Potential of FBG sensors for vibration control in smart structures

The large use of lightweight structures has emphasized the need to reduce undesired vibrations which can compromise the integrity and the safety of flexible structures. The advancements in materials technology have made available a new generation of materials regarded as smart. Thanks to the results obtained in this field, many research are focusing on the study of intelligent structures, able to modify their mechanical properties. Composite materials are interesting in the construction of smart structures, thanks to their high mechanical properties which allow to obtain lightweight structures with high resistance and due to the possibility of embedding sensors and actuators inside the structure. Among all, optical fiber sensors are widely used in the development of smart structures. However, while they are usually considered for structural health monitoring, this paper proposes their use in active control application. A structure made of carbon fiber with Fiber Bragg Grating (FBG) sensors and piezoelectric actuators is able to self-sense its state of vibration and to provide control forces to reduce it. The peculiarity of this structure is represented by the possibility to monitor a large number of sensors (to approximate distributed measurements), suitable for physical feedback or modal control. The experimental tests carried out allow to investigate the effectiveness of these setup in the active vibration control and to evaluate the limits of this technology.