Rahul Sharma, Hartaj, Harinder Pal and S. R. Dutta
A great difficulty is faced in the design of such structures due to the fact that the reduction in weight results in low rigidity and reduced vibration characteristics. Apart from the vibration is effectively controlled; it may destabilize the system and may, very often, result in complete failure of the system. Several advanced applications, such as those in jet fighters, automobiles and spacecrafts, require structures that are highly strong, lightweight and possess high structural damping property. Consequently, there is need to develop structures that are equipped with suitable vibration control. In modern vibration controller design for smart structures, much effort is devoted to the development of an efficient actuator along with high-performance control algorithms. Smart materials such as PZT, terfenol-D, ER, MR, and shape memory alloys have been exploited as candidates for actuators. In the present work, damping is obtained by the electromagnetic force which is generated by the movement of a conducting material through a stationary magnet or the movement of a magnet through a stationary conducting material. This causes ‘‘eddy’’ currents to flow in the conductor. These currents dissipate energy as they flow through the resistance of the conductor. The use of eddy currents for damping of dynamic systems has been known for decades and its application to magnetic braking systems and lateral vibration control of rotating machinery has been thoroughly investigated. Practically, it is unfeasible to prevent the vibration but it can possible to controlled and optimize the vibration up to certain limits.
