SU1441297A1 - Method of ultrasonic inspection of materials - Google Patents

Abstract

The invention relates to non-destructive acoustic testing and can be used to control materials in construction and other industries. The purpose of the invention is to increase the reliability of the control by taking into account the dependence of the transmission coefficient of ultrasound in the material on the presence of cracks in it and the size of their opening. In the proposed method, the dependence of the coefficient of ultrasound through the sample on the amplitude of the emitted ultrasonic wave is determined, and abrupt increases in the coefficient of transmission of ultrasound, which are judged on the presence of cracks and the magnitude of their opening, are revealed. 3 il.

Description

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The invention relates to non-destructive acoustic testing and can be used to control materials in building and other industrial areas.

The purpose of the invention is to increase the reliability and informativeness of the control by taking into account the dependence of the cooling coefficient of ultrasound in the material on the presence of cracks in it and the extent of their opening.

FIG. 1 is a block diagram of a device for ultrasonic testing of materials; FIG. 2 and 3 - the dependence of the ultrasound transmission coefficient on the amplitude of the emitted ultrasonic wave, respectively, for samples with one and three cracks,

The device contains series-connected excitation pulse generator 1 and radiating electroacoustic converter 2, the first peak voltmeter 3, the input of which is connected to the output of the excitation pulse generator 1, the receiving electroacoustic converter 4 and the second peak voltmeter 5, connected to the receiving electroacoustic pulse to converter 4e connected in series an adjustable amplifier 65 whose output is connected to a BTopof-i peak-1 5 voltmeter 5s comparison unit 7, the second input of which is connected En to the output of the generator 1 excitation pulses, and the detector 8 defects. In addition, the drawing shows the test sample 9. with a crack 10,

The method is carried out as follows.

The pulse generator 1 excites the electroacoustic transducer 2, which emits into the sample under study t -. {Pulse acoustic signals. The signals passed through the object are delivered by an electro-acoustic transducer 4 and amplified by an amplifier 6. The amplitude of the ultrasonic waves transmitted through the sample and transmitted through the sample is measured using a first peak voltmeter 3 and a second peak voltmeter 5. These measurements are carried out in the process of a monotonous increase in the amplitude of the ultrasonic wave emitted into the sample, and the dependence of the coefficient of transmission of the ultrasound is determined.

The development of the amplitude of the emitted ultrasonic wave. By the abrupt increase in the transmission coefficient of ultrasound, the presence of a crack in the material sample is judged, and from the amplitude of the emitted ultrasonic wave corresponding to the abrupt increase in the transmission coefficient, the value for opening the crack is judged. The size of crack opening (d) is calculated by the formula

. - A.r -.- S

where A is the amplitude of the emitted ultrasonic wave; o is the attenuation coefficient of ultrasound in the sample; 1e is the distance from the point of excitation of the ultrasonic wave in the sample to the crack

With the help of the comparison unit 7 and the defect detector 8, the automatic detection of defective samples can be carried out.

Example. In order to detect cracks in a controlled object, it is acoustically sounding and the ultrasonic wave transmission coefficient D is determined with a monotonic increase in the amplitude of the ultrasound wave emitted into the sample. Get the dependence of D f (AC). An example of such a dependency for a single-crack object is shown in FIG. 2. On the chart you can select three sections.

Section 1. The transmission coefficient D does not depend on the amplitude A c of the ultrasonic wave emitted into the sample. The value is significantly less than the value of the coefficient of passage for the undisturbed object D.

Conclusion. The controlled object contains a defect (s). Reliably determine the nature of the defect and its parameters is difficult.

Section 2. The coefficient D increases sharply with increasing amplitude Aq.

The output of the supervised object contains a defect in the form of a crack. I

The increase in the transmission coefficient D is due to the change in the mechanism for the transfer of the energy of an acoustic wave through a crack at amplitudes of oscillations commensurate with the value of crack opening. In this case, the energy is transmitted mainly not through the crack filler, but directly

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Claims (1)

The method of ultrasonic testing of • materials, namely, that an ultrasonic wave is emitted into a material sample, a wave passed through the controlled sample is measured, the amplitude of the emitted and received ultrasonic waves is measured, and the ultrasound transmission coefficient through the sample is determined by which a crack is detected I with the fact that, in order to increase reliability and informative control, monotonically increasing amplitude of the radiated B Turning ¹ sample was determined by the ultrasonic wave and the dependence of the coefficient pr walking on the amplitude of ultrasound emitted ultrasonic waves, the presence of cracks is judged by the abrupt increase of the transmission coefficient of ultrasound, and the amplitude of the radiated ultrasonic wave corresponding to an abrupt increase in the coefficient of transmission of ultrasound, is judged on the magnitude of the crack opening.