Material non-destructive inspection method and device based on nonlinear acoustics

A nonlinear acoustic and non-destructive testing technology, which is applied in the processing of detection response signals, and the use of sound waves/ultrasonic waves/infrasonic waves to analyze solids, etc., can solve problems such as restricting development and application, reducing axial resolution, and reducing the ability to detect small defects. , to improve detection capability, reduce non-linearity, benefit cost and complexity

Inactive Publication Date: 2012-09-26
PEKING UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, a longer emission pulse also means a reduction in axial resolution, which means a reduction in the ability to detect small defects
Therefore, the nonlinear acoustic detection system using the traditional Tone Burst transmission signal has the insurmountable problem of mutual restriction between the nonlinear detection ability and the axial resolution ability, which greatly restricts its development and application.

Method used

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  • Material non-destructive inspection method and device based on nonlinear acoustics
  • Material non-destructive inspection method and device based on nonlinear acoustics
  • Material non-destructive inspection method and device based on nonlinear acoustics

Examples

Experimental program
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Embodiment 1

[0095] Such as Figure 7 As shown, a material non-destructive testing device based on nonlinear acoustics (see Figure 7 ), including: a scanning platform for mechanically scanning the specimen, a signal generating unit 1, a transmitting digital / analog converter 2, a transmitting power amplifier and a matching network 3, a synchronization unit 4, a receiving signal processing unit 5, and a transmitting transducer Device 7, receiving transducer 8, receiving preamplifier 9, receiving analog / digital conversion unit 10,

[0096] The signal generation unit 1 is used to generate a Gaussian envelope transmission signal, the unit generates the data of all sampling points of the transmission signal, and then sends the generated data into the transmission D / A converter 2 to convert it into an analog signal; the signal generation unit 1 It is connected with the transmission power amplifier and matching network 3, and the generated signal is sent to the transmission power amplifier for a...

Embodiment 2

[0106] Such as Figure 8 As shown, the transmitting and receiving transducers are mounted on a three-dimensional precision mechanical scanning device. By positioning the transducer at a specific position of the test piece by the scanning device, and then performing the above-mentioned transmitting-receiving-processing steps, the nonlinear acoustic characteristics of the test piece located at the focal point of the transmitting transducer can be obtained. Through the movement of the scanning device, changing the relative position of the transmitting transducer and the test piece, and repeating the above steps at each position, the scanning of the whole test piece can be realized. In particular, by using a transmitting transducer with a small relative aperture (F number) to obtain a small axial focal length, combined with the higher axial resolution of this method, it is possible to achieve Scanning in the direction of the sound beam can complete the three-dimensional nonlinear...

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Abstract

The invention discloses a material non-destructive inspection method and a material non-destructive inspection device based on nonlinear acoustics. The material non-destructive inspection method comprises the following steps that a Gaussian envelope is used for carrying out windowing on base frequency signals to form emitting signals; all subharmonic components in receiving signals are respectively subjected to filtering by a corresponding band-pass filter at the receiving end for realizing the separation of components at different frequencies; and in addition, all separated subharmonic components are subjected to corresponding matched filtering treatment for realizing the optimal detection of all harmonic components. The nonlinear acoustic detection method provided by the invention has the advantages that the frequency domain aliasing among all subharmonic components in signals is small, the nonlinear detection capability is high, and meanwhile, higher axial resolution capability is realized.

Description

technical field [0001] The invention relates to the field of non-destructive testing methods and equipment for solid materials, in particular to a method and device for detecting internal structures and defects of materials by using nonlinear acoustic characteristics generated by sound waves propagating in materials and structures. Background technique [0002] At present, ultrasonic (or acoustic) nondestructive testing technology has been widely used in the field of material nondestructive testing. The current acoustic nondestructive testing technology is mainly based on linear ultrasound, and the main applied technologies are: ultrasonic C-scan testing, phased array ultrasonic testing, ultrasonic guided wave testing, laser ultrasonic testing, etc. [1] [2]. These ultrasonic testing methods all use linear ultrasound, that is, the amplitude of the detection ultrasonic wave used in the detection is extremely small, and the stress and strain generated by the ultrasonic wave pro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N29/04G01N29/44
Inventor 高鹏李法新
Owner PEKING UNIV
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