內(nèi)布拉斯加大學(xué)林肯分校楊嘉實教授學(xué)術(shù)報告會

報告題目：Magnetoelasticity of Saturated Ferromagnetic Solids

報告時間：??2023年10月14日?21:00?

報告地點： 8號樓8101?（線上同步：騰訊會議512?729?105）

報告人：?楊嘉實 教授

報告人單位：內(nèi)布拉斯加大學(xué)林肯分校

報告人簡介：楊嘉實，內(nèi)布拉斯加大學(xué)林肯分校機械與材料工程系教授。1982年和1985年分別在清華大學(xué)獲得工程力學(xué)專業(yè)學(xué)士和碩士學(xué)位；1988年獲錫拉丘茲大學(xué)機械工程專業(yè)碩士學(xué)位；1993年獲得普林斯頓大學(xué)土木工程專業(yè)博士學(xué)位。1993年至1994年，在密蘇里大學(xué)羅拉分校做博士后；1994年至1995年在倫斯勒理工學(xué)院做博士后。1995年至1997年，在摩托羅拉公司擔(dān)任工程師。1997年以來，在內(nèi)布拉斯加大學(xué)-林肯分校機械與材料工程系擔(dān)任助理教授、副教授、正教授。他的主要研究領(lǐng)域是機電結(jié)構(gòu)和設(shè)備的理論與數(shù)值模擬。

報告摘要：?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.

邀請單位：黃淮學(xué)院建筑工程學(xué)院