Theoretical Investigations On Electro-Magneto-Thermo-Elastic Behaviors Of Conductive Materials

With the development of multi-field theoretical for elastomers, it is important to analyze the intensity and dynamic stability of structure components under the effect of strong electromagnetic fields and high temperature. In actual working conditions, materials work in the environment of electromagnetic field and temperature field inevitably, so the relevant analysis of electro-magneto- thermo- mechanics becomes the necessity in the optimization of structure and intensity design. A more perfect theory for the nonlinear electro-magneto- thermo-elastic behaviors is established in this text, and the distribution of current density and thermal effect of conductive thin plate subjected to the multi-pulsed magnetic field and inner inherent electric field, the law of heat conduction influenced by non-uniform electromagnetic field and the nonlinear dynamic response of the plate under the electromagnetic field and temperature field are investigated.Firstly, the induction between the electric field and magnetic field is included in the electro-magneto-thermo-mechanical theory, which has effect on the value and distribution of electromagnetic force. The conception of variable temperature volume force is also introduced by considering the electromagnetic heat effect. During the numerical calculation for the physical model that a current conducting thin plate is subjected to a transverse multi-pulsed magnetic field, the distribution forms of induced electric density, temperature field, in-plane electromagnetic volume forces, variable temperature volume force and also their variation with time are analyzed. We find that the dynamic response of plate impelled by in-plane components of electromagnetic force and variable temperature volume force is related to inner inherent electric field Eo, maximum value Bo of multi-pulsed magnetic field, pulse number n per unit of time and pulse parameterτ.Secondly, the theory of heat conduction influenced by electromagnetic field is perfected by the electromagnetic heat conduction equation deduced from the Boltzmann equation, and the main influencing factors on the heat conductive process are the electric field gradient and the magnetic gradient which is proposed for the first time. Furthermore, the effect of magnetic field on heat conduction depends on the existence of electric field. The existing experimental results can all be discussed based on the mechanism of microcosmic physics. The numerical simulation reveals the rules that the heating rate of heat conduction and final stable temperature are determined by the positive or negative values of electric field gradient and magnetic gradient along the direction of heat conduction. The numerical results are qualitatively consistent with the experimental results.Finally, the conductive thin plate subjected to the non-uniform electromagnetic field and thermal load is considered. The coupling effect between temperature and deformation makes the appearance of beat vibration phenomenon, which the deflection of plate is applied by the in-plane electromagnetic volume forces and variable temperature volume force. The period and the maximum amplitude of beat vibration are enhanced greatly owing to the effect of electromagnetic field, which is important for the research of stability of plate.To sum up, the interaction theory of electro-magneto-thermo-elasticity is improved form our work. Simultaneously, the theoretical basis is provided for predicting the electric, magnetic, thermal and mechanical characteristics of conductive structure in various complex electromagnetic environments, as well as the physical essence of materials in complex electromagnetic field is revealed.