Electric Dipole Model and Computer Simulation of the Fracture Behavior of a Conductive Crack in a Dielectric Material

2004 ◽  
Vol 855 ◽  
Author(s):  
Tianhong Wang ◽  
Xiaosheng Gao
Keyword(s):  
Fracture Toughness ◽  
Lead Zirconate Titanate ◽  
Electric Dipole ◽  
Fracture Behavior ◽  
Domain Switching ◽  
Dielectric Material ◽  
Dipole Model ◽  
Ferroelectric Ceramics ◽  
Mechanical Fracture ◽  
Microstructural Modeling

ABSTRACTFracture tests on poled and depoled lead zirconate titanate (PZT) ceramics indicate that purely electric fields are able to propagate the conductive cracks (notches) and fracture the samples. To understand the fracture behavior of conducting cracks in ferroelectric ceramics, an electric dipole model is proposed, in which a discrete electric dipole is used to represent the local spontaneous polarization and the force couples are used to represent the local strains. The electric dipole model provides basic solutions for microstructural modeling. The microstructural modeling is based on a domain switching mechanism. The domain structure is simulated with a grid of points where polarizations and strains vary with the applied loads. As a first step study, the microstructural modeling is conducted for a dielectric material with a conductive crack. The simulation result explains why the electric fracture toughness is much higher than the mechanical fracture toughness.

Crack tip 90° domain switching in tetragonal lanthanum-modified lead zirconate titanate under an electric field

1999 ◽  
Vol 14 (7) ◽  
pp. 2940-2944 ◽  
Author(s):  
Fei Fang ◽  
Wei Yang ◽  
Ting Zhu
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Lead Zirconate Titanate ◽  
Powder Processing ◽  
Domain Switching ◽  
Crack Tip ◽  
Lead Zirconate ◽  
Processing Technique ◽  
Ferroelectric Ceramics ◽  
Zirconate Titanate

Lanthanum-modified lead zirconate titanate ferroelectric ceramics (Pb0.96La0.04)(Zr0.40Ti0.60)0.99O3 were synthesized by the conventional powder processing technique. X-ray diffraction experiments revealed that the samples belong to the tetragonal phase with a = b = 0.4055 nm, c = 0.4109 nm, and c/a = 1.013. After being poled, the samples were indented with a 5-kg Vickers indenter, and lateral electric fields of 0.4 Ec, 0.5 Ec, and 0.6 Ec (Ec = 1100 V/mm) were applied, respectively. Field-emission scanning electron microscopy showed that 90° domain switching appeared near the tip of the indentation crack under a lateral electric field of 0.6 Ec. A mechanism of 90° domain switching near the crack tip under an electric field is discussed.

Modeling of electric field induced texture in lead zirconate titanate ceramics

2001 ◽  
Vol 16 (8) ◽  
pp. 2306-2313 ◽  
Author(s):  
Shan Wan ◽  
Keith Bowman
Keyword(s):  
Electric Field ◽  
Interaction Energy ◽  
Lead Zirconate Titanate ◽  
Domain Switching ◽  
Texture Evolution ◽  
Threshold Energy ◽  
Lead Zirconate ◽  
Ferroelectric Ceramics ◽  
Domain Orientation ◽  
Zirconate Titanate

Preferred domain orientation of a piezoelectric ceramic develops through domain switching under electric poling. In previous investigations the critical free energy required for domain switching has been assumed as a constant. This assumption leads to overestimation of the poling-induced texture and provides no explanation for the switching reversal in ferroelectric ceramics after the poling field is removed. In this paper, the contribution of intergranular stress to critical energy for 90° domain switching is investigated. A criterion including intrinsic threshold energy and an interaction energy, which is related to the intergranular stress and the intergranular depolarization field, is proposed. The texture evolution during poling process is simulated using a computational model starting from an initial random domain orientation distribution. The resulted domain orientation distributions under and after poling are predicted. The remanent domain switching after poling is the result of the balance between the interaction energy and intrinsic threshold energy. The final texture is much weaker than that under the electric field. Pole figures of poled Navy VI lead zirconate titanate measured by x-ray diffraction are consistent with the predicted textures.

Effect of Ferroelectric Domain on Fatigue Fracture Behavior in Piezoelectric Ceramics

2013 ◽  
Vol 566 ◽  
pp. 3-6
Author(s):  
Motonori Nakamura ◽  
Chiharu Sakaki ◽  
Masahiko Kimura ◽  
Takehiro Konoike ◽  
Hiroshi Takagi ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Electric Field ◽  
Lead Zirconate Titanate ◽  
Domain Switching ◽  
Paraelectric Phase ◽  
Lead Zirconate ◽  
Fatigue Tests ◽  
Ferroelectric Ceramics ◽  
Pzt Ceramics ◽  
Dc Electric Field

Fatigue tests on lead zirconate titanate (PZT) were performed by using single-edge-V-notched specimens under cyclic mechanical loading with or without superposition of a DC electric field. Fatigue life was prolonged by applying a DC electric field to the PZT ceramics. To estimate the domain contribution, fatigue tests on barium strontium titanate (BST) ceramics in both ferroelectric and paraelectric phase were carried out. The fatigue life of the ferroelectric phase was much shorter than that of the paraelectric phase. Comparing the fatigue lives of two PZT ceramics with different values of coercive electric field (Ec) revealed that the fatigue life of the PZT with higher Ec is about one order of magnitude longer than that with lower Ec when the stress-intensity factor of fatigue test is low. It is therefore concluded that non-180°domain switching probably deteriorates the fatigue life of ferroelectric ceramics.

Influence of Electric Fields on the Fracture Behavior of Ferroelectric Ceramics under Combined Electromechanical Loading

2006 ◽  
Vol 306-308 ◽  
pp. 1199-1204 ◽  
Author(s):  
Zhan Wei Liu ◽  
Dai Ning Fang ◽  
Hui Min Xie
Keyword(s):  
Fracture Toughness ◽  
Electric Field ◽  
Electric Fields ◽  
Crack Extension ◽  
Fracture Behavior ◽  
Ferroelectric Ceramics ◽  
Normal Strain ◽  
Electric Field Direction ◽  
Poling Direction ◽  
Electromechanical Loading

In this paper, fracture behavior of ferroelectric ceramics under combined electromechanical loading was investigated using moiré interferometry. It is found that the influence of electric field on fracture toughness is not very larger in the case that the directions of the poling, electric field and crack extension are perpendicular to each other. When the poling direction is parallel to the crack extension direction and both are perpendicular to the electric field direction, the normal strain measured reduced faster than that calculated by FEM with and without electrical loading as the distance away from the crack tip increases. Fracture toughness decreases obviously as the electric-field intensity increases.

Domain switch toughening in polycrystalline ferroelectrics

2006 ◽  
Vol 21 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Jianxin Wang ◽  
Chad M. Landis
Keyword(s):  
Fracture Toughness ◽  
Crack Growth ◽  
Domain Switching ◽  
Ferroelectric Ceramic ◽  
Material Behavior ◽  
Constitutive Law ◽  
Ferroelectric Ceramics ◽  
The Finite Element Method ◽  
Switching Models ◽  
Domain Switch

Mode I steady crack growth was analyzed to determine the toughening due to domain switching in ferroelectric ceramics. A multi-axial, electromechanically coupled, incremental constitutive theory is applied to model the material behavior of the ferroelectric ceramic. The constitutive law is then implemented within the finite element method to study steady crack growth. The effects of mechanical and electrical poling on the fracture toughness are investigated. Results for the predicted fracture toughness, remanent strain distributions, and domain switching zone shapes and sizes are presented. Finally, the model predictions are discussed in comparison discrete switching models and to experimental observations.

Domain Switch Toughening in Polycrystalline Ferroelectrics

2005 ◽  
Vol 881 ◽  
Author(s):  
Chad M. Landis ◽  
Jianxin Wang
Keyword(s):  
Fracture Toughness ◽  
Crack Growth ◽  
Domain Switching ◽  
Ferroelectric Ceramic ◽  
Material Behavior ◽  
Constitutive Law ◽  
Ferroelectric Ceramics ◽  
The Finite Element Method ◽  
Model Predictions ◽  
Domain Switch

AbstractMode I steady crack growth is analyzed to determine the toughening due to domain switching in poled ferroelectric ceramics. A multi-axial, electromechanically coupled, incremental constitutive theory is applied to model the material behavior of the ferroelectric ceramic. The constitutive law is then implemented within the finite element method to study steady crack growth. The effects of mechanical and electrical poling on the fracture toughness are investigated. Results for the predicted fracture toughness, remanent strain and remanent polarization distributions, and domain switching zone shapes and sizes are presented. Finally, the model predictions are discussed in comparison to experimental observations.

Mathematical model to predict the characteristics of polarization in dielectric materials: The concept of piezoelectrcity and electrostriction

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Mathematical Model ◽  
Electric Field ◽  
Lead Zirconate Titanate ◽  
Dielectric Material ◽  
Strain Curve ◽  
Dielectric Materials ◽  
Lead Zirconate ◽  
Simulation Software ◽  
Constitutive Law ◽  
Basic Material

Model was developed for the prediction of polarization characteristics in a dielectric material exhibiting piezoelectricity and electrostriction based on mathematical equations and MATLAB computer simulation software. The model was developed based on equations of polarization and piezoelectric constitutive law and the functional coefficient of Lead Zirconate Titanate (PZT) crystal material used was 2.3×10-6 m (thickness), the model further allows the input of basic material and calculation of parameters of applied voltage levels, applied stress, pressure, dielectric material properties and so on, to generate the polarization curve, strain curve and the expected deformation change in the material length charts. The mathematical model revealed that an application of 5 volts across the terminals of a 2.3×10-6 m thick dielectric material (PZT) predicted a 1.95×10-9 m change in length of the material, which indicates piezoelectric properties. Both polarization and electric field curve as well as strain and voltage curve were also generated and the result revealed a linear proportionality of the compared parameters, indicating a resultant increase in the electric field yields higher polarization of the dielectric materials atmosphere.

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