Identification of delamination in a composite beam using integrated piezoelectric sensor/actuator layer

A sensor charge output deviation method for delamination detection using isolated piezoelectric actuator and sensor patches

“…e 31a , e 31s ) is chosen to be À9.9 C/m 2 . The density for the host beam, PZT sensor or actuator and adhesive layers are selected to be 1521.4, 7800 and 1600 kg/m 3 , respectively [14,16,17]. The stiffness of the gridding electrode is neglected owing to their small size relative to those for the laminated beam, PZT sensor and actuators.…”

“…It was noted from the research previously conducted by authors [12][13][14] that the piezoelectric sensor can only effectively identify the size and location of a delamination which is beneath the sensor. Therefore, in order to cost-effectively detect delaminations embedded within a large laminated composite structure, it is suggested to bond piezoelectric sensors on the surface of the composite segment where delaminations are expected to most likely develop.…”

“…However, this method is limited to graphite fibre reinforced plastics composites. Recently, the present authors developed several dynamics analytical models for identification of a delamination embedded in a laminated composite beam [12][13][14]. The presence, size and axial location of a delamination were identified on the basis of monitoring the sensor charge output (SCO) distribution along the beam length for the first three order frequencies, when the host beam was excited externally or by an actuator.…”

Surface strain distribution method for delamination detection using piezoelectric actuators and sensors

“…Figure 6 depicts the case for mode 1 of specimen A. strip number 10) to form a complete SCO distribution for this case. The constructed sensor charge output distributions are smoother and have enhanced repeatability compared to those obtained using previous sampling method [15][16][17]. Table 1 lists the average values and their standard deviations of the first three frequencies for all specimens measured repetitively 10 times.…”

“…We modified the method of recording the sensor signal previously used [15][16][17] by reading sensor signal of multiple continuous points in one test rather than one point only in one test. Because only 6 channels of the sensor signal conditioner were available, three sets of tests were required to completely measure one sensor charge output distribution for each specimen corresponding to one vibration mode, and each set of test was repeated 10 times in order to obtain average signal.…”