A magnetostrictive water pump using Terfenol-D has been designed and built, achieving a flow rate of 15mi/sec at 5 psi, using 41 watts. This is a higher flow rate and lower pressure than previous magnetostrictive pumps. The pump is 6" long and 3.6' in diameter. A model ofpump performance has been developed, including valve inertia which limits the drive frequency, and trapped air in the chamber, which can reduce the flow rate and make the pump noisy. Methods have been developed to eliminate trapped air. The pump uses a hydraulic stroke amplifier, which turned out much stiffer axially than it was designed to be. This has adversely affected pump performance, because of fmite Terfenol compliance and fmite housing compliance. With a stroke amplifier of optimal stiffness, and with better quality Terfenol, the pump should be able to achieve a flow rate of 30 mllsec at 5 psi, consuming 25 to 35 watts. Although the power is more than would be needed by a piezoelectric pump of the same performance, a Terfenol-D actuator offers important advantages, including low voltage and no known fatigue mechanism. Furthermore, much ofthe modeling would be relevant to a piezoelectric pump as well.
A magnetostrictive reaction mass actuator possessing a large force to weight ratio has recently been developed at SatCon Technology Corporation. Achieving such high performance requires adequate modeling of this multidisciplinary device. The developed models allow performance optimization to be accomplished through parameter selection and control design.At the 1996 smart materials conference, the modeling and design issues associated with this actuator were discussed. Since that time, additional experiments and optimization have been performed that validate the proposed modeling. These experiments include validation of the thermal modeling and dynamic model validation through control experimentation. In addition to these results, a discussion of the trade-offs in terms of eddy current, controller, and thermal requirements, will be presented.
A magnetostrictive wire-bonding clamp for use in semiconductor packaging applications has been developed by Mechatronic Technology Co. Semiconductor industry trends, requiring high process throughput on increasing lead count packages, make the magnetostrictive material Terfenol-D a candidate for this application. To construct this small, lightweight device, small samples of Terfenol-D were prepared by ETREMA Products, Inc. This paper reports the initial design, mathematical modeling, and experiments related to this initial prototype.
Magnetostrictive materials often rely on magnetic fields generated through the use of a solenoidal coil. However, the field-generating coil also acts as a source of heat causing thermally induced strains in the magnetostrictive drive element. To insure that the useful magnetostrictive strains are large in comparison with the thermally induced strains, the solenoid may be optimized. This paper presents a simple one dimensional (1-D) magnetic model useful for predicting the magnetic field inside the magnetostrictive drive rod. The advantage of this model is that it can be evaluated very quickly, making it well suited for use in optimization algorithms. A figure of merit is presented that weighs the energy stored in the coil against the power that must be dissipated to maintain the field. With the magnetic model and cost function, the solenoid may be sized to maximize the volume averaged field in the magnetostrictive element per unit of volume averaged dissipated heat in the solenoidal coil. While previous work addressed field/power optimization at the center of air-cored solenoids, the work presented here considers optimization of the average field along a rod of permeable magnetostrictive material. The results indicate that coil quality decreases rapidly if the coil is thinner than optimal, but decreases rather slowly for a thicker than optimal coil.
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