879 research outputs found
Evaluation of eddy current and magnetic techniques for inspecting rebars in bridge barrier rails
This paper reports on a feasibility study of using eddy current (EC) and magnetic flux leakage (MFL) methods to detect corrosion damage in rebars that anchor concrete barrier rails to the road deck of bridge structures. EC and MFL measurements were carried out on standalone rebars with and without artificial defects of 25% and 50% material loss, using a commercial EC-based rebar locator and a MFL system that was developed using giant magnetoresistance sensors to detect leakage fluxes from the defects. Both techniques can readily detect the defects at a distance of 2.5β³ (63.5 mm). The amplitudes of the EC and MFL signals vary monotonically with the amount of material loss, indicating the potential of using the techniques to quantify material loss of standalone rebars
Feasibility Study for Detection and Quantification of Corrosion in Bridge Barrier Rails
Technical challenges exist with infrastructure that can be addressed by nondestructive evaluation (NDE) methods, such as detecting corrosion damage to reinforcing steel that anchor concrete bridge railings to bridge road decks. Moisture and chloride ions reach the anchors along the cold joint between the rails and deck, causing corrosion that weakens the anchors and ultimately the barriers.
The Center for Nondestructive Evaluation at Iowa State University has experience in development of measurement techniques and new sensors using a variety of interrogating energies. This research evaluated feasibility of three technologiesβx-ray radiation, ground-penetrating radar (GPR), and magnetic flux leakage (MFL)βfor detection and quantification of corrosion of embedded reinforcing steel.
Controlled samples containing pristine reinforcing steel with and without epoxy and reinforcing steel with 25 percent and 50 percent section reduction were embedded in concrete at 2.5 in. deep for laboratory evaluation. Two of the techniques, GPR and MFL, were used in a limited field test on the Iowa Highway 210 Bridge over Interstate 35 in Story County.
The methods provide useful and complementary information. GPR provides a rapid approach to identify reinforcing steel that has anomalous responses. MFL provides similar detection responses but could be optimized to provide more quantitative correlation to actual condition. Full implementation could use either GPR or MFL methods to identify areas of concern, followed by radiography to give a visual image of the actual condition, providing the final guidance for maintenance actions
ΠΠ°ΠΊΠ»Π°Π΄Π½ΡΠ΅ Π²ΠΈΡ ΡΠ΅ΡΠΎΠΊΠΎΠ²ΡΠ΅ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»ΠΈ: ΡΠΈΡΡΠ΅ΠΌΡ Π²ΠΎΠ·Π±ΡΠΆΠ΄Π΅Π½ΠΈΡ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΠ»Π΅ΠΊΡΡΠΎΠΌΠ°Π³Π½ΠΈΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠ»Ρ (ΠΎΠ±Π·ΠΎΡ)
Development of technical tools with improved metrological and operational characteristics is the actual problem of the eddy current testing. Ensuring the optimal distribution of the electromagnetic excitation field in the testing zone carries out confident detection of the defects and determination of their geometrical parameters by means of eddy current testing. The purpose of the work was to conduct an analysis of scientific and technical information in the field of eddy current testing to study of the use of electromagnetic excitation fields with a priori specified properties, as well as to generalize and systematize the accumulated experience and approaches to conduct theoretical research in this direction.A review of publications in the field of non-destructive electromagnetic testing devoted to the improvement of the excitation systems of eddy current flaw probes was carried out. The authors considered approaches in which a uniform distribution of the electromagnetic field on the control object surface was achieved by linear and non-linear optimal synthesis of excitation systems, provided the immobility of the probe relative to the testing object. Analysis of eddy current probe designs with a homogeneous excitation field created by circular, rectangular tangential and normal coils, as well as by creating a rotational excitation field was carried out. The authors studied designs of the excitation coils of probes with fields of complex configuration characterized by the original fractal geometry which can increase the probability of identifying defects that were not amenable to detection by classical probes.Studies that suggested the formation of optimal configuration fields in a given area using magnetic cores, field concentrators made of conductive materials and specially shaped screens were analyzed. The authors studied approaches to the implementation of the optimal synthesis of excitation systems of probes with uniform sensitivity in the testing zone using surrogate optimization for cases of moving testing objects taking into account the speed effect.The experience, as well as the results of theoretical studies devoted to the problem of designing eddy current probes with uniform sensitivity in the testing zone due to the uniform density distribution of the induced currents flowing in the object were generalized and systematized. As a result, the classification of probes on a number of features that characterize the excitation systems was proposed.ΠΠΊΡΡΠ°Π»ΡΠ½ΠΎΠΉ Π·Π°Π΄Π°ΡΠ΅ΠΉ Π²ΠΈΡ
ΡΠ΅ΡΠΎΠΊΠΎΠ²ΠΎΠ³ΠΎ ΠΊΠΎΠ½ΡΡΠΎΠ»Ρ ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠ° ΡΠ΅Ρ
Π½ΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΡΠ΅Π΄ΡΡΠ² Ρ ΡΠ»ΡΡΡΠ΅Π½Π½ΡΠΌΠΈ ΠΌΠ΅ΡΡΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ ΠΈ ΡΠΊΡΠΏΠ»ΡΠ°ΡΠ°ΡΠΈΠΎΠ½Π½ΡΠΌΠΈ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌΠΈ. Π£Π²Π΅ΡΠ΅Π½Π½ΠΎΠ΅ ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΠ΅ Π΄Π΅ΡΠ΅ΠΊΡΠΎΠ² ΠΈ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ ΠΈΡ
Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΡΡΠ΅Π΄ΡΡΠ²Π°ΠΌΠΈ Π²ΠΈΡ
ΡΠ΅ΡΠΎΠΊΠΎΠ²ΠΎΠ³ΠΎ ΠΊΠΎΠ½ΡΡΠΎΠ»Ρ ΠΎΡΡΡΠ΅ΡΡΠ²Π»ΡΠ΅ΡΡΡ ΠΏΡΠΈ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΠΈ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΡΠ»Π΅ΠΊΡΡΠΎΠΌΠ°Π³Π½ΠΈΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠ»Ρ Π²ΠΎΠ·Π±ΡΠΆΠ΄Π΅Π½ΠΈΡ Π² Π·ΠΎΠ½Π΅ ΠΊΠΎΠ½ΡΡΠΎΠ»Ρ. Π¦Π΅Π»Ρ ΡΠ°Π±ΠΎΡΡ Π·Π°ΠΊΠ»ΡΡΠ°Π»Π°ΡΡ Π² ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠΈ Π°Π½Π°Π»ΠΈΠ·Π° Π½Π°ΡΡΠ½ΠΎ-ΡΠ΅Ρ
Π½ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΈ Π² ΠΎΠ±Π»Π°ΡΡΠΈ Π²ΠΈΡ
ΡΠ΅ΡΠΎΠΊΠΎΠ²ΠΎΠ³ΠΎ ΠΊΠΎΠ½ΡΡΠΎΠ»Ρ Π΄Π»Ρ ΠΈΠ·ΡΡΠ΅Π½ΠΈΡ ΡΠ²Π΅Π΄Π΅Π½ΠΈΠΉ ΠΎΠ± ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠΈ ΡΠ»Π΅ΠΊΡΡΠΎΠΌΠ°Π³Π½ΠΈΡΠ½ΡΡ
ΠΏΠΎΠ»Π΅ΠΉ Π²ΠΎΠ·Π±ΡΠΆΠ΄Π΅Π½ΠΈΡ Ρ Π°ΠΏΡΠΈΠΎΡΠΈ Π·Π°Π΄Π°Π½Π½ΡΠΌΠΈ ΡΠ²ΠΎΠΉΡΡΠ²Π°ΠΌΠΈ, Π° ΡΠ°ΠΊΠΆΠ΅ ΠΎΠ±ΠΎΠ±ΡΠ΅Π½ΠΈΡ, ΡΠΈΡΡΠ΅ΠΌΠ°ΡΠΈΠ·Π°ΡΠΈΠΈ Π½Π°ΠΊΠΎΠΏΠ»Π΅Π½Π½ΠΎΠ³ΠΎ ΠΎΠΏΡΡΠ° ΠΈ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄ΠΎΠ² ΠΊ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΈΡ ΡΠ΅ΠΎΡΠ΅ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ Π² Π΄Π°Π½Π½ΠΎΠΌ Π½Π°ΠΏΡΠ°Π²Π»Π΅Π½ΠΈΠΈ.ΠΡΠΎΠ²Π΅Π΄ΡΠ½ ΠΎΠ±Π·ΠΎΡ ΠΏΡΠ±Π»ΠΈΠΊΠ°ΡΠΈΠΉ Π² ΠΎΠ±Π»Π°ΡΡΠΈ Π½Π΅ΡΠ°Π·ΡΡΡΠ°ΡΡΠ΅Π³ΠΎ ΡΠ»Π΅ΠΊΡΡΠΎΠΌΠ°Π³Π½ΠΈΡΠ½ΠΎΠ³ΠΎ ΠΊΠΎΠ½ΡΡΠΎΠ»Ρ, ΠΏΠΎΡΠ²ΡΡΡΠ½Π½ΡΡ
ΡΠΎΠ²Π΅ΡΡΠ΅Π½ΡΡΠ²ΠΎΠ²Π°Π½ΠΈΡ ΡΠΈΡΡΠ΅ΠΌ Π²ΠΎΠ·Π±ΡΠΆΠ΄Π΅Π½ΠΈΡ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΉ Π²ΠΈΡ
ΡΠ΅ΡΠΎΠΊΠΎΠ²ΡΡ
Π΄Π΅ΡΠ΅ΠΊΡΠΎΡΠΊΠΎΠΏΠΎΠ². Π Π°ΡΡΠΌΠΎΡΡΠ΅Π½Ρ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄Ρ, Π² ΠΊΠΎΡΠΎΡΡΡ
ΠΎΠ΄Π½ΠΎΡΠΎΠ΄Π½ΠΎΠ΅ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ ΡΠ»Π΅ΠΊΡΡΠΎΠΌΠ°Π³Π½ΠΈΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠ»Ρ Π½Π° ΠΏΠΎΠ²Π΅ΡΡ
Π½ΠΎΡΡΠΈ ΠΎΠ±ΡΠ΅ΠΊΡΠ° ΠΊΠΎΠ½ΡΡΠΎΠ»Ρ Π΄ΠΎΡΡΠΈΠ³Π°Π΅ΡΡΡ Π»ΠΈΠ½Π΅ΠΉΠ½ΡΠΌ ΠΈ Π½Π΅Π»ΠΈΠ½Π΅ΠΉΠ½ΡΠΌ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΡΠΌ ΡΠΈΠ½ΡΠ΅Π·ΠΎΠΌ ΡΠΈΡΡΠ΅ΠΌ Π²ΠΎΠ·Π±ΡΠΆΠ΄Π΅Π½ΠΈΡ ΠΏΡΠΈ ΡΡΠ»ΠΎΠ²ΠΈΠΈ Π½Π΅ΠΏΠΎΠ΄Π²ΠΈΠΆΠ½ΠΎΡΡΠΈ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»Ρ ΠΎΡΠ½ΠΎΡΠΈΡΠ΅Π»ΡΠ½ΠΎ ΠΎΠ±ΡΠ΅ΠΊΡΠ° ΠΊΠΎΠ½ΡΡΠΎΠ»Ρ. ΠΡΠΎΠ²Π΅Π΄ΡΠ½ Π°Π½Π°Π»ΠΈΠ· ΠΊΠΎΠ½ΡΡΡΡΠΊΡΠΈΠΉ Π²ΠΈΡ
ΡΠ΅ΡΠΎΠΊΠΎΠ²ΡΡ
ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΉ Ρ ΠΎΠ΄Π½ΠΎΡΠΎΠ΄Π½ΡΠΌ ΠΏΠΎΠ»Π΅ΠΌ Π²ΠΎΠ·Π±ΡΠΆΠ΄Π΅Π½ΠΈΡ, ΡΠΎΠ·Π΄Π°Π½Π½ΡΠΌ ΠΊΡΡΠ³ΠΎΠ²ΡΠΌΠΈ, ΠΏΡΡΠΌΠΎΡΠ³ΠΎΠ»ΡΠ½ΡΠΌΠΈ ΡΠ°Π½Π³Π΅Π½ΡΠΈΠ°Π»ΡΠ½ΡΠΌΠΈ ΠΈ Π½ΠΎΡΠΌΠ°Π»ΡΠ½ΡΠΌΠΈ ΠΊΠ°ΡΡΡΠΊΠ°ΠΌΠΈ, Π° ΡΠ°ΠΊΠΆΠ΅ Π·Π° ΡΡΡΡ ΡΠΎΠ·Π΄Π°Π½ΠΈΡ Π²ΡΠ°ΡΠ°ΡΠ΅Π»ΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠ»Ρ Π²ΠΎΠ·Π±ΡΠΆΠ΄Π΅Π½ΠΈΡ. ΠΠ·ΡΡΠ°Π»ΠΈΡΡ ΠΊΠΎΠ½ΡΡΡΡΠΊΡΠΈΠΈ ΠΊΠ°ΡΡΡΠ΅ΠΊ Π²ΠΎΠ·Π±ΡΠΆΠ΄Π΅Π½ΠΈΡ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΉ Ρ ΠΏΠΎΠ»ΡΠΌΠΈ ΡΠ»ΠΎΠΆΠ½ΠΎΠΉ ΠΊΠΎΠ½ΡΠΈΠ³ΡΡΠ°ΡΠΈΠΈ, Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΠ·ΡΡΡΠΈΠ΅ΡΡ ΠΎΡΠΈΠ³ΠΈΠ½Π°Π»ΡΠ½ΠΎΠΉ ΡΡΠ°ΠΊΡΠ°Π»ΡΠ½ΠΎΠΉ Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΠ΅ΠΉ, ΠΊΠΎΡΠΎΡΡΠ΅ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡ ΡΠ²Π΅Π»ΠΈΡΠΈΡΡ Π²Π΅ΡΠΎΡΡΠ½ΠΎΡΡΡ Π²ΡΡΠ²Π»Π΅Π½ΠΈΡ Π΄Π΅ΡΠ΅ΠΊΡΠΎΠ², Π½Π΅ ΠΏΠΎΠ΄Π΄Π°ΡΡΠΈΡ
ΡΡ ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΡ ΠΊΠ»Π°ΡΡΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»ΡΠΌΠΈ.Π’Π°ΠΊΠΆΠ΅ ΠΏΡΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Ρ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ, Π² ΠΊΠΎΡΠΎΡΡΡ
ΠΏΡΠ΅Π΄Π»Π°Π³Π°Π΅ΡΡΡ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΠΏΠΎΠ»Π΅ΠΉ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΠΊΠΎΠ½ΡΠΈΠ³ΡΡΠ°ΡΠΈΠΈ Π² Π·Π°Π΄Π°Π½Π½ΠΎΠΉ Π·ΠΎΠ½Π΅ Ρ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΠ΅ΠΌ ΠΌΠ°Π³Π½ΠΈΡΠΎΠΏΡΠΎΠ²ΠΎΠ΄ΠΎΠ², ΠΊΠΎΠ½ΡΠ΅Π½ΡΡΠ°ΡΠΎΡΠΎΠ² ΠΏΠΎΠ»Ρ ΠΈΠ· ΠΏΡΠΎΠ²ΠΎΠ΄ΡΡΠΈΡ
ΠΌΠ°ΡΠ΅ΡΠΈΠ°Π»ΠΎΠ² ΠΈ ΡΠΊΡΠ°Π½ΠΎΠ² ΡΠΏΠ΅ΡΠΈΠ°Π»ΡΠ½ΠΎΠΉ ΡΠΎΡΠΌΡ. ΠΠ·ΡΡΠ°Π»ΠΈΡΡ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄Ρ ΠΊ ΡΠ΅Π°Π»ΠΈΠ·Π°ΡΠΈΠΈ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΠΈΠ½ΡΠ΅Π·Π° ΡΠΈΡΡΠ΅ΠΌ Π²ΠΎΠ·Π±ΡΠΆΠ΄Π΅Π½ΠΈΡ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΉ Ρ ΡΠ°Π²Π½ΠΎΠΌΠ΅ΡΠ½ΠΎΠΉ ΡΡΠ²ΡΡΠ²ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΡΡ Π² Π·ΠΎΠ½Π΅ ΠΊΠΎΠ½ΡΡΠΎΠ»Ρ Ρ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ ΡΡΡΡΠΎΠ³Π°ΡΠ½ΠΎΠΉ ΠΎΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΈΠΈ Π΄Π»Ρ ΡΠ»ΡΡΠ°Π΅Π² Π΄Π²ΠΈΠΆΡΡΠΈΡ
ΡΡ ΠΎΠ±ΡΠ΅ΠΊΡΠΎΠ² ΠΊΠΎΠ½ΡΡΠΎΠ»Ρ Ρ ΡΡΡΡΠΎΠΌ ΡΡΡΠ΅ΠΊΡΠ° ΡΠΊΠΎΡΠΎΡΡΠΈ. ΠΠ±ΠΎΠ±ΡΡΠ½ ΠΈ ΡΠΈΡΡΠ΅ΠΌΠ°ΡΠΈΠ·ΠΈΡΠΎΠ²Π°Π½ ΠΎΠΏΡΡ, Π° ΡΠ°ΠΊΠΆΠ΅ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΡΠ΅ΠΎΡΠ΅ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ, ΠΏΠΎΡΠ²ΡΡΡΠ½-Π½ΡΡ
ΠΏΡΠΎΠ±Π»Π΅ΠΌΠ΅ ΠΏΡΠΎΠ΅ΠΊΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π²ΠΈΡ
ΡΠ΅ΡΠΎΠΊΠΎΠ²ΡΡ
ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΉ Ρ ΡΠ°Π²Π½ΠΎΠΌΠ΅ΡΠ½ΠΎΠΉ ΡΡΠ²ΡΡΠ²ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΡΡ Π² Π·ΠΎΠ½Π΅ ΠΊΠΎΠ½ΡΡΠΎΠ»Ρ, ΠΎΠ±ΡΡΠ»ΠΎΠ²Π»Π΅Π½Π½ΠΎΠΉ ΠΎΠ΄Π½ΠΎΡΠΎΠ΄Π½ΡΠΌ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ΠΌ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ ΠΈΠ½Π΄ΡΡΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
ΡΠΎΠΊΠΎΠ², ΠΏΡΠΎΡΠ΅ΠΊΠ°ΡΡΠΈΡ
Π² ΠΎΠ±ΡΠ΅ΠΊΡΠ΅. ΠΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π° ΠΊΠ»Π°ΡΡΠΈΡΠΈΠΊΠ°ΡΠΈΡ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΉ ΠΏΠΎ ΡΡΠ΄Ρ ΠΏΡΠΈΠ·Π½Π°ΠΊΠΎΠ², Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΠ·ΡΡΡΠΈΡ
ΠΈΡ
ΡΠΈΡΡΠ΅ΠΌΡ Π²ΠΎΠ·Π±ΡΠΆΠ΄Π΅Π½ΠΈΡ
Magnetic Flux Leakage techniques for detecting corrosion of pipes
Oil and gas pipelines are subjected to corrosion due to harsh
environmental conditions as in refinery and thermal power plants. Interesting problems such as internal and external corrosion, emerging from the increasing demand for pipeline protection have prompted this study. Thus, early detection of faults in pipes is essential to avoid disastrous outcomes.
The research work presented in this thesis comprises investigations into the use of magnetic flux leakage (MFL) testing for pipe in extreme (underwater and high temperature) conditions. The design of a coil sensor (ferrite core with coil) with a magnetic circuit is carried out for high temperature conditions. The sensor thus developed lays the ground for non-destructive evaluation (NDE) of flaws in pipes through the MFL
technique. The research focusses on the detection and characterization of MFL distribution caused by the loss of metal in ferromagnetic steel pipes.
Experimental verifications are initially conducted with deeply rusted pipe samples of varying thicknesses in air. AlNiCo magnets are used along with Giant Magneto Resistance (GMR) sensor (AA002-02). The experiment is further repeated for saltwater conditions in relation to varying electrical conductivity with radio frequency identification (RFID) technique.
A further study carried out in the research is the correlation between magnetic and underwater data communication. The study has resulted in the development and experimental evaluation of a coil sensor with its magnetic response at room and high temperatures. This makes the system effective under high temperature conditions where corrosion metal loss needs to be determined
Magnetic Flux Leakage techniques for detecting corrosion of pipes
Oil and gas pipelines are subjected to corrosion due to harsh
environmental conditions as in refinery and thermal power plants. Interesting problems such as internal and external corrosion, emerging from the increasing demand for pipeline protection have prompted this study. Thus, early detection of faults in pipes is essential to avoid disastrous outcomes.
The research work presented in this thesis comprises investigations into the use of magnetic flux leakage (MFL) testing for pipe in extreme (underwater and high temperature) conditions. The design of a coil sensor (ferrite core with coil) with a magnetic circuit is carried out for high temperature conditions. The sensor thus developed lays the ground for non-destructive evaluation (NDE) of flaws in pipes through the MFL technique. The research focusses on the detection and characterization of MFL distribution caused by the loss of metal in ferromagnetic steel pipes.
Experimental verifications are initially conducted with deeply rusted pipe samples of varying thicknesses in air. AlNiCo magnets are used along with Giant Magneto Resistance (GMR) sensor (AA002-02). The experiment is further repeated for saltwater conditions in relation to varying electrical conductivity with radio frequency identification (RFID) technique.
A further study carried out in the research is the correlation between magnetic and underwater data communication. The study has resulted in the development and experimental evaluation of a coil sensor with its magnetic response at room and high temperatures. This makes the system effective under high temperature conditions where corrosion metal loss needs to be determined
Eddy current defect response analysis using sum of Gaussian methods
This dissertation is a study of methods to automatedly detect and produce approximations of eddy current differential coil defect signatures in terms of a summed collection of Gaussian functions (SoG). Datasets consisting of varying material, defect size, inspection frequency, and coil diameter were investigated. Dimensionally reduced representations of the defect responses were obtained utilizing common existing reduction methods and novel enhancements to them utilizing SoG Representations. Efficacy of the SoG enhanced representations were studied utilizing common Machine Learning (ML) interpretable classifier designs with the SoG representations indicating significant improvement of common analysis metrics
Challenges in improving the performance of eddy current testing: Review
Eddy current testing plays an important role in numerous industries, particularly in material coating, nuclear and oil and gas. However, the eddy current testing technique still needs to focus on the details of probe structure and its application. This paper presents an overview of eddy current testing technique and the probe structure design factors that affect the accuracy of crack detection. The first part focuses on the development of different types of eddy current testing probes and their advantages and disadvantages. A review of previous studies that examined testing samples, eddy current testing probe structures and a review of factors contributing to eddy current signals is also presented. The second part mainly comprised an in-depth discussion of the lift-off effect with particular consideration of ensuring that defects are correctly measured, and the eddy current testing probes are optimized. Finally, a comprehensive review of previous studies on the application of intelligent eddy current testing crack detection in non destructive eddy current testing is presented
An electromagnetic imaging system for metallic object detection and classification
PhD ThesisElectromagnetic imaging currently plays a vital role in various disciplines, from engineering to medical applications and is based upon the characteristics of electromagnetic fields and their interaction with the properties of materials. The detection and characterisation of metallic objects which pose a threat to safety is of great interest in relation to public and homeland security worldwide. Inspections are conducted under the prerequisite that is divested of all metallic objects. These inspection conditions are problematic in terms of the disruption of the movement of people and produce a soft target for terrorist attack. Thus, there is a need for a new generation of detection systems and information technologies which can provide an enhanced characterisation and discrimination capabilities.
This thesis proposes an automatic metallic object detection and classification system. Two related topics have been addressed: to design and implement a new metallic object detection system; and to develop an appropriate signal processing algorithm to classify the targeted signatures. The new detection system uses an array of sensors in conjunction with pulsed excitation. The contributions of this research can be summarised as follows: (1) investigating the possibility of using magneto-resistance sensors for metallic object detection; (2) evaluating the proposed system by generating a database consisting of 12 real handguns with more than 20 objects used in daily life; (3) extracted features from the system outcomes using four feature categories referring to the objectsβ shape, material composition, time-frequency signal analysis and transient pulse response; and (4) applying two classification methods to classify the objects into threats and non-threats, giving a successful classification rate of more than 92% using the feature combination and classification framework of the new system.
The study concludes that novel magnetic field imaging system and their signal outputs can be used to detect, identify and classify metallic objects. In comparison with conventional induction-based walk-through metal detectors, the magneto-resistance sensor array-based system shows great potential for object identification and discrimination. This novel system design and signal processing achievement may be able to produce significant improvements in automatic threat object detection and classification applications.Iraqi Cultural AttachΓ©, Londo
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