Nonlinear Field-Coupling Responses of Adaptive Functionally Graded Structures

自适应功能梯度结构的非线性场耦合响应

• 批准号: 1030836
• 负责人: Anastasia Muliana
• 金额: $ 36.42万
• 依托单位: Texas A&M Engineering Experiment Station
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1030836&HistoricalAwards=false
• 关键词: Nonlinear; Field; Coupling; Responses; Adaptive

Adaptive structures made of composite materials that can respond and adapt to various external stimuli are appealing for the development of multi-tasking intelligent systems. This study focuses on characterizing nonlinear properties and understanding performance of adaptive structures subjected to elevated temperatures, mechanical loading, and high electric field. The adaptive composite structures to be studied consist of ferroelectric ceramic and metal constituents whose compositions and micro-structural arrangements vary continuously through the thickness - such systems are known as functionally graded materials or FGMs. The nonlinearity is due to thermo-electro-mechanical coupling effects. For example, ferroelectric ceramics can experience polarization switching under high compressive stresses and hysteresis electric fields. The objectives of this investigation are to manufacture adaptive functionally graded composites using a powder metallurgy method; test the composite samples at different thermo-electro-mechanical histories, including quasi-static, creep-relaxation, and hysteresis loading; and establish an analytical and computational framework for predicting nonlinear response and simulating shape changes in adaptive structures in response to various external stimuli.An investigation of the thermo-electro-mechanical coupling effects will open an opportunity to further explore long-term material degradation due to oxidation and aging, and fatigue failure mechanisms in intelligent structures. These research activities will contribute to a graduate course development in multifunctional materials and structures, creating visualization and animation of shape changes in adaptive structures, and involving undergraduate and graduate students as well as high school teachers in scientific research. The analysis tools and characterization methods can benefit many industries that manufacture and use devices made from adaptive composite materials, by reducing cost and effort in material characterization requirements.

复合材料自适应结构能够对各种外界刺激做出响应和适应，是多任务智能系统的发展方向。这项研究的重点是表征非线性特性和理解性能的自适应结构受到高温，机械载荷和高电场。要研究的自适应复合结构由铁电陶瓷和金属成分组成，其成分和微观结构排列在厚度上连续变化-这种系统被称为功能梯度材料或FGM。非线性是由于热-电-机械耦合效应。例如，铁电陶瓷可以在高压应力和滞后电场下经历极化切换。本研究的目的是利用粉末冶金方法制备自适应功能梯度复合材料，并对复合材料试样进行不同的热-电-机械历史测试，包括准静态、蠕变-松弛和滞后加载;建立了一个分析和计算框架，用于预测自适应结构响应于各种外部刺激的非线性响应和模拟形状变化。热-电-机械耦合效应将为进一步探索由于氧化和老化引起的长期材料退化以及智能结构中的疲劳失效机制提供机会。这些研究活动将有助于多功能材料和结构的研究生课程开发，创建自适应结构中形状变化的可视化和动画，并使本科生和研究生以及高中教师参与科学研究。分析工具和表征方法可以通过降低材料表征要求的成本和努力而使制造和使用由自适应复合材料制成的装置的许多行业受益。