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Nondestructive high-sensitivity magnetic detection of corrosion in light pole bases
Published in Hiroshi Yokota, Dan M. Frangopol, Bridge Maintenance, Safety, Management, Life-Cycle Sustainability and Innovations, 2021
T. Ishikawa, K. Tsukada, H. Furuta
The Eddy-current Testing or Electromagnetic Testing (E.T) is often used as a nondestructive testing for detection of surface flaws. However, the E.T cannot be applied to detection of inner corrosion of steel structures. A nondestructive high-sensitivity magnetic measurement technology under a SIP project of “nondestructive high-sensitivity magnetic inspection for assessment of infrastructure deterioration and maintenance planning” (Keiji Tsukada, research and development officer, Okayama University) was a new technology for nondestructive measurement of the amount of corrosion in a steel plate. Extremely Low-Frequency Eddy Current Testing with Spectrum Analysis of Magnetic field (ELECT-SAM) was developed for detection of inner corrosion of steel structures (Tsukada et al. 2016, 2017 and 2018). Figure 2 shows the system of ELECT-SAM. This nondestructive testing system can detect inner corrosion by extremely low frequency with employing a magnetic probe using an anisotropic magnetic resistance (AMR) sensor. To inspect the inner defects of the steel plate, a low frequency of eddy current testing is required (Tsukada et al. 2016 and Akutsu et al. 2018). In this system, to estimate the remaining plate thickness, the calibrated equations obtained by magnetic spectrum analysis are prepared. The probe of conventional ELECT-SAM was assumed to the perpendicular to the surface of the steel plate, as shown in Figure 3(a).
Inspection of Bingo Bridge by using high-sensitivity magnetic nondestructive testing
Published in Nigel Powers, Dan M. Frangopol, Riadh Al-Mahaidi, Colin Caprani, Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges, 2018
T. Ishikawa, Y. Kuramitsu, H. Furuta, K. Tsukada
As generally know, the Eddy-current Testing or Electromagnetic Testing (E.T) is widely used as a nondestructive testing for detection of surface flaws. However, the E.T cannot be applied to detection of inner fatigue crack or inner corrosion of steel structures. Extremely Low-Frequency Eddy Current Testing with Spectrum Analysis of Magnetic field (ELECT-SAM) was developed for detection of inner corrosion of steel structures (Tsukada et al. 2016). Figure 5 shows the system of ELECT-SAM. This nondestructive testing system can detect inner corrosion at extremely low frequency by employing a magnetic probe using an anisotropic magnetic resistance (AMR) sensor with the sensitivity of 1 nT/Hz. In this system, to estimate the plate thickness, the calibrated equations obtained by magnetic spectrum analysis of each material are prepared.
Computational Nondestructive Evaluation (CNDE)
Published in Sourav Banerjee, Cara A.C. Leckey, Computational Nondestructive Evaluation Handbook, 2020
Sourav Banerjee, Cara A.C. Leckey
Electromagnetic testing [13] induces electric currents, and/or magnetic fields inside a material and measures the electromagnetic response in order to detect cracks, fractures, faults, corrosion, and other defects in the materials. Electromagnetic methods include Eddy current testing [14], remote field testing (RFT) [14], magnetic flux leakage (MFL) [14], and alternating current field measurement (ACFM) [15], among others.
Ground penetrating radar applications and implementations in civil construction
Published in Journal of Structural Integrity and Maintenance, 2023
Macy Spears, Saman Hedjazi, Hossein Taheri
The use of electricity or magnetism to identify flaws and defects in materials describes electromagnetic testing (ET), which consists of a variety of indirect testing methods. The electromagnetic (EM) responses of the tested material are measured by an electric current or magnetic field effect. A popular non-invasive technique that is based on the principles of electromagnetic energy pulses is ground penetrating radar (GPR), which is used for the detection and imaging of buried or hidden objects (Lai et al., 2018). This radar technology has been employed in a variety of practices like archaeological and forensic investigations, but GPR is proving to be a powerful EM approach for the monitoring and maintenance of infrastructure due to the portability and effectiveness it has to offer. Specifically related to construction applications, GPR has the potential to assess the conditions of pavement, buildings, bridges, railways, soil and buried pipes. An analysis of these structures and systems with implementation of GPR is discussed further in this paper, as well as the data acquisition and processing commonly used for obtaining accurate results.
Quantitative nondestructive testing of wire rope based on pseudo-color image enhancement technology
Published in Nondestructive Testing and Evaluation, 2019
Wire rope comprised of carbon steel wires, has the advantages of high tensile strength, good bending performance, high elasticity and highly variable strand-packing structures. It is widely used in mining, transportation, construction and other industries. The usefulness for any application, as well as the safety of personnel [1], relies significantly on its mechanical characteristics. Thus, it is very important to detect the damage of wire rope while it is in service. At present, there are several representative methods for detecting damage in wire rope, including ultrasonic, infrared, and optical radiation, x-rays, acoustic emission and electromagnetic detection. Among these, electromagnetic testing (EMT) has the advantages of low cost, high reliability, and suitability for online inspection. Among currently available EMT instruments are those which utilize measurements of eddy currents, magnetic particles, magnetic flux leakage (MFL), magnetic memory, microwave reflectivity, and other structural probes. Among these, the MFL method can detect the surface and internal defects of wire rope and has been popular for its low-cost engineering design and portability. The MFL detection method relies on the effect of a surface or internal defect on a distortion in the magnetic field of the wire, causing a leakage magnetic field (LMF) on its surface. The wire defects are found by magnetizing the wire rope in the presence of an applied saturating, steady-state magnetic field. The defects appear locally as changes or discontinuity in the spatial pattern of field lines (LMF) that radiate from the wire’s surface. When a wire rope with no defects is magnetized to saturation, the magnetic line of flux runs mainly parallel to the rope surface because of the constraining material’s high permeability. Thus, there is very small flux leakage (MFL) radially outward on the rope’s surface. However, if there is a defect along the wire rope, some of the magnetic flux leaks radially outward from the rope surface because of sharply reduced permeability. The MFL strength outward from the wire surface is measured at multiple points circumferentially along the wire surface to localize the defect using a magnetic sensor.