Effect of Inhomogeneous Deformation on the Response of Shape Memory Alloy Structures

不均匀变形对形状记忆合金结构响应的影响

• 批准号: 1200465
• 负责人: Stelios Kyriakides
• 金额: $ 38.93万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1200465&HistoricalAwards=false
• 关键词: Effect; Inhomogeneous; Deformation; Response; Shape

Shape memory alloys (SMA) like NiTi are increasingly being used in a range of applications including damping and energy absorption, biomedical devices, MEMS, morphing of structures, etc. The goal of this project is to study the role of localized deformations associated with stress induced phase transformation in SMAs on the response of such structures. Modeling the response of these structures to bending, torsion and tension/compression loadings requires material models capable of capturing differences between tension and compression, multiaxial loadings and the potential for localized inhomogeneous deformations. Although some aspects of SMA behavior can be captured by modern constitutive models, localized deformation is not. A combination of experiment and analysis will be used to bridge this gap. Experiments on simple SMA structures like bending of tubes, axial crushing of shells, and lateral crushing of clusters of tubes will be used to illustrate how localized deformations alter the structural response. To support the modeling of such nonlinearities a material characterization effort will be undertaken in parallel to form the basis of adding the missing features to constitutive models. This involves measuring the material behavior under tension, compression and biaxial loading histories at different temperatures and rates. The results will form the basis for calibrating a multi-scale modeling effort to include the missing features in robust three-dimensional constitutive models. The models will in turn be tested by implementing them in finite element models to simulate the structural experiments.The project involves a collaboration between an experimentalist expert on material and structural instabilities and a theorist expert on modeling of smart materials. The cooperation will generate broadly trained researchers who can become future leaders in multidisciplinary research in academia and industry. Undergraduate participation in the project is used to attract them to graduate school. Laboratory demonstrations to high-school pupils including a significant Hispanic representation are used to expand their interest in engineering and science.

NiTi 等形状记忆合金 (SMA) 越来越多地用于一系列应用，包括阻尼和能量吸收、生物医学设备、MEMS、结构变形等。该项目的目标是研究 SMA 中与应力诱导相变相关的局部变形对此类结构响应的作用。对这些结构对弯曲、扭转和拉伸/压缩载荷的响应进行建模需要材料模型能够捕获拉伸和压缩、多轴载荷以及局部不均匀变形的可能性之间的差异。尽管 SMA 行为的某些方面可以通过现代本构模型捕获，但局部变形却不能。将使用实验和分析相结合来弥补这一差距。对简单 SMA 结构（如管弯曲、壳体轴向挤压和管簇横向挤压）的实验将用于说明局部变形如何改变结构响应。为了支持此类非线性的建模，将并行进行材料表征工作，以形成将缺失特征添加到本构模型的基础。这涉及测量不同温度和速率下拉伸、压缩和双轴加载历史下的材料行为。结果将构成校准多尺度建模工作的基础，以将缺失的特征包含在稳健的三维本构模型中。反过来，这些模型将通过在有限元模型中实施来模拟结构实验来进行测试。该项目涉及材料和结构不稳定性方面的实验专家与智能材料建模方面的理论专家之间的合作。此次合作将培养训练有素的研究人员，他们可以成为学术界和工业界多学科研究的未来领导者。本科生参与该项目是为了吸引他们进入研究生院。向高中生（包括重要的西班牙裔代表）进行实验室演示，以扩大他们对工程和科学的兴趣。