| Autor: |
Brannon, R. M., Montgomery, S. T., Aidun, J. B., Robinson, A. C. |
| Předmět: |
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| Zdroj: |
AIP Conference Proceedings; 2002, Vol. 620 Issue 1, p197, 4p |
| Abstrakt: |
If a PZT ferroelectric ceramic is subjected to an electric field while cooled from a high temperature, the micron-sized polarization domains become ordered into a cone-shaped distribution of orientations centered about the poling direction. Shock-induced phase transformation induces elastic stiffening and depolarization, releasing stored electrostatic energy. Local stress is affected by transformation strain, which feeds back to attenuate the extent of transformation. To investigate how microstructure (texture, crystal symmetry, porosity) affects macroscopic response (breakdown, stress, and permittivity, etc.), we also simulate PZT explicitly at the grain scale. The electrical behavior of PZT depends on the stress at the microscale domains, which can deviate significantly from the macroscopic stress because of porosity. Our macroscopic model couples pore collapse to both the local pressure and shear stress and a distribution in microscale stress is estimated according to the porosity level, permitting high stress regions to depole before lower stress regions. Overviews of these concepts are given. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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