SU1402920A1 - Method of determining characteristics of acoustic piezoelectric transducer - Google Patents

Description

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The invention relates to acoustic measurements and can be used in determining the characteristics of a piezoelectric acoustic.

transducer, in particular when monitoring the performance of ultrasonic transducers used in defectoscopy.

The aim of the invention is to increase productivity and accuracy by determining the parameters of the radiation and receiving transducers at various points on its surface and impersonal filtering of these parameters, 1 The drawing shows a block diagram of the device that implements the method of determining characteristics of the acoustic joezoelectric transducer.

A method for determining the characteristics of an acoustic piezoelectric transducer is as follows.

The transducer is mounted on an acoustic load and energized by the 4th electrical signal. In a plane parallel to the working surface of the converter, the oscillations N passed through the material of the load are measured by acoustic pressure.

p1 (X, y, t) is discrete in time t at k | each point of the receiving plane with the X, Y cofinishes. Then, alternately, pulses of acoustic waves are emitted at each point of the receiving plane with coordinates X, Y, and the transducer receives pulses of these oscillations that have passed through the material of the heater. During the reception, the electric voltage U (X, Y) is discrete in time measured on the converters. If after this, the inverse function and (X, Y, D) and P (X, Y, t) P4 get the distributed transfer functions reception and emission of the controlled converter, and the characteristics of the transformer r4r1 are determined from them.

A device that implements the method of acoustical piezoelectric transducer TFL performance, sequentially connects measuring generator 1, commutator 2, amplitude-time controller 3, buffer memory unit 4, module 5 discrete Fourier transform, memory unit 6, digital inverse filter 7, digital computer 8, for example, microcomputer type

DVK-1 and display unit 9. The device also contains a control unit 10, the output of which is connected to the second inputs of the switch 2, the buffer storage unit 4, the memory unit 6, the digital expander 8 and the display unit 9, and an excitation pulse generator 11 whose output is connected to the third input of the switch 2. In addition to in addition, the device contains an acoustic load 12, made in the form of a thick piezoelectric ceramic plate, whose thickness H is chosen from the condition H ----; f, where C is the velocity ra / Ltf,

acoustic oscillation spaces

the material of the plate, -Cp- the pulse duration at the output of the generator 11. Position 13 on the drawing marked controllable transducer. The diameter of the load plate 12 is chosen to be 2-3.5 times the maximum diameter of the tested transducers 13. On the piezoplate of load 12, there is one electrode connected to the ground bar and located on the side of the working surface of the transducer 13. On the opposite side of the piezo load plate 12 another electrode divided into areas, for example, with dimensions of 1.5 x 1.5 mm at a distance of 1 mm from each other, electrically connected to the remaining inputs of switch 2.

A method for determining the characteristics of an acoustic piezoelectric transducer is implemented as follows. t

The converter is electrically connected to the output of the generator 11 and is installed on an acoustic load 12. The generator 11 excites the test ultrasonic transducer 13, which forms the acoustic field in the load 12. From the load terminals 12, the relief of the acoustic field as a voltage as a function of time in series with Each element of the load 12 through the switch 2 is fed to the amplitude-time quantizer 3, where the analog signal is digitized, and then stored by block 4. The signal is then digitally post falls into the module 5 of the discrete Fourier converter, the output of which is a complex matrix, the values of which are stored by block 6. These values are discrete samples of the slice for emitting the test ultrasound transducer 13 at a given frequency. After that, the switch 2 according to the signal of block 10 sequentially connects the measuring generator 1 to each element of the acoustic load 12, and the output of the converter 13 to the amplitude-time quantizer 3, where the analog signal is digitized. The converted signal is stored by block 4 and subjected to a discrete Fourier transform in module 5, the output of which is another complex matrix, also remembered by block 6. The values of the resulting matrices are subjected to general inverse two-dimensional filtering in filter 7, the output of which receive distributed transfer functions of the converter 13 I

In a digital computer 8 using the mathematical model of the acoustic path of the ultrasonic flaw detector get the necessary secondary characteristics of the transducer 13, for example

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transducer, which increases the control performance by saving measurement time obtained from one installation of the test ultrasound transducer per acoustic load, which is characterized by a stable acoustic contact, reducing the effect of measurement scatter and provides sufficiently high performance monitoring accuracy Ultrasonic piezoelectric transducers.

Claims (1)

15 claims The method of determining the characteristics of an acoustic piez oelectric transducer, which consists in installing the transducer on an acoustic load, excites the transducer with an electric signal 20 25 scrap, take acoustic oscillations passed through the material of the load, measure the parameters of the received oscillations and with their help determine the characteristics of the transducer, which differs with the fact that, in order to improve performance and accuracy, directivity pattern, 30 acoustic oscillation coefficient is produced in the plane parallel to the working surface of the transducer, measures the acoustic pressure discretely in time at each point of the receiving plane, then additionally excites pulses of acoustic oscillations at each point of the receiving plane, receives additional excited pulses during the reception, additionally excited pulses during reception Pulses are measured by an electrical voltage discretely in time on the converter; the measured transmitting functions of reception and radiation are fixed by measured values e audio, which is determined by the characteristics of the transducer. transformations, etc. Measurement and processing results are recorded by block 9, for example, by a printing device, in the form of a passport of a test piezoelectric transducer 13. The recovery error of the distributed transfer functions of radiation and reception according to the measurement of the field cutoff is 0.9, where is the measurement error of the cutoff field, and the error of the calculation of the secondary parameters is 0.99E. Measurement of the primary parameters (distributed transfer functions of radiation and reception) of ultrasonic transducers makes it possible to calculate all the necessary secondary parameters and characteristics of the piezoelectric a transducer that increases the monitoring performance by saving the measurement time obtained from one installation of the tested ultrasound transducer per acoustic load, which is characterized by a stable acoustic contact, reducing the influence of scatter of measurement results and provides a sufficiently high accuracy of monitoring the performance of the ultrasonic piezoelectric transducers . 15 claims The method of determining the characteristics of an acoustic piez oelectric transducer, which consists in installing the transducer on an acoustic load, excites the transducer with an electric signal scrap, take acoustic oscillations past the material of the load, measure the parameters of the received oscillations and use them to determine the characteristics of the converter, characterized in that, in order to improve performance and accuracy, acoustic oscillations are made in the plane parallel to the working surface of the transducer, measures the acoustic pressure discretely in time at each point of the receiving plane, then additionally excites alternately at each point of the reception plane pulses of acoustic oscillations, receives additional excited pulses during the reception, and additionally excites the excited pulses during reception the electrical voltage is discrete in time on the transducer, the measured transmitting functions of the receive and the radiation are fixed according to the measured values tim, which is determined by the characteristics of the transducer. (f ( ten