an apparatus for controlling vibration in a structural element includes a first magnet attached to the structural element , a sensing device positioned to detect motion of the structural element , and a vibration control device connected to receive information from the sensing device concerning motion of the structural element . the vibration control device includes a second magnet spaced apart from the first magnet and a coil for varying the magnetic field between the first magnet and the second magnet . the coil , in response to signals from the sensing device , alters the strength of the magnetic field and thereby controls vibration of the structural element .