Terfenol-D driven flaps for helicopter vibration reduction

• Published in: Smart materials and structures 1996-02, Vol.5 (1), p.49-57
• Main Authors: Fenn, Ralph C, Downer, James R, Bushko, Dariusz A, Gondhalekar, Vijay, Ham, Norman D
• Format: Article
• Language: English
• ISSN: 0964-1726; 1361-665X
• DOI: 10.1088/0964-1726/5/1/006

The utility of helicopter aviation is limited by the high vibration levels caused by the interaction of each rotor blade with the wake of preceding blades. Existing full-blade actuation using a swashplate has various problems, such as insufficient bandwidth, limitations in the number of harmonics controlled, high maintenance, and lack of spanwise lift variation. These problems are avoided by the proposed flap-operated individual blade control system which uses magnetostrictive actuation technology. Terfenol-D actuation has many advantages over competing technologies, such as hydraulic systems, electric motors, and piezoelectric elements. These benefits include all-electric operation, simplicity and reliability, low mass, low voltage, and insensitivity to centripetal acceleration. A blade mounted Terfenol-D actuator was developed for the high-weight-penalty helicopter application. The optimum coil to Terfenol-D volume ratio was derived that gives the highest mechanical power output for a small actuator envelope and mass. The magnetostrictive actuation system will weigh less than 1 percent of gross vehicle weight and use only 0.7 percent of cruise power. (Author)