Abstract: A new method is presented which is based on the Hilbert transformation of ultrasonic backscattered echo signals from defective materials. During the process the detected echoes can provide a lot of information, such as instantaneous frequency and amplitude. An uneqivocal quantitative relationship between the instantaneous frequency and material characterization is discussed from the theory to the practice. The instantaneous frequency can be used to estimate material propreties because of the behaviour of the scattered waves and the interference effects.
A simulative result and some experimental results are presented, it will be helpful for the further development and application of NDT and NDE in industry.