Homogenization-Based Constitutive Models for Magnetorheological Elastomers at Finite Strain

有限应变磁流变弹性体基于均质化的本构模型

• 批准号: 0708271
• 负责人: Pedro Ponte Castaneda
• 金额: --
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0708271&HistoricalAwards=false
• 关键词: Homogenization; Based; Constitutive; Models; Magnetorheological; Homogenization; Based; Constitutive; Models; Magnetorheological

Ponte Castaneda0708271 Magnetorheological elastomers (MREs) are multi-phase,multi-functional material systems consisting of magnetically"hard" or "soft" particles embedded in an elastomeric matrixphase. Because of the magnetic interactions between theparticles, these materials are magnetostrictive and theirmechanical response can be modified smoothly and reversibly inreal time. Conversely, the presence of strain in these materialscan be detected by induced changes in the overall magnetization. Although "macroscopic" (continuum mechanics) approaches for MREshave been in existence since the 1950s, more "microscopic"theories with truly predictive capabilities are much more recentand so far have been restricted to the linear (infinitesimalstrain) regime. The investigator develops nonlinearhomogenization techniques and applies them to generateconstitutive models for magnetorheological elastomers that arevalid in the finite-strain regime. This builds on earlier work bythe investigator for reinforced elastomers and uses extensions ofvariational "linear comparison" homogenization techniques thathave been developed previously. At the theoretical level, themodels account for: (i) the strongly nonlinear response of theconstituents, including nonlinear ferrolectric behavior for theparticles, as well as nonlinear mechanical response for theelastomeric matrix, (ii) microstructural information, such asparticle shape and orientation, as well as their spatial andorientational distribution, (iii) coupled magnetoelasticconstitutive behavior, and (iv) finite deformations. At theapplications level, the methodology is used to optimally selectthe constituent properties (e.g., magnetically hard vs. softparticles, magnetically isotropic vs. anisotropic particles) andthe microstructural variables (e.g., particle shape andconcentration, aligned distribution of orientations vs. randomorientations, etc.) to enhance the magnetostrictive and sensingcapabilities of these materials. Magnetorheological elastomers (MREs) are composite materialswith "smart" or "intelligent" properties. As a consequence ofthese special properties, MREs hold great promise for use assensors and actuators in many industrial applications, includingthe automotive, electronics, and robotic industries. In addition,they are lightweight, inexpensive and easily processed into amyriad of shapes. However, in order to achieve their fullpotential, a better mathematical understanding is necessary oftheir complex -- highly coupled and nonlinear -- macroscopicbehavior, especially in the large-deformation regime. To aid inthis process, the investigator develops a homogenization-basedapproach to accurately model the macroscopic behavior of MREs,incorporating the dependence on the magnetic properties of theparticles, their initial distribution and orientation(microstructure), as well as the evolution of this microstructureunder large deformation. Finally, because of their actuationproperties MREs provide an artificial analogue of human muscle,and the project has implications for other types of smartmaterials, including electroactive polymers (EAPs), which couldfind applications in biotechnology and other areas of Federalstrategic interest.

Ponte Castaneda0708271磁性弹性体（MRES）是多相，多功能材料系统，由磁性“硬”或“软”颗粒组成，这些颗粒嵌入了弹性基体基质中。 由于粒子之间的磁相互作用，这些材料具有磁性性，并且它们的机械响应可以平稳，可逆地变化。 相反，通过诱导的整体磁化变化检测到这些材料范围中应变的存在。尽管自1950年代以来，“宏观”（连续力学）的方法一直存在，但到目前为止，具有真正预测能力的更多“微观”理论更为近来，并且仅限于线性（InfInitesimaltrain）制度。 研究者开发了非线性化技术，并将其应用于有限型晶体制度中Asevalid的磁性弹性体的生成模型。 这是基于研究人员对加强弹性体的早期工作的建立，并使用了先前已经开发出的不同“线性比较”均质化技术的扩展。 在理论层面上，主解释：（i）构成基督的强烈非线性响应，包括粒子的非线性纤下行为，以及eelastomeric矩阵的非线性机械响应，（ii）微结构信息，微结构信息，例如，是产量的形状和方向分布，以及它们的Spatientical and spatientical and spatientical and spatiention CON（IIIIIIIIIIII CON）（IIIIIIIIIIII）（IIIIIIIIIIII CON）行为和（iv）有限变形。 在拨层水平上，该方法用于最佳选择构成特性（例如，磁性硬粒子与软颗粒，磁性各向同性与各向异性颗粒）和微结构变量（例如，粒子形状和偶发性分布，等级的分布及其启动），以及这些随机性的分布，以及这些强度的启动，并增强这些感觉的启动。 材料。 磁性弹性体（MRES）是复合材料的“智能”或“智能”特性。 由于这些特殊物业的结果，MRES在许多工业应用中（包括汽车，电子和机器人行业）中使用了助议器和执行器具有巨大的希望。 此外，它们是轻巧，便宜的，并且很容易处理成形状的杏仁。 但是，为了实现其全电势，对它们的复合物（高度耦合且非线性）是宏观be的必要条件，尤其是在大型形成方案中。 为了帮助这一过程，研究者开发了一种基于均质化的呼吸，以准确地对MRES的宏观行为进行建模，从而纳入了对台面的磁性特性，其初始分布和方向（微结构）的依赖性，以及该微观结构的大型错误。 最后，由于它们的驱动性，MRES提供了人工肌肉的人造类似物，该项目对其他类型的智能材料具有影响，包括电活性聚合物（EAP），可以在生物技术和FederalStratemits的其他领域中找到应用。