Low-velocity impact damage detection of CFRP composite panel based on Transfer Impedance approach to Structural Health Monitoring

In the paper the so called Transfer Impedance approach to low-velocity impact damage detection of composite structure is presented. The approach is based on application of PZT transducers for excitation and acquisition of elastic waves in a CFRP (Carbon Fiber Reinforced Polymer) composite panel. The method relies on the so called pitch - catch scheme of PZT transducers application, where pairs of sensors are used for the purpose of structure monitoring, i.e. one sensor is used as elastic waves generator and the other as receiver of excited waves. In the presented paper, sinusoid signal in a given frequency range is used for elastic waves excitation, which is different than in the standard pitch-catch approach. In the paper algorithm for signal analysis is presented, which allows to maintain full information carried by acquired signals in a given frequency for the purpose of damage detection. Stability of damage indication acquired for different pairs of PZT transducers of the network is analyzed in the paper as well as sensitivity of the approach to impact damage detection. Detailed description of the developed method, hardware implementation, experimental setup as well as description of the obtained results are delivered in the paper.