Crack detection method and system based on piezoelectric sensor and elastic wave propagation mechanism

Abstract

The invention discloses a crack detection method and system based on a piezoelectric sensor and an elastic wave propagation mechanism, and the method comprises the steps: 1) taking a metal structure containing the piezoelectric sensor and a microcrack as a research object, building a kinetic model of the piezoelectric sensor based on elastodynamics, analyzing electromechanical coupling characteristics and load transmission between the piezoelectric sensor and the matrix structure; 2) based on the established sensor model and fracture mechanics, establishing a multi-scattering forward model of elastomer waves between multiple sensors and multiple cracks, and solving a relationship between sensor output signals and crack parameters; and 3) substituting the forward model into the optimization process, and estimating the crack characteristics through partially measured sensor voltage signals. The method has the advantages that the precision of a near-field microcrack estimation result is improved, and irregular cracks can be estimated.

Description

technical field [0001] The invention mainly relates to the technical field of metal material micro-crack detection, in particular to a crack detection method and system based on a piezoelectric sensor and an elastic wave propagation mechanism. Background technique [0002] Damage detection based on recording and diagnosing elastic body waves by piezoelectric sensors has the advantages of good high-frequency characteristics, and has become a key technology and research hotspot in early microcrack detection. However, most of the existing research ignores the influence of the piezoelectric sensor itself, resulting in inaccurate detection results, especially for small local damages near the sensor. There is less research. The existing research still has the following difficult problems to be solved urgently in the dynamic modeling of piezoelectric sensors, high-frequency elastic body wave forward modeling, and crack detection and inversion estimation technology, including: [...

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Problems solved by technology

[0003] (1) Modeling of piezoelectric sensors: static model research is relatively mature, but dynamic model research is not sufficient

In the process of solving the dynamic response of piezoelectric sensors under high-frequency excitation, the existing numerical methods will introduce very complex stiffness matrices and super-large calculations, and cannot give the direct physical meaning of the numerical results

However, the existing simplified theoretical model cannot accurately estimate the local deformation at the stress concentration at both ends of the piezoelectric sensor, especially the mutual influence between adjacently arranged multi-sensors needs to be further studied

[0004] (2) Forward modeling of elastic body waves: There have been many solutions to the problem of multiple scattering of elastic waves between cracks, but most of them ignore the influence of piezoelectric sensors on elastic wave scattering, and the research on irregular cracks is relatively limited. few

Existing studies have explored the use of strain signals around cracks to identify cracks, but the impact on the coupling of sensors and monitoring structures has not been fully considered, and the applicability of crack estimation methods under working conditions needs further study

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