Structured magnetic circuit for magnetorheological damper made by selective laser melting technology

journal article in Web of Science

en

Eddy currents are the main reason causing for the long response time of a magnetorheological (MR) damper. Eddy currents are often unwanted parasitic phenomenon for many electromagnetic machines working with an alternating magnetic field. Their reduction can be secured by the use of material with high electrical resistivity such as ferrites or soft magnetic composites. These materials, however, exhibit bad mechanical properties and cannot be used in mechanically loaded parts. Eddy currents can also be reduced by the appropriate structure which must secure high conductivity for the magnetic flux but low electrical conductivity for the electric current flowing perpendicularly to the magnetic flux. This leads to complex structures which, in most cases, cannot be manufactured by conventional methods. This paper describes the design, manufacturing and verification of simulations of the magnetic circuit for a MR damper. Structured magnetic cores printed by selective laser melting technology connects the benefits of low-carbon steel (good mechanical properties, high magnetic saturation and high relative permeability) with benefits of sintered materials (high electric resistivity). The results proved that using the potential of additive manufacturing can not only reduce the eddy currents (and thus shorten the response time and reduce losses), but significantly reduce the weight as well. This technology enables the combination of performance parameters of electromagnetic machines, which cannot be reached by any other existing method.

Eddy currents are the main reason causing for the long response time of a magnetorheological (MR) damper. Eddy currents are often unwanted parasitic phenomenon for many electromagnetic machines working with an alternating magnetic field. Their reduction can be secured by the use of material with high electrical resistivity such as ferrites or soft magnetic composites. These materials, however, exhibit bad mechanical properties and cannot be used in mechanically loaded parts. Eddy currents can also be reduced by the appropriate structure which must secure high conductivity for the magnetic flux but low electrical conductivity for the electric current flowing perpendicularly to the magnetic flux. This leads to complex structures which, in most cases, cannot be manufactured by conventional methods. This paper describes the design, manufacturing and verification of simulations of the magnetic circuit for a MR damper. Structured magnetic cores printed by selective laser melting technology connects the benefits of low-carbon steel (good mechanical properties, high magnetic saturation and high relative permeability) with benefits of sintered materials (high electric resistivity). The results proved that using the potential of additive manufacturing can not only reduce the eddy currents (and thus shorten the response time and reduce losses), but significantly reduce the weight as well. This technology enables the combination of performance parameters of electromagnetic machines, which cannot be reached by any other existing method.

selective laser melting, eddy currents, magnetorheological damper, magnetic circuit,beam structures, response time

05.04.2019

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