Theoretical and experimental investigations of fatigue crack growth in ferroelectrics under cyclic electromechanical loading

循环机电载荷下铁电材料疲劳裂纹扩展的理论和实验研究

• 批准号: 5397378
• 负责人: Professor Dr. Meinhard Kuna
• 金额: --
• 依托单位: Institut für Mechanik und Fluiddynamik
• 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/5397378?language=en
• 关键词: Theoretical; experimental; investigations; fatigue; crack

Fatigue crack behaviour is of most importance for the assessment of reliability and durability of smart structures in engineering practice. The aim of the present research proposal is the qualitative explanation and the quantitative description of fatigue crack growth mechanisms in ferroelectric and piezoelectric ceramic materials. For this purpose an approach is planned, combining experimental investigations, theoretical modelling and numerical simulations. The main emphasis is on the fracture process zone, where domain switching phenomena induce nonlinear effects and control the failure mechanisms. Therefore, micromechanical and phenomenological constitutive models will be developed, implemented into FEM-codes and applied to simulate the fatigue crack behaviour under mechanical, electrical and combined loading. Experiments will be undertaken to investigate the nonlinear effect of domain switching and to measure fracture toughening and fatigue crack growth rates. Suitable fracture criteria and fatigue crack growth laws will be proposed and verified by experiments. The results will provide guidelines for component design and reliability evaluation of smart ferroelectric structures under cyclic electromechanical loading.

在工程实践中，疲劳裂纹行为对智能结构的可靠性和耐久性评估具有重要意义。本研究计划的目的是对铁电和压电陶瓷材料的疲劳裂纹扩展机制进行定性解释和定量描述。为此，计划采用实验研究、理论建模和数值模拟相结合的方法。重点是断裂过程区，区域切换现象引起非线性效应并控制破坏机制。因此，将开发微力学和现象学本构模型，并将其实现到fem代码中，并应用于模拟机械，电气和组合载荷下的疲劳裂纹行为。将进行实验来研究区域切换的非线性效应，并测量断裂韧化和疲劳裂纹扩展速率。提出合适的断裂准则和疲劳裂纹扩展规律，并通过实验进行验证。研究结果将为智能铁电结构在循环机电载荷作用下的构件设计和可靠性评估提供指导。