Some Investigations On The Coupling Among Electro-Magneto-Solid To Smart Structures Containing Giant Magnetostrictive Materials

As a new kind of smart materials, giant magnetostrictive materials (GMM) can generate large magnetostrictive strains due to its sensitivity to environmental magnetic field, which offers lots of potential applications for the purpose of improving the functions of many smart structures and sensor devices. Thus, the investigations on the intrinsic multi-field coupling and nonlinear as well as the analysis method of these properties become the basic research subject in designing and analyzing of GMM smart structures and devices. In this thesis, based on the multi-field coupling nonlinear constitutive relations of GMM obtained by the Electromagnetic Solid Structure Mechanical Group of Lanzhou University, the theoretical analysis on the magnetoelectric (ME) coefficient of laminated GMM-PZT sensors and vibration suppression of laminated beam-type plate with GMM layer are discussed. The main points are as follows:Firstly, aiming at the laminated beam-type structure of electric-magnetic GMM-PZT sensors, based on the constitutive model of GMM which have the unhysteresis multi-field coupling analytical closed form, a formula using system parameters to describe the quasi-static ME coefficient is proposed. The predicting results are in good agreement with the experimental data. Then the hysteresis properties of ME coefficient is described based on the multi-field coupling nonlinear hysteresis constitutive model of GMM. The theoretical results are also agreed quantitatively with experimental results. After that, the influences of system parameters and environment issues on ME coefficient are discussed quantitatively.Secondly, aiming at the conditions that the unsaturatued excitation magnetic field varies at low level, investigations on the magnetic-elastic-temperature multi-field coupling nonlinear constitutive model of the minor loop are carried out. After verifying the theoretical results by comparing the predicting results with the experimental data, the influences of pre-stress and environmental temperature on minor loops are demonstrated quantitatively.Finally, aiming at the vibration suppression of cantilever beam-type laminated plate with GMM layer, a feedback control simulation model is proposed by adopting FEM method. The influences of bias magnetic field, pre-stress and other parameters on the control effects are presented. In addition, the effective damping factor depicting the control effect of laminated location of GMM is obtained.