VIBRATION AND DAMPING CHARACTERISTICS OF CYLINDRICAL SHELLS WITH ACTIVE CONSTRAINED LAYER DAMPING TREATMENTS UNDER PARAMETRIC VARIATIONS

Passive constrained layer damping (PCLD) treatments have been regarded as effective means to suppress vibration and sound radiation from various structures. Active Constrained Layer Damping (ACLD) treatments are developed to enhance energy dissipation characteristics of conventional PCLD treatments. In this paper, the application of ACLD treatments is extended to the vibration control of cylindrical shells. The governing equation of motion of cylindrical shells partially treated with ACLD treatments is derived on the basis of the constitutive equations of elastic, piezoelectric, visco-elastic materials and energy approach. The damping of visco-elastic layer is modeled by the complex modulus formula. A finite element model is developed to describe and predict the vibration characteristics of cylindrical shells with partially treated with ACLD treatments. A close-loop control system based on displacement and velocity feedback is considered. The dynamic behaviors of cylindrical shells with ACLD treatments such as nature frequencies and responses in frequency domain are further investigated. The effects of several key parameters such as location and coverage of ACLD treatment on vibration suppression of cylindrical shells with ACLD treatment are also discussed. The numerical results indicate the validity of the finite element model and the control strategy approach. The potential of ACLD treatments in controlling vibration and sound radiation of cylindrical shells as the major critical structures such as cabins of aircrafts, hulls of submarines and bodies of rockets and missiles is thus demonstrated.