Distributed actuation characteristics of clamped-free conical shells using diagonal piezoelectric actuators

In spacecraft, severe vibrations induced by the launch vehicle may cause damage to the precision payload. Therefore active adapters with vibration suspending characteristics are needed. This paper presents theoretical studies of the active vibration control characteristics of conical shells with laminated piezoelectric actuators. A diagonal piezoelectric actuator is proposed to control the axial, lateral and transverse vibrations of the conical shell. Modal functions are designed to represent the free vibrations of the conical shell with clamped-free boundary conditions. General formulae of the modal control force and corresponding components are derived based on the converse piezoelectric effects and then specified for the diagonal actuators. By using an open-loop control method, the modal control characteristics of diagonal actuator segments at different locations are investigated and compared, and the axial, lateral and transverse vibrations of two conical shell models are evaluated. The optimal locations of actuator segments for the control of different natural modes are also investigated.