Stiffness and damping characterization of ferrofluid seals on the new loudspeaker design

Marcos Pinho (1) , Jean-Michel Génevaux (1) , Bruno Brouard (1) , Nicolas Dauchez (2) , Guy Lemarquand (1)

1 LAUM - Laboratoire d'Acoustique de l'Université du Mans
2 LISMMA - Laboratoire d'Ingénierie des Systèmes Mécaniques et des MAtériaux

The aim of this paper is to determine experimentally the behavior of the ferrofluid seals used in loudspeaker having no viscoelastic suspensions [1]. In this case, the ferrofluid is saturated by a strong magnetic field (300-500 kA/m) relatively to its magnetization (9-32 kA/m). Two parameters are investigated: the radial stiffness that centers the moving part and the axial damping influencing the dynamic response of the loudspeaker. These parameters are measured as function of ferrofluid volume, magnetization, viscosity, shear rate and frequency of oscillation. The behavior is found coherent with the results of literature for relatively weak magnetic fields.

Mots clés: Haut-parleur; Joint ferrofluide; Rigidité radiale; Dissipation axiale

Domaines: Acoustique [physics.class-ph]; Acoustique [physics.class-ph]

Marcos Pinho, Jean-Michel Génevaux, Bruno Brouard, Nicolas Dauchez, Guy Lemarquand. Stiffness and damping characterization of ferrofluid seals on the new loudspeaker design. 10ème Congrès Français d'Acoustique, Apr 2010, Lyon, France. ⟨hal-00539766⟩