INFLUENCE OF BOUNDARY CONDITION ON THE BEAM PVDF MODAL SENSOR DESIGN

PVDF can be used as the distributed error sensors in the active control of sound and vibration, and most of current research is focus on classical boundary conditions, while the absolutely ideal boundary is very little. In this paper, the design of a PVDF modal sensor with flexural boundary conditions is investigated. Based on a boundary smoothed Fourier series, the output signal of the PVDF modal sensor is directly proportional to the target structural mode amplitude. By applied Rayleigh-Ritz procedure into the Lagrangian equation of a flexible beam structure, the shape function and its second order derivatives are obtained. Numerical results are then presented to show that there is a boundary stiffness influence zone for the PVDF modal shape, in which the shape varies rapidly. This work can shed some light to the PVDF sensor design of flexible structure, especially with complicated boundary conditions.