The metrologic fundamentals of Ultrasonic Echo-Amplitude (UEA) defectometry

摘要

The new concept of differential sensitivity of ultrasonic testing was introduced instead of minimum threshold of detection of defects. Moreover, the real defects are replaced by their models in the form of round normal discs, reflecting signals, equivalent to them: amplitude and delay. Process of UEA defectometry takes place in acoustic field of transducer echo-channel. The main its parameters are the field sensitivity (FS) of echo-channel in the form of partial derivative B = ∂q/∂v and three kinds (types) of derivatives from it for each of three independent universal variables of the field (q, u, v), i.e., B_1 = ∂B/∂u, B_2 = ∂B/∂v, B_3 = ∂B/∂q. For FS of echo-signal of each kind their maximums are distinguished and optimum parameters of UEA are determined: position of time window; discreteness of measurement of amplitude of echo-signals and optimum moment for readout of the desired echo-signals in the process of manual scanning.