Ž . Materials and Design 23 2002 277286 Interaction of active and passive vibration control of laminated composite beams with piezoceramic sensorsactuators Young Kyu Kang, Hyun Chul Park, Jaehwan Kim  , Seung-Bok Choi Department of Mechanical Engineering, Inha Uni  ersity, Yonghyun-dong, Incheon 402-751, South Korea Received 6 October 2000; accepted 17 September 2001 Abstract The interaction between active and passive vibration control characteristics was investigated numerically and verified experimentally for carbonepoxy laminated composite beams with a collocated piezoceramic sensor and actuator. The finite element method was used for the analysis of dynamic characteristics of the laminated composite beams. Damping and stiffness of adhesive and piezoceramic layers were taken into account in the finite element modeling. The optimal control theory was applied for the analysis of control characteristics of the beam. Experiments on the active vibration control of the laminated composite beams were carried out using velocity feedback control. The effect of varying the stacking sequence of the laminated composite beam on the active and passive damping properties was studied. The finite element analysis was verified by comparing the Ž . Ž . experimental results in terms of active and passive damping ratios  and modal dampings 2  as well as fundamental frequency. When the gain in velocity feedback control is small, the active control follows the trend of the passive control, but provides additional effects due to the active control. For a large feedback gain, the active control is dominant over the passive control. Active control is more effective in the structure with higher bending stiffness than in the structure with lower bending stiffness when the feedback gain is large.  2002 Elsevier Science Ltd. All rights reserved. Keywords: Composite beams; Finite element modeling; Activepassive dampings 1. Introduction The methodology for vibration suppression of struc- tures can be categorized into two groups, namely pas- sive and active controls. In passive control, the material properties of structure such as damping and stiffness are modified so as to change the response of structure. A typical example of passive control is tailoring of composite materials. A lot of research on tailoring of  Corresponding author. Tel.: 82-32-860-7326; fax: 82-32-868- 1716. Ž . E-mail address: jaehwan@inha.ac.kr J. Kim . the composite material has been carried out actively in terms of the effect of fiber orientation on stiffness,   strength and damping ratio 1  4. In active control, the structural response is con- trolled by adding external effort to the structure. Al- though active control requires the system to be com- plex and expensive, it can achieve a good vibration suppression performance in comparison with passive control. To sense and control structural response ac- tively, a smart material, such as piezoceramic material  5 is frequently bonded onto the surface of a structure or embedded in it. Depending on the applied voltage, electromechanical coupling of the forcing transducer to the structure, and the location of the piezoelectric 0261-306902$ - see front matter  2002 Elsevier Science Ltd. All rights reserved. Ž . PII: S 0 2 6 1 - 3 0 6 9 01 00081-4