Damage positioning imaging method and system based on non-linear Lamb wave zero frequency component

Abstract

The invention belongs to the field of plate wave early-stage damage nondestructive testing, and particularly relates to a damage positioning imaging method and system based on a nonlinear Lamb wave zero-frequency component, and the method specifically comprises the steps: 1, preparing a model to be detected; 2, transmitting a fundamental wave at a signal excitation point of the model, receiving a zero-frequency signal at the damaged position of the model by a signal receiving point, and obtaining a boundary point at the damaged position of the model; 3, signal excitation and signal receiving are carried out at multiple positions on the model, and a boundary dot matrix is obtained; and 4, performing model damage position positioning imaging according to the boundary dot matrix. The boundary of the material damage is determined by utilizing the high reflection characteristic of zero frequency to the early local damage of the material, so that the position of the material damage is positioned and imaged, the positioning method is simple and efficient, the detection of the early local damage can be as simple as the detection of the macroscopic damage (such as local 1cm cracks) of the material by utilizing linear fundamental waves, and the detection accuracy is high. And related bottlenecks of mixed wave and second harmonic technologies are overcome.

Description

technical field [0001] The invention belongs to the field of plate wave early damage detection, and in particular relates to a damage location imaging method and system based on a nonlinear Lamb wave zero-frequency component. Background technique [0002] The plate and shell structure has excellent performance and is widely used in all walks of life. These plate and shell structural materials will be more or less affected by stress, high temperature, high pressure and corrosion during use, and are very prone to damage such as fatigue, plasticity, corrosion and creep, which will gradually degrade the performance of the plate and cause an explosion. Safety accidents such as breakage, breakage and leakage of hazardous substances threaten the operation of equipment and the safety of personnel's lives and property, causing major social and economic losses. Therefore, it is a very important research topic in our country's national economic production and life to study powerful no...

AI Technical Summary

Problems solved by technology

The above scheme adopts two sets of detection models without early fatigue damage and those with early fatigue damage. Through the matrix integral of the detection part of the two sets of detection models, the probability distribution map of the detection part with early fatigue damage is obtained. The above scheme uses two sets of models For group comparison, there is no definition standard for the model without early damage, and it is impossible to judge whether the model without early damage is really damage-free, and the test results obtained by comparison are inaccurate, and even the early fatigue damage detection of the test material cannot be realized

[0009] Document 1: "SUN X Q, LIU H J, ZHAO Y X, et al. The zero-frequency component of bulk waves in solids with randomly distributed micro-cracks [J]. Ultrasonics, 2020, 107: 106172.", the applicant here It is pointed out that microcracks can reflect zero frequency, so that the purpose of locating microcrack damage at zero frequency can be achieved, but the damage is limited to microcrack damage, and the research is limited to body wave

In the field of plate wave early damage detection, due to the weak second harmonic reflection, the inertial thinking is not to use the second harmonic reflection for damage location, but to use the difference frequency and sum frequency generated by frequency mixing to locate, but the frequency mixing detection technology There is a technical bottleneck. This method needs to calculate and control the time difference of the mixed wave, requires scanning, and the operation is complicated. In principle, there are limitations of resonance conditions, which is inconvenient to use.

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