SGER: A Finite Element Model for Thin Film Ferromagnetic Shape Memory Actuators

摘要本研究的长期目标是开发一种基于铁磁形状记忆合金（FSMA）薄膜的新型驱动和传感器件。该项目是北卡罗来纳州州立大学（NCSU）与德国卡尔斯鲁厄大学微系统技术研究所（IMT）合作伙伴之间国际合作的一部分。它将两个研究所的能力（IMT微技术，器件表征和耦合有限元模拟，NCSU -材料测试，建模和耦合有限元模拟）结合到一个独特的跨学科研究活动中，这将促进有前途的新一代器件与纳米和微工程有很大的相关性。在这个小额赠款探索性研究项目中提出的研究的当前阶段解决了对总体目标的两个重要贡献。开发FSMA的新的热-磁-机械模型的第一版。基于PI先前的工作，他的常规SMA模型将被扩展到通过有效磁力模型来考虑温度相关的磁效应。该模型将根据德国合作伙伴提供的实验数据进行验证。2.基于此模型，一种新的多场有限元公式FSMA致动器将随后开发和实施到IMT in-housecode。这将与IMT小组密切合作完成，并要求相互访问，以确保成功完成。然后，有限元模块将使IMT能够继续其自己的程序部分，并将用于基于验证的模拟而不是试错方法来设计和优化薄膜器件。技术优点：最近，该提案的德国合作伙伴推出了基于NiMnGa薄膜的获奖新型驱动机制，其利用铁磁性和常规形状记忆效应的独特组合。这种组合将使微型或纳米器件的制造与集成的传感和驱动能力，具有相当大的性能提高可比机制。然而，成功的器件设计在很大程度上取决于现实模拟工具的可用性，为此，该项目将在任务I中开发第一个FSMA材料热磁机械行为模型。在项目的任务II中，材料模型将被实现为有限元公式，以模拟致动器系统的动态性能。通过IMT和NCSU之间的密切合作，这项研究将成为可能，它将有助于在一个令人兴奋和不断增长的科学领域建立强大而持久的国际伙伴关系。该项目的成果将被纳入MAE 589 D级“自适应结构I --活性材料传感器和致动器”，该项目已由NCSU PI开发。它将无缝地融入课堂的综合方法，结合实验和理论项目，肯定会激发学生对材料的兴趣。

ABSTRACTThe long-term vision of the proposed research project is the development of a novel type of actuation and sensing devices based on ferromagnetic shape memory alloy (FSMA) thin films. The project is part of an international collaboration between North Carolina State University (NCSU) and partners from the Institute for Micro-Systems Technology (IMT) at the University of Karlsruhe, Germany. It combines the capabilities at both institutes (IMT-micro-technologies, device characterization, and coupled finite element simulation, NCSU - materials testing, modeling and coupled finite element simulation) into a unique interdisciplinary research activity, which will promote a promising new generation of devices with great relevance to nano- and micro-engineering. The current phase of the research as proposed in this Small Grant Exploratory Research project addresses two important contributions to the overall goal.1. Development of a first version of a new thermo-magneto-mechanical model forFSMA. Based on previous work by the PI, his model for conventional SMA will beextended to account for temperature-dependent magnetic effects by means of aneffective magnetic force model. The model will be validated against experimentaldata provided by the German partner. 2. Based on this model, a novel multi-field finite element formulation for FSMAactuators will subsequently be developed and implemented into the IMT in-housecode. This will be done in close collaboration with the IMT group and requiremutual visits to guarantee successful completion. The finite element module willthen enable IMT to continue with its own part of the program and will be used fordesign and optimization of the thin-film devices on the basis of verified simulationsrather than trial-and-error methods.TECHNICAL MERIT: Recently, the German partner in this proposal has introduced anaward-winning novel actuation mechanism based on NiMnGa thin films, which makes use of a unique combination of ferromagnetism and conventional shape memory effects. This combination will enable the fabrication of micro- or nano-devices with integrated sensing and actuation capabilities featuring a considerable performance increase over comparable mechanisms. However, the successful device design depends strongly on the availability of realistic simulation tools, and for this purpose, the project will develop the first model for thermo-magneto-mechanical behavior of FSMA material in Task I.In Task II of the project, the material model will be implemented into a finite elementformulation to simulate the dynamic performance of the actuator system.BROADER IMPACT: This research will be possible through the close collaborationbetween IMT and NCSU, and it will help to establish a strong and long-lasting international partnership in an exciting and growing area of science.In addition, the results of the project will be integrated into the class MAE589D "Adaptive structures I - Active materials sensors and actuators", which has been developed by the NCSU PI. It will blend seamlessly into the class's integrated approach, featuring combined experimental and theoretical projects, and it is certain to spark the students' interest in the material.