Damage Identification Based on the Nodal Line Active Modulation Method

A novel vibration-based method (VBM) for damage identification, nodal line active modulation (NLAM), is proposed in this study. Unlike traditional VBMs, the NLAM can identify damage by taking advantage of the nodal line effect, which is that when a defect is located on the nodal lines, the dynamic responses of the structure remain nearly unchanged. The basic idea of NLAM is introduced through a simply supported beam. In numerical study, we have discussed the detection steps of the method in detail by detecting a cleft detection in an aluminum plate. In experimental research, piezoelectric transducers work as both actuators and sensors for an added mass damaged detection in carbon fiber reinforced plastic laminates, while a scanning laser Doppler vibrometer is employed for measuring the full-field dynamic response. The damage is visualized from the highlighted nodal lines of the modulated operational deflection shapes. The present investigation provides a new idea for VBM damage detection, which will have practical applications for structural health monitoring.