Delamination Detection of Composite Beams Using Piezoelectric Sensors with Evenly Distributed Electrode Strips

Abstract

In this paper, a new analytical model is presented to detect the presence, size, and location of a delamination embedded in a laminated composite beam. The sensors bonded on the top and bottom surfaces of a host beam are made from PZT piezoelectric layers. By employing this analytical model, the first three natural frequencies and sensor charge output distribution for the beams with different delamination length, axial and through-the-thickness delamination location, and delamination gap can be predicted, when a beam is excited by an external force. An approach is also proposed to obtain the sensor charge output distribution along the beam length using evenly distributed electrode strips. Subsequently, the present model is applied to a laminated plain weave composite beam with an embedded and through-width delamination, followed by an extensive numerical study. An investigation is carried out on the influence of the boundary condition, delamination length, axial delamination location, through-the-thickness delamination location, delamination gap on the first three natural frequency change and sensor charge output distribution along the beam length. The effects of number and size of electrode strips on the sensor charge output distribution is also studied. A comparison of the first three natural frequencies between the present predicted and finite element analysis results reveals that there is a good agreement between these two models.