Method for analyzing and predicting strength of crack-containing ferroelectric material under effect of force-electricity-heat coupling field

Abstract

The invention discloses a method for analyzing and predicting the strength of a crack-containing ferroelectric material under the effect of a force-electricity-heat coupling field. The method comprises the steps: building a new phase field model of multi-field coupling by considering oval cracks in the ferroelectric material as electric inclusions; solving a force-electricity-heat multi-field coupling problem of crack-containing ferroelectric single crystal; giving hysteresis loops of different electric inclusion models, and controlling the dielectric constant of electric inclusion to improvethe material performance or prevent degradation of the material performance; and obtaining domain structures and stress field distribution of ferroelectric single crystals of different electric inclusion models under the effect of a given electromechanical load in different temperature environments. According to the method disclosed by the invention, the correlation between the evolution of the micro domain structure and the macroscopic local stress concentration of the crack-containing ferroelectric material under the action of the force-electricity-heat coupling field is uniformly expressedby using the effective model. Therefore, a theoretical basis is provided for structural safety design and health prediction of a ferroelectric component under a complex or extreme environmental load.

Description

technical field [0001] The invention relates to a method for analyzing and predicting the strength of a crack-containing ferroelectric material, in particular to a method for analyzing and predicting the strength of a crack-containing ferroelectric material under the action of a force-electricity-thermal coupling field. Background technique [0002] Ferroelectric materials such as BaTiO 3 , PbTiO 3 , PZT, etc., due to its inherent electromechanical coupling effect and rapid response, has become a research hotspot for new functional materials and components. However, ferroelectric materials are mostly brittle materials, and defects such as microcracks will inevitably occur during the preparation process. The existence of these defects destroys the geometric or physical continuity of the structure, and local stress concentration and electric field concentration will occur near the discontinuity area, resulting in mechanical failure of materials and structures, which has attr...

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Problems solved by technology

[0006] (2) There is a lack of systematic research on the ferroelectric domain transformation of cracked ferroelectric materials under the action of mechanical-electric-thermal complex external electric field, the movement of domain walls, the evolution of microstructure and the distribution of stress field at the crack tip.

Therefore, there is a problem that it cannot accurately reflect the physical essence.

[0007] (3) At present, for the finite element method to solve the multi-field coupling problem of cracked ferroelectric materials, the existing commercial finite element software cannot simulate the evolution process of ferroelectric microstructures, and cannot clearly and systematically describe the entire physical image

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