Stress Analysis of Wiresaw Slicing Piezoelectric Materials

2000 ◽  
Author(s):  
Fuqian Yang
Keyword(s):  
Electric Field ◽  
Contact Mechanics ◽  
Mechanical Loading ◽  
Piezoelectric Materials ◽  
Electric Displacement ◽  
Stress Singularity ◽  
Potential Fields ◽  
Mechanical Interaction ◽  
Electric Loading ◽  
Linear Piezoelectricity

Abstract Using linear piezoelectricity theory, the stress and electric potential fields in a half infinite piezoelectric material under anti-plane mechanical loading in wiresaw slicing process has been studied by using appropriate boundary conditions and contact mechanics. Both electric field and electric displacement field are singular at the edges of the contact zone between wire and workpiece. The singularity of electric displacement arises from the electric loading and electro-mechanical interaction. Similar to the conventional contact mechanics, stress singularity occurs due to the contribution of both mechanical and electric loading. At a given mechanical loading, electric loading can either increase or decrease the stress applied to the piezoelectric half space in the slicing process, which depends on the relative direction of the electric field to that of mechanical loading.

Analysis of Conducting Rigid Inclusion at the Interface of Two Dissimilar Piezoelectric Materials

1998 ◽  
Vol 65 (1) ◽  
pp. 76-84 ◽  
Author(s):  
Wei Deng ◽  
S. A. Meguid
Keyword(s):  
Function Theory ◽  
Piezoelectric Materials ◽  
Electric Displacement ◽  
Stress Singularity ◽  
Equilibrium Conditions ◽  
Rigid Line Inclusion ◽  
Rigid Line ◽  
Elastic Mismatch ◽  
Square Root Singularity ◽  
Line Inclusion

This paper is concerned with the electro-elastic analysis of a conducting rigid line inclusion at the interface of two bonded piezoelectric materials. By combining the analytic function theory and the Stroh formalism, we were able to obtain closed-form expressions for the field variables. Both the mechanical stresses and the electric displacement are shown to have at least one of the following behaviors: (i) traditional square root singularity; (ii) nonsquare root singularity; and (iii) oscillatory singularity, which depend upon the electro-elastic mismatch at the interface. By using the static equilibrium conditions, the rigid rotation vector of the inclusion is determined and the extended stress singularity factors (ESSF) are evaluated.

Stresses Near the End of an Internal Electrode in Multilayer Electrostrictive Ceramic Actuators

1994 ◽  
Vol 360 ◽  
Author(s):  
Xiao-Yan Gong
Keyword(s):  
Finite Element ◽  
Electric Field ◽  
Electric Displacement ◽  
Electrical Coupling ◽  
Stress Singularity ◽  
Stress Difference ◽  
Finite Element Program ◽  
Coupling Problem ◽  
Internal Electrode ◽  
Element Program

AbstractStresses near the end of an internal electrode in a multilayer electrostrictive ceramic actuator are studied in detail. A finite element program capable of overcoming two major difficulties is developed. The program solves both the mechanical and electrical coupling problem and the nonlinear electric field and electric displacement relationship for these materials. Results indicate that the stress difference between the coupled and the uncoupled cases can only be distinguished when a stress singularity is present. Tensile stresses are found both in front, and behind, the end of an internal electrode. The magnitude of the stresses is predetermined by the material constants.

Macrocrack-Microcrack Interaction in Piezoelectric Materials, Part II: Numerical Results and Discussions

1999 ◽  
Vol 66 (2) ◽  
pp. 522-527 ◽  
Author(s):  
Y.-H. Chen ◽  
J.-J. Han
Keyword(s):  
Electric Field ◽  
Mechanical Strain ◽  
Electric Displacement ◽  
Strain Energy Release ◽  
Numerical Results ◽  
Electric Loading ◽  
Electric Displacement Intensity Factor ◽  
Variable Nature ◽  
Crack Problems ◽  
Microcrack Interaction

Numerical results are shown in figures and tables. The major features for the traditional stress intensity factors and the electric displacement intensity factor against the microcrack location angle and the distance of the microcrack center from the macrocrack tip are discussed. It is shown that, unlike single-crack problems, the mechanical loading and the electric loading are coupled together since the microcrack not only releases the near-tip stresses, but also disturbs the near-tip electric field. Furthermore, the influence of the electric loading on the mechanical strain energy release rate (MSERR) at the macrocrack tip is discussed in detail. It is found that the variable nature of the MSERR against the normalized electric loading is monotonic and proportional wherever the parallel microcrack is located near the macrocrack tip. However, the slope of the MSERR's curve considering microcracking diverges far from those without considering microcracking. This finding reveals that, besides the two sources of microcrack shielding discussed by Hutchinson (1987) for brittle solids, the disturbance of the near-tip electric field due to microcracking really provides another source of shielding for piezoelectric solids.

Effect of Columbic Force on Piezoelectric Fracture

2004 ◽  
Vol 261-263 ◽  
pp. 81-86 ◽  
Author(s):  
Cun Fa Gao ◽  
Pin Tong ◽  
Tong Yi Zhang
Keyword(s):  
Fracture Behaviour ◽  
Piezoelectric Materials ◽  
Normal Component ◽  
Electric Displacement ◽  
Permeable Crack ◽  
Electric Loading ◽  
Non Linear Equation ◽  
Piezoelectric Solid ◽  
Electric Loads ◽  
Crack Faces

This paper studies the effect of the Columbic force on piezoelectric fracture. Bound charges emerge on the upper and lower surfaces of a permeable crack when a piezoelectric solid with the crack is subjected to far-field mechanical/electric loading. Taking into account the Columbic force between the bound charges, we obtain a non-linear equation governing the normal component of electric displacement D2(x1)on the crack faces. The results show that D2(x1)is, in general, not a constant along the crack faces and depends on the mechanical/electric loading conditions, the crack profile and the material properties outside and inside the crack. Furthermore, we examine the Columbic force under low mechanical/electric loads and then discuss the effect of the Columbic force on the fracture behaviour of piezoelectric materials.

Solution for a Semi-Permeable Interface Crack in Elastic Dielectric/Piezoelectric Bimaterials

2008 ◽  
Vol 75 (1) ◽  
Author(s):  
Q. Li ◽  
Y. H. Chen
Keyword(s):  
Electric Field ◽  
Mechanical Loading ◽  
Interface Crack ◽  
Applied Electric Field ◽  
Crack Tip ◽  
Crack Model ◽  
Permeable Crack ◽  
Impermeable Crack ◽  
Silicon Oil ◽  
Elastic Dielectric

A semi-permeable interface crack in infinite elastic dielectric/piezoelectric bimaterials under combined electric and mechanical loading is studied by using the Stroh complex variable theory. Attention is focused on the influence induced from the permittivity of the medium inside the crack gap on the near-tip singularity and on the energy release rate (ERR). Thirty five kinds of such bimaterials are considered, which are constructed by five kinds of elastic dielectrics and seven kinds of piezoelectrics, respectively. Numerical results for the interface crack tip singularities are calculated. We demonstrate that, whatever the dielectric phase is much softer or much harder than the piezoelectric phase, the structure of the singular field near the semi-permeable interface crack tip in such bimaterials always consists of the singularity r−1∕2 and a pair of oscillatory singularities r−1∕2±iε. Calculated values of the oscillatory index ε for the 35 kinds of bimaterials are presented in tables, which are always within the range between 0.046 and 0.088. Energy analyses for five kinds of such bimaterials constructed by PZT-4 and the five kinds of elastic dielectrics are studied in more detail under four different cases: (i) the crack is electrically conducting, (ii) the crack gap is filled with air/vacuum, (iii) the crack gap is filled with silicon oil, and (iv) the crack is electrically impermeable. Detailed comparisons on the variable tendencies of the crack tip ERR against the applied electric field are given under some practical electromechanical loading levels. We conclude that the different values of the permittivity have no influence on the crack tip singularity but have significant influences on the crack tip ERR. We also conclude that the previous investigations under the impermeable crack model are incorrect since the results of the ERR for the impermeable crack show significant discrepancies from those for the semi-permeable crack, whereas the previous investigations under the conducting crack model may be accepted in a tolerant way since the results of the ERR show very small discrepancies from those for the semi-permeable crack, especially when the crack gap is filled with silicon oil. In all cases under consideration the curves of the ERR for silicon oil are more likely tending to those for the conducting crack rather than to those for air or vacuum. Finally, we conclude that the variable tendencies of the ERR against the applied electric field have an interesting load-dependent feature when the applied mechanical loading increases. This feature is due to the nonlinear relation between the normal electric displacement component and the applied electromechanical loadings from a quadratic equation.

scholarly journals Charging of Piezoelectric Cellular Polypropylene Film by Means of a Series Dielectric Layer

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 333
Author(s):  
Pedro Llovera-Segovia ◽  
Gustavo Ortega-Braña ◽  
Vicente Fuster-Roig ◽  
Alfredo Quijano-López
Keyword(s):  
Electric Field ◽  
Corona Discharge ◽  
Dielectric Layer ◽  
Dielectric Breakdown ◽  
Piezoelectric Materials ◽  
High Resistivity ◽  
Internal Electric Field ◽  
Dielectric Polarization ◽  
Surface Flashover ◽  
In Series

Piezoelectric polymer cellular films have been developed and improved in the past decades. These piezoelectric materials are based on the polarization of the internal cells by means of induced discharges in the gas inside the cells. Internal discharges are driven by an external applied electric field. With this polarization method, cellular polypropylene (PP) polymers exhibit a high piezoelectric coefficient d33 and have been investigated because of their low dielectric polarization, high resistivity, and flexibility. Charging polymers foams is normally obtained by applying a corona discharge to the surface with a single tip electrode-plane arrangement or a triode electrode, which consists of a tip electrode-plane structure with a controlled potential intermediate mesh. Corona charging allows the surface potential of the sample to rise without breakdown or surface flashover. A charging method has been developed without corona discharge, and this has provided good results. In our work, a method has been developed to polarize polypropylene foams by applying an insulated high-voltage electrode on the surface of the sample. The dielectric layer in series with the sample allows for a high internal electric field to be reached in the sample but avoids dielectric breakdown of the sample. The distribution of the electric field between the sample and the dielectric barrier has been calculated. Experimental results with three different electrodes present good outcome in agreement with the calculations. High d33 constants of about 880 pC/N have been obtained. Mapping of the d33 constant on the surface has also been carried out showing good homogeneity on the area under the electrode.

The Higher Order Crack Tip Fields for Interfacial Crack between Linear Functionally Graded and Homogeneous Piezoelectric Materials

2014 ◽  
Vol 1015 ◽  
pp. 97-100
Author(s):  
Yao Dai ◽  
Xiao Chong ◽  
Ying Chen
Keyword(s):  
Piezoelectric Materials ◽  
Electric Displacement ◽  
Interfacial Crack ◽  
Crack Tip ◽  
Higher Order ◽  
Functionally Graded ◽  
Linear Functions ◽  
Intensity Factors ◽  
Crack Tip Fields ◽  
Functionally Graded Piezoelectric Materials

The higher order crack-tip fields for an anti-plane crack situated in the interface between functionally graded piezoelectric materials (FGPMs) and homogeneous piezoelectric materials (HPMs) are presented. The mechanical and electrical properties of the FGPMs are assumed to be linear functions of y perpendicular to the crack. The crack surfaces are supposed to be insulated electrically. By using the method of eigen-expansion, the higher order stress and electric displacement crack tip fields for FGPMs and HPMs are obtained. The analytic expressions of the stress intensity factors and the electric displacement intensity factors are derived.

A polycrystal hysteresis model for ferroelectric ceramics

2006 ◽  
Vol 462 (2069) ◽  
pp. 1573-1592 ◽  
Author(s):  
Y Su ◽  
G.J Weng
Keyword(s):  
Electric Field ◽  
Hysteresis Loop ◽  
Ferroelectric Properties ◽  
Electric Displacement ◽  
Hysteresis Loops ◽  
Ferroelectric Ceramics ◽  
Domain Growth ◽  
Thermodynamic Approach ◽  
Hysteresis Model ◽  
Self Consistent

Most key elements of ferroelectric properties are defined through the hysteresis loops. For a ferroelectric ceramic, its loop is contributed collectively by its constituent grains, each having its own hysteresis loop when the ceramic polycrystal is under a cyclic electric field. In this paper, we propose a polycrystal hysteresis model so that the hysteresis loop of a ceramic can be calculated from the loops of its constituent grains. In this model a micromechanics-based thermodynamic approach is developed to determine the hysteresis behaviour of the constituent grains, and a self-consistent scheme is introduced to translate these behaviours to the polycrystal level. This theory differs from the classical phenomenological ones in that it is a micromechanics-based thermodynamic approach and it can provide the evolution of new domain concentration among the constituent grains. It also differs from some recent micromechanics studies in its secant form of self-consistent formulation and in its application of irreversible thermodynamics to derive the kinetic equation of domain growth. To put this two-level micromechanics theory in perspective, it is applied to a ceramic PLZT 8/65/35, to calculate its hysteresis loop between the electric displacement and the electric field ( D versus E ), and the butterfly-shaped longitudinal strain versus the electric field relation ( ϵ versus E ). The calculated results are found to be in good quantitative agreement with the test data. The corresponding evolution of new domain concentration c 1 and the individual hysteresis loops of several selected grains—along with those of the overall polycrystal—are also illustrated.

A Piezoelectric Screw Dislocation Interacting with a Dielectric Crack in a Hexagonal Piezoelectric Material

2005 ◽  
Vol 9 ◽  
pp. 183-190
Author(s):  
Jin Xi Liu ◽  
X.L. Liu
Keyword(s):  
Electric Field ◽  
Screw Dislocation ◽  
Electric Displacement ◽  
Image Force ◽  
Mapping Method ◽  
Piezoelectric Medium ◽  
Intensity Factors ◽  
Potential Jump ◽  
Piezoelectric Screw Dislocation ◽  
Dielectric Crack

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.

Effect of Interface Damage on Loosening Behavior of Acetabular Cup Subjected to Cyclic Loading

2018 ◽  
Vol 941 ◽  
pp. 1841-1845 ◽  
Author(s):  
Yuichi Otsuka ◽  
Kengo Kagaya ◽  
Yuki Hakozaki ◽  
Yukio Miyashita ◽  
Yoshiharu Mutoh
Keyword(s):  
Cyclic Loading ◽  
Mechanical Loading ◽  
Failure Modes ◽  
Fatigue Testing ◽  
Biological Effects ◽  
Stress Singularity ◽  
Testing System ◽  
Acetabular Cup ◽  
Edge Part ◽  
The One

This study aims at experimentally revealing the effects of damages/fractures in HAp coating layer of acetabular cups on loosening behavior of the acetabular cups. Aseptic loosening is occurred due to degradation of fixing force of acetabular cups by biological effects or mechanical loading. However, effects of mechanical loading on loosening behaviour have not been observed yet. In order to simulate cyclic loading conditions of gaits, a testing system which can load entire components of joint including acetabular cups and stem parts was designed. Moreover, by applying two positions of AE sensors during fatigue testing, it was possible to observe the damage behavior of HAp coating. AE measurement detected different failure modes of HAp coating, which were locally occurred at an edge part of the acetabular cup due to stress singularity at that region. In the cases of changing fixation angles, even though damages in simulated cancellous bone surrounding acetabular cups were less occurred, extents of rotational displacements were compatible with the one in an original fixation angle.

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