High Power Density Magnetostrictive Reaction-Mass Actuator

Magnetostrictive materials have been successfully used in single-axis actuator designs to produce forces over 3500 pounds, strains of 1200 ppm, and have bandwidths past 10,000 Hertz. Terfenol-D, the "giant strain" magnetostrictive material is an excellent candidate to produce a high power density reaction-mass actuator for helicopter gearbox noise cancellation. Using magnetostrictives, the single axis actuator can meet the weight, volume and durability requirements, without compromising the force or freuency range specifications. In contrast to piezoelectric materials, magnetostrictive materials have seven times larger strain and fifteen times higher energy density, resulting in more actuation effort for the given mass and volume budget. Unlike piezoelectrics, magnetostrictives do not require high voltages to operate efficiently. Compared with piezoelectrics, magnetostrictives have greater reliability and longer life advantages. The proposed work is to demonstrate the feasibility of using a magnetostrictive driven reaction-mass actuator for helicopter gearbox noise cancellation. During Phase I, the objective is to design, fabricate, test, and deliver a high-force density, magnetostrictive-based reaction-mass actuator. This actuator shall be capable of exceeding the suggested specifications of over 100 pounds at frequencies between 1000 and 4000 Hz. During Phase II, this work will be extended to multi-degree-of-freedom designs.