Experimental, theoretical, and numerical investigations have been carried out to evaluate resonance frequency and stiffness of a magnetic bead chain in the magnetic filed. Chains formed on a solenoid coil were vibrated by the sine-wave excitation and impact methods and the resonance frequency was deduced. It showed little dependency on the magnetic flux density and the bead diameter, because both the equivalent stiffness and the chain length were large in accordance with the increase of the magnetic flux density. These characteristics were confirmed by a theoretical consideration based on an assumption of potential energy minimization and a numerical calculation with the Distinct Element Method. Stiffness of the chain was directly measured by observation of chain deflection in inclined gravitational field and it also confirmed the dynamically deduced characteristics. It was concluded that the resonance frequency was 20–60 Hz and the static stiffness at the top of the chain was 10−4–10−2 N/m. The investigation is utilized for the improvement of the two-component magnetic blush development subsystem in electrophotography.
Hiroyuki Kawamoto, Nobuyuki Nakayama, Satoshi Yamada, "Resonance Frequency and Stiffness of Magnetic Bead Chain in Magnetic Field" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP18), 2002, pp 28 - 35, https://doi.org/10.2352/ISSN.2169-4451.2002.18.1.art00009_1