Damage Identification Based on the Nodal Line Active Modulation Method

Abstract

A novel vibration-based method (VBM) for damage identification named nodal line active modulation (NLAM) is proposed in this study. Unlike traditional VBMs, NLAM can identify damage by taking advantage of the nodal line effect, which is observed when the defect is located on the nodal lines. In these cases, the dynamic responses of the structure remain nearly unchanged. Through numerical studies, we have elaborated on the theory in detail and painted a clearer picture of the steps in the NLAM process through a cleft detection in an aluminum plate. In experimental research, piezoelectric transducers work as both actuators and sensors for intact and damaged carbon fiber reinforced plastic laminates, while a scanning laser Doppler vibrometer measures the full-field response for the intact structure only. The added mass 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 should provide practical applications for structural health monitoring.