Effect Of External Magnetic Field And Stress On Propagation Behavior Of Thickness-twist Waves

Magnetostrictive material is a new type of intelligent material,which can realize the conversion between mechanical energy and magnetic energy.Its magnetic-force multi-field coupling effect makes it the preferred material for making sensors,magnetic control devices,mi crowave devices and other electronic products.It shows attractive application prospects in the fields of signal processing,automatic control,microwave communication and emerging intelligent material systems and structures.Piezomagnetic / elastic layered composites or structures composed of magnetostrictive materials and elastic materials are the basic forms of various magnetic components,and many possible applications are closely related to the propagation of elastic waves.therefore,some basic wave p roblems in transversely isotropic piezomagnetic / elastic composites or structures will be studied in this paper :1.The effect of magnetic field on the torsional wave propagation characteristics of thickness in an inhomogeneous plate composed of piezomagn etic materials and elastic materials is studied.The effective material constant of piezomagnetic materials varies with the change of magnetic field.Based on the continuity condition at the interface between piezomagnetic material and elastic material,th e displacement component and amplitude ratio of reflected wave to incident wave are obtained.The correctness of the results is verified by the conservation of energy.The numerical results show that there is no energy capture phenomenon in the designed st ructure,but the energy capture phenomenon occurs when the magnetic field is applied,and the reflected wave and transmitted wave disappear under a certain combination of incident frequency and magnetic field.2.The band gap characteristics of elastic wa ves in one-dimensional periodic layered structures of magnetostrictive materials and elastic materials are studied.The vertical and oblique propagation of elastic wave and the effects of external magnetic field,prestress and component ratio on the propag ation characteristics are considered.The transmission coefficient is used to verify the correctness of the results.The dispersion equation is calculated by the transfer matrix method,and the propagation characteristics of elastic waves in periodic struc tures are analyzed.The results show that the magnetic field strength has a great influence on the band gap characteristics of elastic wave,and a new band gap appears in the magnetic / elastic material structure,and the influence of prestress on the prop agation characteristics of elastic wave is mainly reflected in the weakening of magnetic field.the band gap of elastic wave transmission is affected by the material component ratio,and the larger the difference is,the wider the band gap frequency range is.In particular,it is pointed out that the constitutive equation of nonlinear magneto-elastic coupling is considered in this paper,which is linearized to solve the specific wave problem,and brings new elastic wave physical phenomena(resonance phenomenon,new band gap,etc.).The results of this paper have certain guiding significance for the analysis and design of magnetoelastic composite structure devices.