内布拉斯加大学林肯分校杨嘉实教授学术报告会

报告题目：Magnetoelasticity of Saturated Ferromagnetic Solids

报告时间：  2023年10月14日 21:00 

报告地点： 8号楼8101 （线上同步：腾讯会议512 729 105）

报告人： 杨嘉实 教授

报告人单位：内布拉斯加大学林肯分校

报告人简介：杨嘉实，内布拉斯加大学林肯分校机械与材料工程系教授。1982年和1985年分别在清华大学获得工程力学专业学士和硕士学位；1988年获锡拉丘兹大学机械工程专业硕士学位；1993年获得普林斯顿大学土木工程专业博士学位。1993年至1994年，在密苏里大学罗拉分校做博士后；1994年至1995年在伦斯勒理工学院做博士后。1995年至1997年，在摩托罗拉公司担任工程师。1997年以来，在内布拉斯加大学-林肯分校机械与材料工程系担任助理教授、副教授、正教授。他的主要研究领域是机电结构和设备的理论与数值模拟。

报告摘要： In ferromagnetic solids, microscopic magnetic moments may align themselves to form regions with spontaneous magnetization below the Curie temperature. This is because of the exchange interaction among neighbor magnetic moments, which is quantum mechanical in nature. In saturated ferromagnets, the magnetization vector has a fixed magnitude and can change its direction only. A disturbance of the aligned magnetic moments can propagate as what is called spin waves. In deformable materials, elastic waves may interact with spin waves, which is referred to as phonon-magnon interaction. This is an interdisciplinary research area with limited involvement from the mechanics community at present. This talk is based on the two-continuum model for saturated ferromagnetic solids by H.F. Tiersten. Continuum modeling of phonon-magnon interactions has a few unique and interesting features. In addition to the usual magnetic body force and couple in nonlinear magnetoelasticity, the short-range exchange interaction may be described by distributed surface couples which leads to a magnetization gradient theory. The angular momenta associated with the magnetic moments need to be considered for spin waves. In addition, the saturation condition on magnetization functions as a constraint mathematically. This has implications in the constitutive relations of these materials. Solutions to a few relatively simple problems are presented. This includes the propagation of plane waves, waves and vibrations in plates, and the three-wave interaction of phonons, magnons and photons.

邀请单位：黄淮学院建筑工程学院