Damping effects of magnetic fluids of various saturation magnetization (abstract)
| Autor: | Mark S. Chagnon |
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| Rok vydání: | 1990 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 67:5477-5477 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.345854 |
| Popis: | Magnetic fluids have been widely accepted for use in loudspeaker voice coil gaps as viscous dampers and liquid coolants. When applied properly to a voice coil in manufacturing of the loudspeaker, dramatic improvement in frequency response and power handling is observed. Over the past decade, a great deal of study has been given to the effects of damping as a function of fluid viscosity. It is known that the apparent viscosity of a magnetic fluid increases as a function of applied magnetic field, and that the viscosity versus field relationship approximate that of the magnetization versus applied field. At applied magnetic field strength sufficient to cause magnetic saturation of the fluid, no further increase in viscosity with increased magnetic field is observed. In order to provide a better understanding of the second order magnetoviscous damping effects in magnetic fluids used in voice coils and to provide a better loudspeaker design criterion using magnetic fluids, we have studied the effect on damping of several magnetic fluids of the same O field viscosity and of varying saturation magnetization. Magnetic fluids with saturation magnetization ranging from 50 to 450 G and 100 cps viscosity at O applied field were injected into the voice coil gap of a standard midrange loudspeaker. The frequency response over the entire dynamic range of the speaker was measured. The changes in frequency response versus fluid magnetization are reported. |
| Databáze: | OpenAIRE |
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