The aim of this work is to compare from an experimental point of view the determination of in-plane shear strength of unidirectional composite materials by means of two off-axis tests: three-point flexure and tensile. In the case of the off-axis three-point flexure test, the condition of small displacements and the condition of lift-off between the specimen and the fixture supports have been taken into account. Some considerations regarding stress and displacement fields are presented. The in-plane shear characterization has been performed on a carbon fiber reinforced unidirectional laminate with several fiber orientation angles: 10°, 20°, 30°, and 45°. Test conditions for both off-axis experimental methods, in order to ensure their applicability, are presented. Off-axis flexure test is considered more suitable than off-axis tensile test for the determination of in-plane shear strength.

Fabrication and Properties of Lignin/Castor Oil-Based Composites

2011 ◽  
Vol 311-313 ◽  
pp. 1535-1538 ◽  
Author(s):  
Hong Juan Wang ◽  
Hai Yan Xiao ◽  
Feng Qiang Sun ◽  
Jian Hua Zhang
Keyword(s):  
Fourier Transform ◽  
Electron Microscope ◽  
Free Radical ◽  
Composite Materials ◽  
Scanning Electron Microscope ◽  
Castor Oil ◽  
Morphology And Structure ◽  
The Matrix ◽  
Facile Route ◽  
Scanning Electron

Novel bio-based composites were developed from maleate castor oil (MACO) and lignin through free radical initiated copolymerization between MACO and diluent monomer styrene(St). The morphology and structure of the composites were characterized by Fourier transform infrared spectroscope (FTIR) and scanning electron microscope (SEM). The mechanical and thermal behaviors of the composites were investigated, which showed the incorporation of a little of lignin in the castor oil based polymer can enhance the tensile properties of the matrix polymer greatly. This work provides a facile route to prepare bio-based composite materials from castor oil and lignin and can be extended to prepare other bio-based materials from reproducible resources.

The Estimation of Thermal Conductivity for Alumina-Epoxy Composite Material with High Filling Volume Fraction

2014 ◽  
Vol 918 ◽  
pp. 21-26
Author(s):  
Chen Kang Huang ◽  
Yun Ching Leong
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Composite Materials ◽  
Physical Model ◽  
Electron Scattering ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
The Matrix ◽  
Transport Theorem ◽  
Good Agreement

In this study, the transport theorem of phonons and electrons is utilized to create a model to predict the thermal conductivity of composite materials. By observing or assuming the dopant displacement in the matrix, a physical model between dopant and matrix can be built, and the composite material can be divided into several regions. In each region, the phonon or electron scattering caused by boundaries, impurities, or U-processes was taken into account to calculate the thermal conductivity. The model is then used to predict the composite thermal conductivity for several composite materials. It shows a pretty good agreement with previous studies in literatures. Based on the model, some discussions about dopant size and volume fraction are also made.

Features of nonlinear in-plane shear deformation of a unidirectional and orthogonally reinforced polymer sheets of composite materials

2021 ◽  
Vol 87 (5) ◽  
pp. 47-55
Author(s):  
A. O. Polovyi ◽  
N. V. Matiushevski ◽  
N. G. Lisachenko
Keyword(s):  
Experimental Data ◽  
Composite Materials ◽  
Shear Modulus ◽  
Maximum Deviation ◽  
Linear Section ◽  
Stress Strain ◽  
Plane Shear ◽  
End Point ◽  
Reinforced Polymer ◽  
Failure Point

A comparative analysis of typical stress-strain diagrams obtained for in-plain shear of the 25 unidirectional and cross-ply reinforced polymer matrix composites under quasi-static loading was carried out. Three of them were tested in the framework of this study, and the experimental data on other materials were taken from the literature. The analysis of the generalized shear-strength curves showed that most of the tested materials exhibit the similar deformation pattern depending on their initial shear modulus: a linear section is observed at the beginning of loading, whereas further increase of the load decreases the slope of the curve reaching the minimum in the failure point. For the three parameters (end point the linear part, maximum reduced deviation of the diagram, tangent shear modulus at the failure point) characterizing the individual features of the presented stress-strain diagrams, approximating their dependences on the value of the reduced initial shear modulus are obtained. At the characteristic points of the deformation diagrams, boundary conditions are determined that can be used to find the parameters of the approximating functions. A condition is proposed for determination of the end point of the linear section on the experimental stress-strain curve, according to which the maximum deviation between the experimental and calculated (according to Hooke’s law) values of the shear stress in this section is no more than 1%, thus ensuring rather high accuracy of approximation on the linear section of the diagram. The results of this study are recommended to use when developing universal and relatively simple in structure approximating functions that take into account the characteristic properties of the experimental curves of deformation of polymer composite materials under in-plane shear of the sheet. The minimum set of experimental data is required to determine the parameters of these functions.

STRUCTURING OF CURED POLYMERIC COMPOSITE MATERIALS IN A MICROWAVE ELECTROMAGNETIC FIELD

2021 ◽  
pp. 3-9
Author(s):  
I. V. Zlobina
Keyword(s):  
Electromagnetic Field ◽  
Composite Materials ◽  
Polymer Composite ◽  
Contact Interaction ◽  
Energy Systems ◽  
Polymeric Composite ◽  
Strength Characteristics ◽  
Polymer Composite Materials ◽  
Reinforcing Fibers ◽  
The Matrix

Based on studies of the microstructure of the matrix of cured polymer composite materials and the area of its contact interaction with reinforcing fibers, the hypothesis of its structuring in the microwave electromagnetic field with an increase in the contact interaction surfaces due to an increase in the number of agglomerates with small transverse dimensions and a decrease in porosity in the macro- and mesopore regions is substantiated. These effects can be used as a basis for increasing the strength characteristics and uniformity of their values after exposure to a microwave electromagnetic field. The results of this work can be used in the development of technologies for finishing hardening of products made of carbon and fiberglass for various transport and energy systems.

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