Active damping in structures

The modern trend toward lighter and more flexible structural designs brings with it increasing demands for ways and means of dissipating excess energy transferred to such structures by the action of dynamic external forces. The present study concerns the use of active feedback control mechanisms as a means of damping out excess vibrations. The basic active damping scheme involves the introduction of a control force on the structure through a feedback network whose input is dictated by the motion of the structure. The feedback network is composed of a sensor, an electro-hydraulic servo-mechanism and a forcer, and its action in connection with a simple spring-mass system is studied. In all nine different control schemes are investigated and their relative merits discussed. An application of the active damping concept is worked out in the Appendix. Starting in 1946 as the College of Aeronautics, the Cranfield Institute of Technology was granted university status in 1969. In 1993 it changed its name to Cranfield University.