%0 Journal Article
%T NONLINEAR CONSTITUTIVE RELATIONS FOR MAGNETOSTRICTIVE MATERIALS<br>磁致伸缩材料的非线性本构关系
%A Wan Yongping Fang Daining Hwang Keh-Chih
%A <br>万永平
%A 方岱宁
%A 黄克智
%J 力学学报
%D 2001
%I 
%X The magnetostrictive materials usually endure a coupled mechanical-magnetic field when they are in application. Their constitutive relation is essentially nonlinear. From the energy balance equation of electric-magnetic body, by means of the Faraday electric-magnetic induction law and the assumption of magnetostatic approximation, we present two nonlinear constitutive relations of magnetostrictive materials which are called Standard Square and Hyperbolic Tangent models, respectively. Basically, the micro-mechanism of magnetostriction can help understand the nonlinearity of magnetostrictive materials and characterize the moduli in the constitutive relation. When a magnetic field is applied, the magnetic domains will switch to the direction parallel to the external magnetic field. At the same time, the material exhibits elongation in the direction of external magnetic field. Another driving force is the external stress. Upon being applied an external load, the magnetic domains will also switch continuously to the direction perpendicular to the external force. In the meantime, magnetocrystalline anisotropy will retard the rotation of magnetic domains. Thus, the external force must be strong enough to overcome the magnetocrystalline anisotropy effect. There exist different critical stresses for different magnetostrictive materials. To characterize the moduli in the constitutive relations for the one-dimensional problem, we introduce one material function to describe the relation between the external magnetic field associated with the peak piezomagnetic coefficient and the compressive pre-stress based on the published experimental results. The accuracy of the nonlinear constitutive relations is evaluated by comparing the theoretical predictions with experimental results obtained on a Terfenol-D rod operated under both a compressive pre-stress and a bias magnetic field. Results indicate that the Standard Square constitutive relation can accurately predict the experimental results in both the low and the medium magnetic fields, while the Hyperbolic Tangent constitutive relation can reflect the trend of saturation of magnetostrictive strain in the high region of the applied magnetic field. Furthermore, we discuss the Standard Square constitutive relations of the general three-dimension case. For isotropic magnetostrictive materials, a proposed method is presented to characterize the modulus tensors.
%K magnetostrictive material
%K nonlinear behavior
%K constitutive relation<br>磁致伸缩材料
%K 非线性
%K 本构关系
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=5D344E2AD54D14F8&jid=4100DA4A1A3BA1B0CE5AD99AE1DFB420&aid=B98DDB8C8EAC6819&yid=14E7EF987E4155E6&vid=27746BCEEE58E9DC&iid=B31275AF3241DB2D&sid=762CFFBBDED11937&eid=A8E9231F98774741&journal_id=0459-1879&journal_name=力学学报&referenced_num=6&reference_num=8