Electromechanical impedance based debond localisation in a composite sandwich structure

An electromechanical impedance (EMI) based structural health monitoring (SHM) approach is proposed for the localisation of skin-core debonds in composite sandwich structure (CSS). Towards this, laboratory experiments and numerical simulations of EMI in a CSS with core to bottom face-sheet debond have been carried out using a network of piezoelectric transducers (PZTs). The frequency-domain analysis of the registered EMI signals shows that the presence of inter-facial debonds in the CSS significantly influences the conductance magnitudes of the registered EMI data. It was also noticed that the conductance magnitudes of the signals are dependent on the debond-to-PZT distances. In all the study cases, an agreement between the simulation and experimental results is observed. Eventually, a simulated SHM approach is proposed that uses a debond detection algorithm to calculate the changes in conductance magnitudes to effectively locate such debonds in CSS. The study is further extended for the detection of debonds at different locations in the CSS, including a debond located at the edge to assess the potential of the proposed SHM approach.

Automated summary

A novel electromechanical impedance-based SHM approach is proposed for localizing skin-core debonds in composite sandwich structures. Experimental and numerical studies show that interfacial debonds significantly affect conductance magnitudes of EMI signals in CSS, with magnitude dependence on debond-PZT distances. A simulated SHM approach using a debond detection algorithm effectively locates such debonds, with potential for detecting debonds at different locations in CSS.