GB2262604A

GB2262604A - Acousto-ultrasonic testing instrument with coupling condition measurement

Info

Publication number: GB2262604A
Application number: GB9126679A
Authority: GB
Inventors: Shifeng Liu
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-12-16
Filing date: 1991-12-16
Publication date: 1993-06-23
Also published as: GB9126679D0

Abstract

An Acousto-Ultrascnic (AU) testing instrument has coupling condition measurement device. The uncertain of coupling condition becomes certain known for this AU testing instrument. The effect of coupling condition on the results of AU testing measurement can be eliminated and/or calibrated. The final measurement of AU testing can be acoustic wave data in the material tested close to the transmitting transducer 8 and close to the receiving transducer 9. <IMAGE>

Description

ACOUSTO-ULTRASONIC TESTING INSTRUMENT WITH COUPLING CONDITION NIEASURENIENT This invention relates to Acousto-Ultrasonic (AU) technique and acoustic coupling condition measurement.

AU testing technique, also known as the Stress-Wave-Factor (SWF) technique, can be used to measure various properties (mechanical properties, anomalies and defects) of many types of solid materials. The principle of AU testing is to measure the interaction (attenuation, scattering, wave mode conversion, etc.) between the material tested and modulated ultrasonic wave signals inputted from AU testing instrument. The AU testing instrument generates modulated ultrasonic wave signals, inputs the signals into the materials tested, measures and analyzes the signals after their propagation through the material tested (i.e. after the interaction). Generally, two piezoelectric transducers are used as ultrasonic wave transmitter and receiver respectively.Because of the uncertain of the coupling conditions between both transmitting transducer and receiving transducer and the material tested, a poor reproducibility of AU testing measurement may be obtained. This poor reproducibility limits the application of AU testing technique in industries and science research.

This invention provides an AU testing instrument with coupling condition measurement. Figure 1 is tile function block diagram of the AU testing instrument according to the present invention. In Figure 1, numberl is transmitting transducer, number 2 is receiving transducer, number3 is pulse generator, number4 is a microprocessor controller, number 5 is data acquisition device, number 6 and number 7 are pre-amplifiers. The lines between the blocks in Figure 1 indicate the function connections of the blocks. So that, both number 1 transmitting transducer and number 2 receiving transducer can obtain modulated electric pulse from number 3 pulse generator for modulated ultrasonic wave generation, and also can export receiving signals through number6 and number 7 pre-amplifiers to number 5 data acquisition device.Number 4 microprocessor controller is used to control number 3 pulse generator and number 5 data acquisition device, to synchronize pulse generation and measurement, and to analyze data.

Figure 2 shows a general transducer for both number 1 transmitting transducer and number 2 receiving transducer, and its working principle. In Figure 2, number 8 is a piezoelectric transducer for transmitting and number 9 is another piezoelectric transducer for receiving. Both transmitting transducer number 1 or receiving transducer number 2 in Figure 1 consists of number 8 and number 9 two piezoelectric transducers. So that there are two piezoelectric plates in a single transducer case for a single transmitting transducer number or receiving transducer number 2. Number 10 is couplant, number 11 is the material tested, and number 12 is the medium material outside the material tested. The arrows in Figure 2 indicate the wave propagation path.In order to obtain number 14, the transmitting signal in tlle material tested, and number 15, the receiving signal in the material tested, a calculation programme is included in the number 4 microprocessor controller. Based on acoustic propagation theory, numberl4 transmitting signal and number 15 receiving signal, in the material tested and close to the transducers respectively, can be obtained by calculation when number 13 instrument inputting signal, number 16 instrument receiving signal, the acoustic properties of number 12 medium material and the function of wave propagation in the material tested are known. Coupling condition can also be measured by the calculation of number 13 instrument inputting signal deducting number 14 transmitting signal or number 15 receiving signal deducting number 16 instrument receiving signal.

The signals described above can be any parameters of the measurements of acoustic wave, acoustic emission and stress wave factor such as ring-down count, amplitude, energy etc..

Claims

1. An Acousto-Ultrosonic testing instrument using coupling measurement device or function illustrated in Figure 1.

2. An Acousto-Ultrasonic testing instrument as claimed as Claim 1 wherein a two piezoelectric plate transducer is provided as illustrated in Figure 2. The two piezoelectric plates are included in a single transducer case. The transducer may be various specifications(frequency, size, wave mode, etc.) required by different test purposes.

3. A Acousto-Ultrasonic testing instrument claimed in Claiml and a two piezoelectric plate transducer as claimed in Claim 2 wherein a measurement method for coupling condition is provided in the illustration of Figure 2.

Amendments to the claims have been filed as follows 1. An Acousto-Ultrasonic testing instrument comprising two transducers, two preamplifiers connecting with the two transducers, a pulse generator connecting with both transducers, a data acquisition device, a microprocessor controller including a calculation programme; 2. An Acousto-Ultrasonic testing instrument as claimed 1 wherein two all transducers connected with pre-amplifiers and pulse generator both, are provided; 3. An Acousto-Ultrasonic testing instrument as claimed 1 or 2, wherein a transducer with two piezoelectric plates connected with a pre-amplifier and pulse generator respectively, is provided.