Guided waves modes identification in pipes detection by application of the matching pursuit method

Guided waves have the multi-modes and dispersive characteristic and the mode conversion at boundary or with defects in pipes, which make it very difficult to identify different guided waves mode reflection signals in pipes detection. The experiment method is using guided waves to detect two stainless steel pipes, one pipe has no defect and another pipe has a hole defect. The guided waves detection echo signals are obtained. By calculating the Chirplet match atom parameters and the time frequency distributions spectrum of guided waves detection echo signals, guided waves mode with T(0,1),F(1,2) and L(0,2) are respectively identified for no defect pipe detection, and defect echo consisted by two wave-packets with T(0,1) and F(1,2) mode is also identified for defect pipe detection. The results show that the matching pursuit method has a tremendous advantage to identify different guided waves modes signals in pipes non-destructive testing.