Non-Linear Homogenization of Porous Anisotropic Materials: Applications to Plastic and Magnetic Shape-Memory Alloys

多孔各向异性材料的非线性均质化：在塑料和磁性形状记忆合金中的应用

• 批准号: 1332965
• 负责人: Pedro Ponte Castaneda
• 金额: $ 34.03万
• 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: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1332965&HistoricalAwards=false
• 关键词: Non; Linear; Homogenization; Porous; Anisotropic

The research objective of this award is to investigate the effect of porosity and to develop constitutive models accounting for this effect in two different types of kinematically constrained material systems. Examples of the first type include low-symmetry metals, such as magnesium and zirconium alloys, which are nominally incompressible polycrystalline aggregates, but which can undergo significant volumetric strains when porosity is present. Examples of the second type include magnetic shape-memory alloys, such as nickel-manganese-gallium systems, which have been found to exhibit "giant" field-induced strains in costly single crystals, but only minimal magnetostriction in cheaper polycrystals. In this case, the presence of porosity can help relax the internal kinematic constraints in the polycrystal due to the strong orientational character of the magnetostriction in the grains that tend to block each other?s strains. The main challenge is to properly account for the dilatational and relaxational effects of the porosity in constitutive models for the response of these materials under general loading conditions. This will be accomplished by means of a recently developed "iterated" nonlinear homogenization technique, which makes use of suitably chosen "linear comparison" media to generate highly accurate and efficient estimates for the coupled, nonlinear response of porous single-crystal and polycrystalline samples of these materials.If successful, the benefits of this research will include improved understanding and advanced modeling of the mechanical properties of high-performance metal alloys for energy-efficient applications in the automotive, aerospace and nuclear industries, as well as of the magneto-elastic response of magnetic shape-memory alloys for applications such as actuators, sensors and energy-harvesting devices. The research is also expected to lead to improved characterization of net-shape metal-forming operations, as well as of ductile failure in polycrystalline materials via void growth and coalescence. In addition, the results will be of interest for modeling of geomaterials, such as ice, halite and olivine. The work may also be relevant for the development of other active material systems, such as certain types of polycrystalline ferroelectrics.

该奖项的研究目标是研究孔隙度的效果，并在两种不同类型的运动型材料系统中开发构成模型。第一种类型的例子包括低对称金属，例如镁和锆合金，它们是名义上不可压缩的多晶骨料，但是当存在孔隙率时，它们可能会出现明显的体积菌株。第二种类型的示例包括磁性 - 记忆合金，例如镍曼加尼亚高级系统，已发现它们在昂贵的单晶中表现出“巨型”野外诱导的菌株，但仅在廉价的多晶中显示了最小的磁曲折。在这种情况下，孔隙率的存在可以帮助放松多晶的内部运动学约束，这是由于晶粒中磁截图的强度定向特征，这些特征倾向于相互阻塞。主要的挑战是正确地说明构成模型中孔隙率在一般加载条件下对这些材料响应的扩张和松弛效应。这将是通过最近开发的“迭代”非线性均质化技术来完成的，该技术利用适当选择的“线性比较”介质来生成高度准确，有效的估计值这些材料。如果成功，这项研究的好处将包括对高性能金属合金的机械性能的理解和高级建模，用于在汽车，航空和核行业中的能源有效应用，以及磁弹性磁形形状 - 内存合金对执行器，传感器和能量收获设备等应用的响应。预计该研究还可以改善净形金属形成操作的表征，以及通过空隙的生长和合并来改善多晶材料中延性的特性衰竭。另外，结果将引起建模地材料（例如冰，卤石和橄榄石）的建模。 这项工作也可能与其他活性材料系统的开发有关，例如某些类型的多晶铁电基质。