Detection of delamination defects in carbon fiber reinforced polymer components: Miniaturized hardware design for the smart material actuation of ultrasound guided waves

This contribution is concerned with the hardware design of a structural health monitoring (SHM) system for continuous delamination detection in carbon fiber reinforced polymer components. The component is equipped with an integrated actuator array of eight piezoelectric patches which are driven by miniaturized high frequency power amplifiers. The phased line array is capable of emitting directional guided Lamb waves with a frequency of several hundreds of kilohertz and with user-selectable waveform pattern and directivity angle into the continuum. The directivity of the Lamb wave depends on the phase difference between the individual actuator signals. A special milling technique allows to create phased array stripes of arbitrary size and shape of the electrodes with high precision and reduce the placing and time complexity. A laser scanning Doppler vibrometer is used to visualize the propagation of the corresponding Lamb waves, as well as reflections which are caused by delamination defects. The results of the measurements can be evaluated to characterize the damage and the material properties. The hardware platform provides a portable system for the investigation of real world components, e. g. aircraft CFRP structures.