Active vibration controls are helpful in improving fatigue life of structures through limitation of absolute displacements. However, control algorithms are usually designed without explicitly taking into account the fatigue phenomenon. In this paper, an adaptive vibration controller is proposed to increase the fatigue life of a smart structure made of composite material and actuated with piezoelectric patches. The main innovation with respect to the most common solutions is that the control laws are directly linked to a damage driving force, which is correlated to a fatigue damage model for the specific material. The control logic is different depending on the damage state of the structure. If no significant damage affects the structure, the controller decreases the crack nucleation probability by limiting the driving forces in the overall structure. On the contrary, if initiated cracks are present, their further propagation is prevented by controlling the damage driving forces in the already damaged areas. The structural diagnostics is performed through a vibration-based health monitoring technique, while periodical adaptation of the controller is adopted to consider damage-induced changes on the structure state-space model and to give emphasis to the most excited modes. The control algorithm has been numerically validated on the finite element model of a cantilever plate.

Date Published: 2 April 2015
PDF: 9 pages
Proc. SPIE 9431, Active and Passive Smart Structures and Integrated Systems 2015, 94312P (2 April 2015); doi: 10.1117/12.2084159

Published in SPIE Proceedings Vol. 9431:
Active and Passive Smart Structures and Integrated Systems 2015
Wei-Hsin Liao, Editor(s)