Magnetoelectric and magnetomechanical interactions in compliant composite materials

柔顺复合材料中的磁电和磁力相互作用

• 批准号: 389008375
• 负责人: Professor Dr. Mikhail Chamonine
• 金额: --
• 依托单位: Fakultät Elektro- und Informationstechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/389008375?language=en
• 关键词: Magnetoelectric; magnetomechanical; interactions; compliant; composite

Conventional magnetoelectric (ME) composite materials comprise layers of piezoelectric ceramic or single-crystal materials and ferromagnetic metals or alloys. The efficiency of ME interaction is the highest when the modulation frequency of the external magnetic field coincides with eigenfrequencies of mechanical oscillations in the composite structure due to resonance enhancement of deformations in the piezoelectric layer. Since the constitutive solid-state materials have large elastic constants, the corresponding resonance frequencies are also high (typically in the range betwen 1 kHz and 300 kHz). However, for some applications, e.g. for low-frequency magnetic field sensing or vibration energy harvesting, it would be advantageous to have the mechanical resonance frequency of the composite structure much lower, e.g. in the frequency range below 100 Hz. At the present state of technology, compliant (flexible) polymer materials are promising candidates for realization of flexible ME composites. In general, polymer based smart materials are very interesting for MEMS and microfluidic applications because of the advantages of mechanical flexibility, lower fabrication cost and faster processing over silicon based devices. The purpose of this project is to develop enhanced ME layered composite materials, preferably completely made of compliant (flexible) polymers, and to investigate in detail their ME properties. To optimize ME composite materials, the relevant properties of constitutive materials must be investigated as well. Magnetoactive elastomers (MAEs) will be used as magnetostrictive component. These magnetoactive elastomers comprise micrometer-sized magnetic particles (e.g. iron) dispersed in a soft elastomer (e.g. polydimethylsiloxane, PDMS) matrix. Magnetostrictive properties of MAEs will be investigated in the broad temperature range between -60°C and +60°C and they will be related to the increase of the dynamic shear modulus in external magnetic fields, known as magnetorheological or field-stiffening effect. The Wiedemann effect in MAEs will be investigated as a specific manifestation of magnetostriction. MAE layers must be further combined with compliant (flexible) PE materials to form ME composite materials. Different possibilities of implementing PE layers will be explored. In particular, it is envisaged to investigate PDMS-based micro-structured ferroelectric structures, polyvinylidene fluoride (PVDF) and piezo fibre based sandwich composites. Temperature dependencies of ME interaction efficiency in fabricated composite structures will be determined experimentally. These temperature characteristics must be explained from temperature dependencies of constitutive materials. The achieved progress in understanding of ME and magnetomechanical phenomena in developed soft composite materials could open the way for new applications in smart structures.

传统的磁电(ME)复合材料由多层压电陶瓷或单晶材料和铁磁性金属或合金组成。当外加磁场的调制频率与压电层变形的共振增强引起的机械振动的本征频率重合时，ME相互作用的效率最高。由于本构固态材料具有大的弹性常数，相应的共振频率也很高(通常在1 kHz到300 khz之间)。然而，对于一些应用，例如用于低频磁场传感或振动能量采集，具有低得多的复合结构的机械共振频率将是有利的，例如在低于100赫兹的频率范围内。在目前的技术水平下，柔性(柔性)聚合物材料是实现柔性ME复合材料的很有前途的候选材料。与硅基器件相比，聚合物基智能材料具有机械柔韧性好、制造成本低、加工速度快等优点，因此在MEMS和微流控领域具有广阔的应用前景。该项目的目的是开发增强型ME层状复合材料，最好完全由顺应性(柔性)聚合物制成，并详细研究它们的ME性能。为了优化ME复合材料，还必须研究本构材料的相关性能。磁致伸缩弹性体(MAES)将作为磁致伸缩元件。这些磁活性弹性体由微米级的磁性颗粒(如铁)分散在软弹性体(如聚二甲基硅氧烷，PDMS)基质中。MAES的磁致伸缩性能将在-60°C到+60°C的较宽温度范围内进行研究，这些特性将与外部磁场中动态剪切模数的增加有关，即所谓的磁流变学或场硬化效应。MAES中的维德曼效应将被作为磁致伸缩的一种特殊表现来研究。MAE层必须进一步与顺应性(柔性)PE材料结合，形成ME复合材料。我们将探讨实现PE层的不同可能性。特别是，人们设想研究基于PDMS的微结构铁电结构、聚偏氟乙烯(PVDF)和基于压电纤维的夹层复合材料。制造复合材料结构中ME相互作用效率的温度依赖关系将通过实验确定。这些温度特性必须从本构材料的温度依赖性来解释。已开发的柔性复合材料在磁电效应和磁力现象方面的研究进展为其在智能结构中的新应用开辟了道路。