Tap-scanning method for detecting structural damages

Abstract

The invention belongs to the technical field of structural nondestructive detection and in particular relates to a tap-scanning method for detecting structural damages. The method comprises the following steps: scanning along the surface of a structure to be detected by using a tapping device provided with an acceleration transducer and describing the relations between the acceleration a of the tapping device and structural displacement response b, a structural local impedance Z and a tapping force F by using an approximate formula (shown above); segmenting an acceleration signal and subjecting the acceleration signal to transform processing to obtain a spectrogram of the acceleration signal; intercepting a spectrum envelope corresponding to a frequency band covered by a preset tapping force and recording the spectrum envelope by using vectors; and obtaining an MAC coefficient matrix. A curved line is drawn by using the values of a row of elements selected from the MAC coefficient array as the elements of a vertical axis and using corresponding structural positions to form a horizontal axis, and if a structure has no damage, the curved line is smooth; and if the curved line declines suddenly at a certain position, a damage occurs at the position, and a greater the declination represents a more serious damage.

Description

technical field [0001] The invention belongs to the technology in the field of structural non-destructive testing, in particular to a percussion scanning method for structural damage testing. Background technique [0002] During the manufacture and use of engineering structures, some local damages, such as cracks, pits, debonding, etc., will often occur due to technological reasons or the use of loads. The accumulation of these damages to a certain extent will affect the normal use of the structure. In order to ensure the normal operation of the structure, it needs to be inspected for damage before it is put into use or after a period of service. For example, a bridge needs to be tested before it is opened to traffic to ensure that it meets the design requirements. During the service period, regular routine inspections or irregular special inspections are required to detect damage in the structure in time; Components can be delivered for use only if their internal damage is...

AI Technical Summary

Problems solved by technology

However, this method does not install a knocking device on the vehicle, so it is difficult to excite the high-frequency response of the bridge, and it is difficult to detect structural damage based on the fundamental frequency of the bridge

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