A study on the efficacy of modal acoustic emission technique for health monitoring of structures with different geometries

Health monitoring of structures is a fertile field of research. Different techniques are being developed through research to perform the health monitoring on different types of structures. Acoustic emission (AE) technique is considered to be promising, as this technique can be used for damage detection in real time. However, AE technique has some limitations as far as geometry of structure is concerned. Here in this study, modal AE (MAE) technique has been explored through experimental investigation in laboratory for its possible, effective applications in the health monitoring of structures with different geometries, namely, plates and truss. MAE technique is adopted as it facilitates an analysis of structural behaviour under the application of an AE source along with source localisation. Further, a methodology is proposed to minimise the effects of geometry and boundaries/edges. The methodology is based on identifying the front part of the time-frequency representation (TFR) diagram, i.e. first few energetic zones in the TFR, of an AE signal, followed by the alignment of these zones with respect to the contour of the group velocity curves of Lamb modes. The efficacy of the proposed method for damage localisation has been verified and found to be promising.