Method for extracting time-frequency amplitude characteristic and time-frequency phase characteristic of ultrasonic signals on dissimilar material diffusion welding interface

Abstract

The invention relates to a method for extracting the time-frequency amplitude characteristic and the time-frequency phase characteristic of ultrasonic signals on a dissimilar material diffusion welding interface, belonging to the filed of the nondestructive detection and aiming at solving the problem that the conventional method for detecting the diffusion welding quality according to the amplitude of the reflection echo on the diffusion welding interface can not accurately reflect the information on the diffusion welding defect. The method comprises the following steps: collecting ultrasonic signals from the dissimilar material diffusion welding interface; collecting reference signals from a reference sample; continuously changing the wavelets of the ultrasonic signals collected from the dissimilar material diffusion welding interface and the reference signals collected from the reference sample by using the parameter-optimized complex Morlet wavelets to obtain the ratio (R) (a, b) of the ultrasonic signals and the reference signals; respectively calculating the time-frequency amplitude |R (a, b)| and the time-frequency phase Phi (a, b) of the ultrasonic signals collected from the dissimilar material diffusion welding interface by using the R (a, b); respectively calculating the time-frequency amplitude characteristic value CR and the time-frequency phase characteristic value CPhi by using the time-frequency amplitude |R (a, b)| and the time-frequency phase Phi (a, b); and reconstructing the time-frequency amplitude characteristic value CR image and the time-frequency phase characteristic value CPhi image of the ultrasonic signals collected from the dissimilar material diffusion welding interface. The invention is suitable for detecting and evaluating the quality of the diffusion welding interface.

Description

Technical field [0001] The invention relates to the field of non-destructive testing, in particular to a method for extracting time-frequency amplitude characteristics and time-frequency phase characteristics of ultrasonic signals at the interface of dissimilar material diffusion welding. Background technique [0002] At present, diffusion welding is more and more widely used in advanced technology fields such as aviation, aerospace and nuclear industry. How to detect and evaluate the quality of diffusion welding interface has become an important topic in the field of non-destructive testing. Diffusion welding defects mainly include unsoldering, weak joints and micro gaps. Since the defects are located at the interface, conventional ultrasonic flaw detection methods are often used for detection. This method uses the reflected echo generated by the ultrasonic wave at the defect, and judges the size and orientation of the defect by the magnitude of the echo amplitude, which is very...

AI Technical Summary

Problems solved by technology

[0003] In order to solve the problem that the amplitude of the reflected echo of the conventional diffusion welding interface cannot accurately reflect the defect information of the diffusion welding, the present invention provides a time-frequency amplitude feature and time-frequency phase feature extraction method of the ultrasonic signal of the diffusion welding interface of different materials

Images