Integral Methodology for the Multiphysics Design of an Automotive Eddy Current Damper

Abstract

The present work reports an integrated (experimental and numerical) methodology that combines the development of a finite element multiphysics model with an experimental strategy to optimally design an eddy current damper for automotive suspensions. The multiphysics model couples the whole set of time-dependent electromagnetic, thermal, mechanical, and fluid–wall interaction (CFD) partial differential equations. The developed FE model was validated against both literature model predictions and in-house experimental data. The electromagnetic model takes into account the magnetic material characteristics of the ferromagnetic material and iron poles. Loss separation and the Jiles–Atherton hysteresis models were invoked to determine the heat generated in the soft iron parts. The computation of the fluid–wall interaction phenomena in the air gap allowed for the prediction of the temperature field across the solid materials, including the magnets. The design of the EC damper addresses the effects of the geometries of the stator and rotor, as they are the most critical geometries for maximizing the functions of an eddy current damper. The magneto-thermal simulations suggested that the heating of the permanent magnets remains within a safe region over the investigated operational frequency range of the eddy current damper.

Multiphysics Design of an Automotive Regenerative Eddy Current Damper

“…This ratio determined the pitch size that maximised the damping coefficient. The damping coefficient should then be maximised with respect to the IP height-to-pole pitch size ratio, as we previously demonstrated in [24]. The maximum value of the proposed REC device was attained at 0.27 of the aforementioned ratio, which was within the previously found range of 0.21-0.29 [24].…”

“…The design strategy and performance evaluation of an EC damper [24] were illustrated in a previous work, in which a multi-physics framework was adopted, and the final predictions were experimentally validated against laboratory damping test results. The aim of this work was to present an evolution of the previous device by combining a new regenerative function, hereinafter named REC damper.…”

“…The novel REC damper was designed according to the same methodology previously presented for an EC damper [24]. The external load (Figure 3) that acts on the REC damper is electrically connected to each phase of the coils.…”

“…It becomes even more critical for multi-physics computation, since several coupled fields can only converge when the mesh discretization error is minimal for each field. The optimal discretisation strategy undertaken here is the same as that used for the previous work [24]. The pure simplified EC damper geometry, which represents the worst scenario, was considered to assess the mesh sensitivity for thermal field.…”

“…In a previous work [24], an EC damper was designed and developed using a multiphysics design approach. The main goal of this study was to design and develop an integral device that combined the functions of an EC damper with regenerative functions (regenerative eddy current-REC) for a B-class passenger vehicle.…”