Ultrasonic micro-damage location detection method and device based on collinear aliasing of Lamb waves

Abstract

The invention relates to nondestructive testing, and provides an ultrasonic micro-damage location detection method based on collinear aliasing of Lamb waves. The method comprises the following steps: (A), a pair of Lamb wave mode combinations with different frequency and propagation modes is determined; (B), generated difference frequency harmonic waves of the Lamb waves are determined; (C), the pair of initial Lamb wave modes are excited by signal excitation units; (D), a signal receiving unit having corresponding frequency with the difference frequency harmonic waves is selected to receive the difference frequency harmonic waves; (E), an area where beams start for aliasing is confirmed; (F), positions of two initial excitation sources are changed; (G), scanning detection is performed on a tested object; and (H), the micro-damage location of the tested object is calculated and confirmed according to amplitude change of the difference frequency harmonic waves. The invention further provides an ultrasonic micro-damage location detection device based on the collinear aliasing of the Lamb waves. The device comprises a first computer, a signal generator, a first signal excitation unit, a second signal excitation unit, a signal receiving unit, an oscilloscope and a second computer. The ultrasonic micro-damage location detection method and device are applied to material detection.

Description

Technical field [0001] The present invention relates to non-destructive testing, in particular to ultrasonic testing. Specifically, it is a method for non-destructive evaluation and characterization of micro-damages or micro-defects such as early fatigue damage of materials and early degradation of material properties. It is based on the nonlinearity of Lamb wave collinear aliasing Realized by ultrasound technology. Background technique [0002] For the key load-bearing structural parts of important equipment such as aerospace and nuclear power that have been in service for a long time, the performance degradation of structural materials is inevitable, such as tensile performance degradation, thermal fatigue creep damage, and reduced bond strength. In order to ensure the safe operation of these key structural parts, it is very important to develop technical means for early performance degradation assessment of structural materials. Lamb waves propagating in structural materials ...

AI Technical Summary

Problems solved by technology

[0006] 2. Unable to determine the location of the damage causing the nonlinear response

[0007] The nonlinear value measured by the nonlinear Lamb wave technology based on the second-order harmonic method includes the nonlinear value of the entire area from the signal excitation transducer to the signal receiving transducer, so this technology cannot accurately determine the detection area Specific location of damage causing nonlinear response

The nonlinear Lamb wave detection technology based on the second-order harmonic method can only qualitatively estimate the nonlinear change of the material, but cannot accurately determine the damage location. This limitation will affect the accuracy of the nonlinear Lamb wave detection technology

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