Colinear frequency mixing ultrasonic detection method for mechanical property degradation of tank torsion shaft

Abstract

The invention discloses a colinear frequency mixing ultrasonic detection method for mechanical property degradation of a tank torsion shaft. A coupling agent is utilized to respectively bond a longitudinal wave ultrasonic transducer and a transverse wave ultrasonic transducer on the two sides of a tank torsion shaft torsion fatigue test piece to excite an excitation longitudinal wave and an excitation transverse wave and receive a signal wave. The occurrence time of a frequency mixing wave is worked out through theoretical calculation, the frequency mixing wave signal is added with a calibrated time window for achieving signal judgment, and the interference of a reflected signal caused by curved surfaces at different shaft diameters when the tank torsion shaft test piece is in transition between a parallel section and a non-parallel section is eliminated. The frequency mixing wave signal after windowing is processed by adopting a full-phase inversion method, the all-phase signal of thefrequency mixing wave is subjected to phase reversal processing, and the frequency mixing wave signal is further extracted. Finally, the experimental result subjected to phase reversal processing isprocessed through a spectral analysis method, and a nonlinear energy parameter of energy distribution in a frequency mixing frequency range is extracted from a frequency domain graph of the spectral analysis method.

Description

technical field [0001] The invention belongs to the field of non-destructive detection of metal materials, and in particular relates to a detection system for detecting the degradation of mechanical properties of a tank torsion shaft based on collinear frequency mixing nonlinear ultrasonic waves. Background technique [0002] When the mechanical properties of the materials that make up the structure change, the structural properties will inevitably change. Material performance change is a time-varying process, which can generally be divided into three stages: early performance degradation (including physical and chemical aging and degradation), initiation and accumulation of damage (hole formation and cracking), and fracture failure. For most materials, early performance degradation stages occupy most of their lifetime. The research shows that metal materials under cyclic loading, from the generation of a large number of dislocation groups inside the material to the formati...

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Problems solved by technology

However, at present, the prediction work for the fatigue life of military equipment has not yet been carried out

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