Microcrack damage and nonlinear constitutive behavior of ferroelectric materials - a mesomechanical approach

铁电材料的微裂纹损伤和非线性本构行为——细观力学方法

• 批准号: 5397367
• 负责人: Professor Dr.-Ing. Dietmar Gross
• 金额: --
• 依托单位: Fachgebiet Festkörpermechanik
• 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/5397367?language=en
• 关键词: Microcrack; damage; nonlinear; constitutive; behavior

Microcracking accompanied with domain switching occurs in ferroelectric materials as a result of sufficiently high electric or mechanical loading. It also appears at relatively low load level during cyclic electrical loading. Nucleation, growth and coalescence of microcracks may not only lead to electric and mechanical fatigue and macroscopic cracking, but also degrade the effective properties of materials in the early stage of service. It is the aim of the project to establish a mesomechanically based macroscopic constitutive relation, taking into account domain switching and microcracking as interacting mechanisms. The analysis is based on the investigation of a ferroelectric multidomain unit cell with a single nucleating microcrack. The detailed electromechanical behaviour during electric loading and unloading is studied by analytical methods and numerically by the finite element method. For the meso-to-macro transition, Rice's concept of internal variables and the domain of microcrack growth theory (DMG) are used. The results of the theory will be compared with experimental findings from the literature for typical configurations.

在铁电材料中，由于足够高的电载荷或机械载荷，微裂纹伴随着畴变而发生。它也出现在相对较低的负载水平在循环电负载。微裂纹的形核、扩展和贯通不仅会导致材料的电疲劳、机械疲劳和宏观开裂，而且会降低材料在服役初期的有效性能。该项目的目的是建立一个基于细观力学的宏观本构关系，考虑到域切换和微裂纹的相互作用机制。该分析是基于铁电多畴单裂纹成核单胞的调查。详细的机电行为在电动加载和卸载的分析方法和数值的有限元方法进行了研究。对于细观到宏观的转变，赖斯的内部变量的概念和微裂纹扩展理论（DMG）的域被使用。理论的结果将与文献中的典型配置的实验结果进行比较。