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.

对于评估工程实践中智能结构的可靠性和耐用性，疲劳裂纹行为至关重要。本研究建议的目的是定性解释和对铁电和压电陶瓷材料中疲劳裂纹生长机制的定量描述。为此，计划了一种方法，结合了实验研究，理论建模和数值模拟。主要重点是裂缝过程区域，其中域切换现象会诱导非线性效应并控制故障机制。因此，将开发微机械和现象学组成模型，将其实施到FEM代码中，并应用于在机械，电气和组合负载下模拟疲劳裂纹行为。将进行实验，以研究结构域切换的非线性效应，并测量裂缝韧性和疲劳裂纹生长速率。通过实验，将提出和验证合适的断裂标准和疲劳裂纹生长法。结果将为循环机电负载下的智能铁电结构的组件设计和可靠性评估提供指南。