Dynamic Electromechanical Fracture of Ferroelectric Ceramics: A Full-Field Approach to Crack Tip Energetics

铁电陶瓷的动态机电断裂：裂纹尖端能量学的全场方法

• 批准号: 1939835
• 负责人: Leslie Lamberson
• 金额: $ 18.56万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1939835&HistoricalAwards=false
• 关键词: Dynamic; Electromechanical; Fracture; Ferroelectric; Ceramics

This project will perform experiments under impact-type loading conditions on two of the most widely used ferroelectric ceramics, in order to further develop dynamic ferroelectric fracture theory. Ferroelectric ceramics have widespread use in advanced technological applications and are considered smart materials due to their ability to provide an electrical signal when given a mechanical load. By exploiting this unique electromechanical effect, these materials can function as sensors and actuators, and are found in a broad spectrum of industrial and civil systems including: transportation fuel injectors, structural health monitoring devices, rocket engines and microvalves, to name a few. One of the main issues with these materials is that they are brittle, and are susceptible to failure from cracking, or fracture. While there is a great deal of theory to help describe how these materials may fracture under well-known loading conditions, very little experimental data and fracture analysis exists that explore ferroelectric ceramic fracture under impact-type loading conditions. The newly gained knowledge will help engineers and designers understand how these smart materials break under complex dynamic loading conditions, which will in turn be used to exploit the smart electromechanical effect to mitigate damage, and consequently increase robustness and functionality in real applications. The faculty member will also host an experimental mechanics learning experience at Drexel's Introduce a Girl to Engineering Day and train undergraduate research scholars.The goal of this research is to determine the anisotropic, dynamic electromechanical response of ferroelectric ceramics under transient, mixed-mode loading conditions using full-field experimental measurement techniques. This goal will be achieved emphasizing experimental investigation, supported by existing dynamic fracture and piezoelectric field theory, finite element modeling and microscopy. Impact fracture experiments will be conducted on poled and unpoled, doped and undoped lead zicronate titanate (PZT), and barium titanate (BaTiO3) with varying electrical and mechanical boundary conditions. Full-field deformation measurements during tests from high-speed imaging will be used to extend a hybrid experimental-computational analysis that extracts relevant crack tip energetics to include coupled electromechanical response and explore meaningful fracture criterion for these unique electromechanical materials. To date, the theoretical fundamentals of linear piezoelectric fracture mechanics have been successfully established, as have important analytical aspects of electromechanical crack tip fields and the role of electric crack face boundary conditions. At the same time, no body of dynamic fracture experiments is available to corroborate with the existing theory and challenge the physical basis (or lack thereof) of the analytical assumptions. The outcome of the experiments and analysis in this work will fill that existing knowledge gap.

该项目将对两种最广泛使用的铁电陶瓷进行冲击型加载条件下进行实验，以进一步发展动态铁电骨折理论。 铁电陶瓷在先进的技术应用中广泛使用，由于其在赋予机械负载时能够提供电信号的能力，因此被视为智能材料。通过利用这种独特的机电效应，这些材料可以用作传感器和执行器，并且可以在各种工业和民用系统中找到：包括：运输燃料喷油器，结构性健康监测设备，火箭发动机和微娃娃瓶，仅举几例。 这些材料的主要问题之一是它们是脆性的，并且容易因破裂或骨折而失败。 尽管有很多理论可以帮助描述这些材料在众所周知的负载条件下如何断裂，但在撞击型载荷条件下探索铁电陶瓷骨折的实验数据和断裂分析很少。 新获得的知识将帮助工程师和设计师了解这些智能材料如何在复杂的动态加载条件下破裂，而这些智能材料又将用于利用智能机电效应以减轻损害，从而提高实际应用中的鲁棒性和功能。该教师还将在Drexel的“介绍一个女孩”中介绍一名女孩，并培训本科研究学者。该研究的目的是使用全面测量测量方法来确定瞬时，混合模式负载条件下的铁电陶瓷的各向异性，动态机电响应。现有的动态断裂和压电场理论，有限元建模和显微镜支持的支持，将强调实验研究。 撞击骨折实验将对具有不同的电气和机械边界条件的螺旋和未固定，掺杂和未依存的铅锌钛酸钛酸钛酸钛酸钛酸钛酸（PZT）进行。 高速成像测试期间的全场变形测量将用于扩展杂交实验计算分析，该分析提取相关的裂纹尖端能量学以包括耦合的机电响应并探索这些独特的机电材料的有意义的裂缝标准。迄今为止，已成功建立了线性压电裂缝力学的理论基本原理，机电裂纹尖端场的重要分析方面以及电裂纹面边界条件的作用。 同时，没有任何动态裂缝实验可以证实现有理论，并挑战了分析假设的物理基础（或缺乏物理基础）。 这项工作中实验和分析的结果将填补现有的知识差距。