Modelling of magneto-electro-thermo-mechanical coupled behavior for the conductors under powerful impulse current and high-velocity friction

Abstract

When the conductors are placed under powerful impulse current, high-velocity friction, strong time-dependent magnetic field, such as the operating conditions for the rails of an electromagnetic launcher, the response of the structure will be strongly influenced by the extraordinary environments. Few experimental tools are directly available to these operating conditions to evaluate the reliability and durability of the conductors. Therefore, a transient multi-field coupling mathematical model is proposed to study the magnetic field, thermal field and structure deformation and the coupling characteristics between them by solving the problems of transient magnetic diffusion, transient heat transfer, quasi-static elasticity and contact mechanics in conductors with finite element method. The model validation is then presented by comparison with the experimental results. It is shown that the proposed multi-field coupling model could better describe the magneto-electro-thermo -mechanical response because of the consideration of the effects of multi-field coupling (EMC) and the interface contact pressure caused by structural deformation. The multiphysics characteristics and the velocity skin effects closely related to the velocity can be correctly described with our model. Especially, the EMC increases the magnetic flux density of the whole conductor, lowers the temperature in the high-temperature region but increases the temperature for the low-temperature region, which will make the temperature distribution more uniform in the conductor. Moreover, the initial section of the conductors is the most vulnerable to damage in terms of the thermal field and structural deformation. These results will be significant to understand the multi-field coupling mathematical modelling process and to study the conductor with extreme operating conditions.