Investigation of size effects in ferroic materials using phase field simulations

使用相场模拟研究铁质材料的尺寸效应

• 批准号: 201207612
• 负责人: Professor Dr.-Ing. Ralf Müller
• 金额: --
• 依托单位: Fachgebiet Kontinuumsmechanik
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/201207612?language=en
• 关键词: Investigation; size; effects; ferroic; materials

The project investigates size effects in ferroic materials by phase filed simulations. In the first funding period the research focus was onferroelectric materials. The size effects in thin films and at crack tips were investigated numerically. In thin films the effect of the film thickness on the poling behaviour was shown. In thin films the lattice mismatch of the electrode material leads to mechanical load in the active material. This influence of the electrode material was demonstrated. In addition, a three dimensional model, which is basedon an invariant formulation, was developed an implemented within the finite element method. The simulations of thin films of ferroelectric materials will be continued. Especially the effect of dislocations at the interface of the electrode and active material will be studied. Furthermore, the methods will be extended to ferromagnetic materials in the next funding period. The investigations focus on the coupling of the ferroelectric and ferromagnetic phase via mechanical deformations at the material interface. To this end a suitable finite element formulation has to be developed that accounts for both ferroic phases in a common simulation. It is anticipated that complex interacting domain structures appear in the ferroelectric as well as in the ferromagnetic phase. The interaction will be studied numerically with regard to size effects.

本计画以相场模拟研究铁性材料的尺寸效应。在第一个资助期，研究重点是铁电材料。数值研究了薄膜和裂纹尖端的尺寸效应。在薄膜中，薄膜厚度对极化行为的影响。在薄膜中，电极材料的晶格失配导致活性材料中的机械负载。证明了电极材料的这种影响。此外，一个三维模型，这是basedon不变的配方，开发和实现内的有限元方法。铁电材料薄膜的模拟将继续进行。特别是在电极和活性材料的界面处的位错的影响将被研究。此外，这些方法将在下一个资助期内扩展到铁磁材料。调查的重点是通过在材料界面的机械变形的铁电和铁磁相的耦合。为此，必须开发一种合适的有限元公式，在一个共同的模拟中考虑两个铁性相。可以预见，复杂的相互作用域结构出现在铁电体以及在铁磁相。相互作用将在数值上研究尺寸效应。