Potential and Limitations of a Deconvolution Approach for Guided Wave Structural Health Monitoring

Ultrasonic guided waves offer the possibility of inspecting large areas of structures from a small number of sensor positions. However, inspection of complex structures is difficult as the reflections from different features overlap. Estimating the number and amplitude of the wave packets in ultrasonic time traces is crucial for the development of a guided wave inspection system, in order to detect and locate damage. Deconvolution has been extensively used in geophysical applications to resolve overlapping echoes in the recorded signals. The main objective of this work was to evaluate the applicability of the deconvolution approach for enhancing the resolution of ultrasonic time traces in structural health monitoring (SHM). Numerical simulations on strongly overlapping signals were carried out to evaluate the performance of the two techniques that have been considered: (i) Wiener filter, (ii) single most likely replacement. It was shown that the relatively narrow bandwidth of the input signals and phase shifts between different reflections limit the benefits obtained from deconvolution and it was concluded that deconvolution is unlikely to be useful for guided wave SHM applications.