Attaining a controlled output strain and utilizing a full potential of active material are the significant factors to design Terfenol-D actuator devises such as active damping devices, high speed hydraulic valve actuators, large-force linear motors and large torque rotating motors. To achieve this, a high magnetic biasing field is required in an actuator. The present work attempts to propose a suitable layout in a Terfenol-D actuator based on numerical magnetic field analysis. Three configurations namely single coil, coaxial coils and coil with permanent magnet combinations that surrounds the Terfenol-D material are considered in the present study. Ansoft package magnetic flux density is used to evaluate the distribution of magnetic flux density of the layouts used in an actuator. Further, the magnetic flux density is evaluated and compared among them to decide the best configuration to be used in a Terfenol-D actuator. Structure and layout of a proposed actuator is outlined. With this, the number of turns required for coaxial coils is computed using Ampere's law and in turn verified the same using the reluctance approach. Finally, it appears that all these results work as well as anticipated and has their individual advantages.

1. . Benbouzid, M. E. H. , Reyne, G. and Meunier, G (1995). "Finite element modeling of magnetostrictive devices: Investigation for the design of the magnetic circuit. " IEEE transaction on Magnetics, 31(3), 1813-1816.
2. . Li, L. , Zhang, C. , Yang, B. and Li, X. (2007). "Finite element analysis of the uniformity magnetic field for on-off giant magnetostrictive actuators. " International Conference on Electrical Machines and Systems (ICEMS), 17-20th October, Wuhan, China, 3758-3761.
3. . Wang, L. , Ye, H. , Liu, Y. T. and Yao, S. M. (2006). "Analysis and optimization for uniformity of magnetic field during the giant magnetostriction. " Journal of Physics, 48, 1336-1340.
4. . Han, H. , Xin, Q. and Wang, S. (2008). "Finite element analysis on magnetic field in the actuator of giant magnetostrictive linear motor with Ansoft. " IEEE International Conference on Industrial Technology, Chengdu, 1-5.
5. . Wang, J. , Li, G. , Wang, C. and Liu, C. (2011a). "Finite element analysis of internal magnetic field on Terfenol-D rod in high frequency driven. " International Conference on Artificial Intelligence, Management Science and Electronic Commerce, 5572-5575.
6. . Wang, C. , Wang, J. and Li, G. (2011b). "Finite element analysis of internal stress and strain on Terfenol-D rod in high frequency driven. " International Conference on Artificial Intelligence, Management Science and Electronic Commerce, 5576-5579.
7. . Wakiwaka, H. , Umezawa, T. and Yamada, H. (1993). "Improvement of flux density uniformity in giant magnetostrictive material for acoustic vibration element. " Proceedings of IEEE, Transaction on Magnetics, Nagano, Japan, 29(6), 2443-2445.
8. . Sung, B. J. , Lee, E. W. and Lee, J. G. (2007). "A design method of solenoid actuator using empirical design coefficients and optimization technique. " IEEE International Conference on Electric Machines and Drives, 1, 279-284.
9. . Dehui, L. , Quanguo, L. and Yuyun, Z. (2008). "Magnetic circuit optimization design of Giant magnetostricitve actuator. " 9th International Conference Computer-Aided Industrial and Conceptual Design (CAID/CD), 22-25th November, Kunming, 688-692.
10. . Bansevicius, R. and Virbalis, J. A. (2008). "Investigation of magnetic circuit permanent magnet-Terfenol-D-Air. " Electronics and Electrical Engineering, 86, 1-6.
11. . Lu, Q. , Jing, C. , Min, Z. and Dingfang, C. (2010). "Integrated optimized design of GMA with double water-cooling cavums. " International Conference on Mechanic Automation and Control Engineering, 26-28th June, Wuhan, 3562-3565.
12. . Olabi, A. G. and Grunwald, A. (2008). "Computation of magnetic field in an actuator. " Simulation Modeling Practice and Theory, 16, 1728-1736.
13. . Engdahl, G. (2000). "Handbook of Giant Magnetostrictive materials," Royal Institute of Technology, Stockholm, Sweden, 1-340.

Terfenol-d Biasing Magnetic Flux Density Ansoft Coaxial Coils Permanent Magnet Ampere's Law Reluctance Approach.