A novel method for steel bar all-stage pitting corrosion monitoring using the feature-level fusion of ultrasonic direct waves and coda waves

Abstract

Corrosion monitoring of steel bars has drawn extensive attention in recent decades. Conventional ultrasonic method, utilizing direct waves to detect damage, is adequate for severe pitting corrosion but suffers from low sensitivity to incipient pitting corrosion. Coda wave technique, a very sensitive method to subtle changes in medium using later arrival wave packets, is innovatively introduced to monitor pitting corrosion of steel bars, especially in the early stages. The decorrelation coefficient (DC) values are calculated to quantify the variations of both direct waves and coda waves. To overcome the limitations of coda waves for severe pitting corrosion and remedy the low sensitivity of direct waves for incipient pitting corrosion, a feature-level data fusion strategy is proposed to integrate the two probing waves to monitor all-stage pitting corrosion of steel bars. The combination of direct waves and coda waves could exploit the complementary merits in various pitting corrosion configurations. The proposed feature-level fusion strategy of ultrasonic coda waves and direct waves intercepted from the same recorded signals opens a new perspective in all-stage pitting corrosion monitoring of steel bars and contributes a novel scheme for whole-process damage evaluation of structures.

Grading Evaluation of Overall Corrosion Degree of Corroded RC Beams via SMFL Technique

“…Ten, the magnetic feld dH of the double rectangulargroove magnetic dipole model at any point P (y and z) in space is the sum of the magnetic feld vectors generated by the magnetic charge microelements, and its magnetic feld components in Y and Z directions can be expressed by equations (10) and (11) as follows:…”

“…Terefore, rebar corrosion detection has received considerable attention due to the increasing awareness about the durability and safety of reinforced concrete structures, particularly rebar. To this day, scholars at home and abroad have conducted a lot of research work in the feld of nondestructive testing (NDT) of concrete reinforcement corrosion by mainly including ultrasonic waves technique [10,11], acoustic emission (AE) [12,13], fber optical corrosion sensors (FOCS) [14], electrochemical impedance spectroscopy [15], eddy current testing (ECT) [16], radiography [17], half-cell potential measurements (HCP) [18], infrared thermograph (IT), and self-magnetic fux leakage (SMFL).…”

Bolt tightness monitoring using multiple reconstructed narrowband Lamb waves combined with piezoelectric ultrasonic transducer

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A time-reversal assisted probabilistic fusion strategy for damage localization in plate-like structures using Lamb waves

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