A Nonlinear Lamb Wave Mixing Method for Stress Distribution Measurement in Sheet Metal

Abstract

A nonlinear Lamb wave mixing method for the measurement of stress distribution in sheet metal. The invention discloses a stress distribution detection method based on nonlinear Lamb wave mixing technology, which is suitable for stress distribution detection and location of stress concentration areas in plate structures, and belongs to the field of non-destructive detection. Steps of the present invention: the method first determines the excitation frequencies of the two fundamental frequency waves according to the measured object and the nonlinear Lamb wave mixing resonance condition; two columns of A0 modal waves are oppositely excited at the left and right ends of the test piece, and between the excitation signals The sum frequency S0 signal is received at a certain position in the interval, and the nonlinear mixing frequency stress detection of the plate structure is carried out; by changing the excitation delay of the excitation signal, the mixing frequency scanning is performed on different positions of the specimen, and the amplitude of the mixing wave is extracted; finally, according to The change law of the sum frequency difference signal amplitude with the mixing position can realize the detection of the stress distribution of the metal plate and the location of the stress concentration area.

Description

technical field [0001] The invention relates to a non-linear Lamb wave mixing detection method for stress distribution of a plate structure, which is suitable for stress distribution detection and location of a stress concentration area in a plate structure, and belongs to the field of non-destructive testing. Background technique [0002] As a common structural form, metal plate structures are widely used in various major infrastructures due to their good formability and weldability, such as ship shells, aircraft fuselages and hatches, and large oil storage tank shells. Wait. Under the joint action of static force and cyclic load, internal medium and external working environment during use, metal components are prone to stress concentration at sudden changes and rigidly constrained parts, and evolve into fatigue cracks or fractures, resulting in failure of structural components. resulting in catastrophic accidents. Therefore, in order to eliminate potential safety hazards...

AI Technical Summary

Problems solved by technology

However, the research on stress detection using nonlinear ultrasonic mixing technology in domestic and foreign literature is still in the exploratory stage.

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