1pEA9. High-power, low-frequency magnetostrictive TRIPODE and JANUS projectors.

Session: Monday Afternoon, December 2

Time: 4:00


Author: Bertrand Dubus
Location: IEMN, UMR CNRS 9929, Dept. ISEN, 41 boulevard Vauban, 59046 Lille Cedex, France
Author: Patrice Bigotte
Location: IEMN, UMR CNRS 9929, Dept. ISEN, 41 boulevard Vauban, 59046 Lille Cedex, France
Author: Frank Claeyssen
Location: Cedrat-Recherche, ZIRST 4301, 38943 Meylan Cedex, France
Author: Nicolas Lhermet
Location: Cedrat-Recherche, ZIRST 4301, 38943 Meylan Cedex, France
Author: Gilles Grosso
Location: Eramer, ZI du camp Laurent, 83500 La Seyne sur Mer, France
Author: Didier Boucher
Location: DCN-Ingenierie-Sud, DLSM, Le Brusc, 83140 Six Fours les Plages, France

Abstract:

Terfenol-D is a magnetostrictive rare-earth alloy having giant dynamic strain capabilities and low Young's modulus compared to PZT ceramics. Therefore, terfenol-D is a good candidate for realizing high-power, low-frequency projectors for oceanography or sonar. This paper presents two magnetostrictive projectors which have been recently designed and realized for the French Navy. The first one is a tonpilz transducer (TRIPODE) which uses three parallel terfenol-D rods as drivers. Magnetic dc bias and excitation are produced by coils. The drivers are surrounded by a cooling liquid continuously stirred by an electrical device. In water, the maximal acoustical power reaches 4 kW at 1.1 kHz. TRIPODE volume and mass are, respectively, 22 dm[sup 3] and 60 kg. The second one is an axisymmetrical double-ended longitudinal vibrator (JANUS) having a central terfenol-D rod. Permanent magnets provide magnetic dc bias. A specific thermal analysis has been performed to enable heat evacuation by natural convection. Models predict an acoustical power of 1.5 kW at 400 Hz. JANUS volume and mass are, respectively, 25 dm[sup 3] and 100 kg. For both transducers, various results obtained at the design stage during realization and experiments are provided.


ASA 132nd meeting - Hawaii, December 1996