Inman D., Tarazaga P., Salehian A.

Modern structures are often driven by design constraints to be extremely lightweight and hence very flexible and subject to increased vibration problems. In addition, improved manufacturing techniques often produce very good joints in structures reducing the amount of natural damping in structures. For instance, removing welds in bladed disc assemblies caused increase blade fatigue because of the reduced damping. As a result, active and passive damping methods are increasingly in demand. Here the basic areas of passive and active damping are reviewed and compared. Emphasis is placed on damping treatments, smart materials and applications to large flexible (inflated) space structures and automobile components. Passive methods discussed include a summary of standard constrained layer damping treatments and piezoelectric based shunt dampers with focus on the various modeling methods and comparisons. Active methods focus on those that are obtained by using piezoelectric based materials: films, ceramics, and composites, as the sensor and actuation devices. The main example consists of a 300 meter/ 552 kg inflated satellite proposed for flight in the next 10 years called the Innovative Space Based Radar Antenna Technology (ISAT) program. This truss like structure holds a radar platform and is intended to rotate around its mid point for surveying the earth's surface. The rotation along with other maneuvering forces potentially causes large vibration interfering with the satellites ability to take measurements. Hence, active vibration means are required to remove these unwanted vibrations. Theoretical and numerical results are presented along with experimental validations of the modeling and vibration suppression methods.