Crack growth in ferroelectrics driven by cyclic electric loading

循环电负载驱动的铁电体裂纹扩展

• 批准号: 5397373
• 负责人: Professor Dr.-Ing. Jürgen Rödel
• 金额: --
• 依托单位: Fachgebiet Nichtmetallisch-Anorganische Werkstoffe
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2002
• 资助国家: 德国
• 起止时间: 2001-12-31 至 2005-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5397373?language=en
• 关键词: Crack; growth; ferroelectrics; driven; cyclic

Prior work from the literature of non-conducting cracks indicates that ferroelectrics can exhibit crack growth due to electrical cycling only with the electrical field perpendicular to the crack propagation direction. A clear quantitative and mechanistic understanding about the influences of prior poling, polarity and frequency of the cyclic electric field, however, is still missing. In the experimental part of this project, crack propagation of through thickness cracks in DCB specimens in PZT due to electrical cycling will be investigated with and without a mechanical preload. Switchable strain and macroscopic material characterization will also be performed. The theoretical part of the project will provide switching zones for 90° switching, for 180° switching and will include the piezoelectric effect in order to compute the stress intensity factor at the crack tip via an evaluation of the tractions along a contour integral around the crack tip. A further consistency check of the model is afforded by calculating the specimen geometries where a stable crack path is obtained under mixed mechanical and cyclic electrical loading.

来自非导电裂纹的文献的先前工作表明，铁电体可以表现出由于电循环而导致的裂纹生长，仅在电场垂直于裂纹扩展方向的情况下。然而，关于周期电场的极化、极性和频率的影响，仍然缺乏一个清晰的定量和机理性的理解。在本项目的实验部分，裂纹扩展的厚度裂缝DCB标本在PZT由于电循环将进行调查，没有机械预载荷。还将进行可切换应变和宏观材料表征。该项目的理论部分将提供90°切换和180°切换的切换区，并将包括压电效应，以便通过评估裂纹尖端周围沿着轮廓积分的牵引力来计算裂纹尖端的应力强度因子。进一步的一致性检查的模型提供了通过计算试样的几何形状，其中一个稳定的裂纹路径下获得混合机械和循环电载荷。