Suppression of Additive Periodic Low-Frequency Interference on Eddy-Current Defectograms

To identify and predict risks in the work, a method for assessing traffic safety in railway transport is proposed. On the basis of statistics on the failure of freight cars during operation, the characteristic distribution laws for types of wear were determined. As a result, the dependences of the probability of failure-free operation of freight cars on the operating life were obtained and the centers of gravity of the areas that are used to characterize and assess the risk were determined. When designing a freight car, it is possible to establish risk values obtained on the basis of statistical data, which opens up the possibility of improving traffic safety in railway transport. In the developed method for assessing traffic safety in railway transport, the use of a graphical risk matrix is proposed. It is also proposed to combine the dependencies of the probability of failure-free operation of freight cars to calculate the total risk. This allows you to get a graphical risk matrix taking into account three types of wear of a freight car to assess traffic safety. The number of dependencies of the probability of failure-free operation of freight cars can be increased if failures are observed for other reasons.

A ship uses four Sabroe 163 units and two Sabroe 128 units as the chiller for the general and special air conditioning systems. After ten years of operation and use, it entered the overhaul. It is planned to determine the damage condition of the heat exchanger tubes of the evaporator and the condenser by eddy current method to determine the next maintenance plan. Due to the ship’s docking overhaul, the eddy current flaw detection has been equipped with conditions for draining the equipment, cleaning the heat exchange tubes, purging the inner wall of the heat transfer tubes, and drying. This eddy current testing was performed by a maintenance engineer using a dedicated device that was calibrated.

Eddy Current Array Inspection of Zlin 142 Fuselage Riveted Joints

This paper describes the use of an eddy current testing (ECT) method for the inspection and detection of impact damage in carbon fiber-reinforced composites (CFRP). ECT method is a nondestructive testing (NDT) method where electric induction is used. This method is widely used for detecting cracks and corrosion in metals, or checking their electric conductivity. Because carbon fiber in CFRP has electric conductivity, ECT method has a potential to inspect the defects. However, electric conductivity of CFRP is much smaller than that of metals. Moreover, from the view of the eddy current probe, CFRP to be checked looks as a inhomogeneous conductive materials where conductive fibers are bundled and laid up, and this is completely different situation comparing with metal samples that are homogeneous. Therefore, there are several problems to be solved for applying ECT method to CFRP such as proper selection of test frequency, shape of probe, or signal processing.

Sensors’ signal conditioning and digital interface are important for sensor technologies, digital transformation, and the Internet of Things (IoT) in particular. Frequency output sensors and inductance-to-digital converters (LDC) offer distinct advantages over Analog-to-Digital Converter (ADC) interfaces. To miniaturize the eddy current testing system and achieve multi-parameter measurements, this paper reviews eddy current signal conditioning and digital interfaces in the field of displacement sensors and non-destructive tests & evaluation (NDT&E). After review and comparison of different signal conditioning and digital interfaces, the LDC chip is used in eddy current testing for multiple parameter measurements including lift-off distance and defect detection. An LDC-based integrative eddy current non-destructive testing method is proposed. The LDC chip provides AC to drive the LC resonator composed of the sensor coil and the parallel capacitor. By measuring the resonance frequency and parallel resistance (Rp) of the LC resonator, the simultaneous measurement of the lift-off distance and the defect is achieved. Based on the method, the testing experiments of two kinds of specimens made of aluminium and steel were carried out under different lift-offs. Experimental results show that both parameters of frequency and Rp of the LC resonator can intuitively reflect the defect depth and lift-off. Frequency- Rp curves can be used to quantify defect depth and lift-off distance and differentiate the material. This work also illustrates an integrated approach of signal conditioning and digital interface for multiple parameters or feature measurement for integrated eddy current NDT&E. The work opens a new way for addressing multiple parameter measurements of eddy current NDT & E including lift-off estimation and defect characterization via digital interfaces. It has the potential to bridge the gaps in metrology of geometry, displacement measurement, and NDT&E for defect detection and material characterization.

Eddy current testing is considered a theoretically challenging technique. Out of all the different nondestructive testing (NDT) methods, the electromagnetic testing (ET) method (of which eddy current testing is a technique) is probably the most difficult for understanding theory. This is perhaps why the last Materials Evaluation Back to Basics paper on eddy current testing is from 2006, which is a long time ago given the amount of innovation in the technique that has taken place since then (Hansen and Peoples 2006). In this paper we will show what has changed due to recent innovations. We first will present the physics, and then explain how modern equipment assists the user in distinguishing between different physical phenomena. Although this paper is on conventional eddy current testing, we will also mention some other ET techniques along with their advantages and disadvantages.

Eddy current testing is an important and widely used method in non-destructive testing and evaluation. In this paper, an impedance analysis model of eddy current testing based on mutual inductance equivalent circuit is established using transmission line theory, and an analytical expression of impedance of the testing workpiece is obtained. Then the changes of impedance plane of ECT sensor affected by such as the thickness, the conductivity of the tested workpiece and the lift-off are studied. Experiment results are consistent with the theoretical analysis, which proves the validity of the model. All the conclusions derivated by the model can be helpful for eddy current testing optimization. This electronic document is a “live” template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document.

Eddy current testing is a nondestructive testing method, which is used to detect discontinuities and defects in conductive materials. Using this technique, two different types of artificial defects in a railhead were evaluated in order to analyze the relationship between different types of defects and eddy current signals, and to obtain data on the size of the rail surface defects and crack location. The actually used rail sample was also studied. Surface cracks and defects were clearly observed as amplitude and phase changes of detected signals. This study succeeds in quantitatively analyzing and discriminating the damage types.

A large number of carbon fiber reinforced polymers have been applied to aircraft and automobiles, and many nondestructive testing methods have been studied to detect their defects. Eddy current magneto-optical imaging nondestructive testing technology has been widely used in the detection of metal materials such as aircraft skin, but it usually requires a large excitation current and, at present, can only detect metal materials with high conductivity. In order to take full advantage of the innate benefits and efficiency of eddy current magneto-optic imaging and enable it to detect defects in carbon fiber reinforced polymers with weak conductivity, it is necessary to improve the magnetic field response of the eddy current magneto-optic imaging system and explore suitable excitation and detection methods. The scanning eddy current magneto-optical imaging nondestructive testing device built in this study has improved the magnetic field response of the system, and the eddy current magneto-optical phase imaging testing method has been proposed to detect the crack defects of carbon fiber reinforced polymers. The effectiveness of the method has been verified by simulation and experiment.

For automaic inspection of wire rod in hot rolling, non-contact diameter gauge and eddy current flaw detector have been developed and installed at Daido's Chita plant.The former is opt-electronic type, using silicon cell array and its precision is ±0.03mm in-line use.The latter is anual coil type and is able to detect the small flaw as 0.1mm depth. These equipments is applicable to the diameter range of wire rod from 7mm to 32mm, and one set of these equipments has been installed for small diameter wire rod (7mm∼15mm), the another set for large diameter wire rod (16mm∼32mm).To keep good stable ability in-line, many partial improvement are done.

Background. The relevance of the study is due to the increasing demands on the reliability and safety of railway transport. Modern railway automation and telemechanics systems are elaborate technical complexes, the failure of which can lead to significant economic losses and disruption of the movement schedule. Traditional reliability assessment methods based on the analysis of single indicators do not allow for a comprehensive assessment of the condition of such systems. The existing methodological vacuum in the area of integrated assessment of the railway automation and telemechanics availability systems determines the need to develop new approaches that take into account the multi-criteria nature of the task and allow aggregating heterogeneous indicators within a single assessment. Purpose. Methodology development for the integral assessment of the levels of readiness of technical support for railway systems based on mathematical modeling and the Harrington desirability function, which allows for a comparative analysis of railway infrastructure facilities and substantiate management decisions in the area of maintenance and modernization. Materials and methods. The research is based on the application of the Semimarkov process apparatus for modeling the reliability of railway automation and telemechanics systems. The mathematical model includes six system states that take into account various stages of the equipment lifecycle. The Harrington desirability function was used to transform heterogeneous reliability indicators into a single integrated assessment, providing a transition to a dimensionless measurement scale. Results. A method for the integral assessment of the levels of readiness of harvest systems has been developed, combining mathematical modeling based on semi-Markov processes with the transformation of indicators by the Harrington function. An analysis of failure statistics for 2018-2023 revealed a steady downward trend in the number of failures across all categories of equipment. Practical testing of the methodology at ten railway stations made it possible to identify problem areas and determine maintenance priorities. The implementation of the resource allocation algorithm based on game theory has shown the possibility of increasing the efficiency of using funds by 15% compared with uniform allocation. The largest share of resources (47.8%) is appropriate for safety control systems as the most critical for traffic safety. The developed models have shown adequacy in predicting changes in the integral readiness indicator.

Remote-field eddy current (RFEC) testing is a nondestructive testing method. It has been comprehensively applied to detect wall loss in ferromagnetic tubes. According to our experience, the problem of variations in a material's electromagnetic characteristics often occurred in practice in carbon steel tubes. Therefore, if we fail to compensate for changes in electromagnetic characteristics during inspection, an error of evaluation will be generated. This study applied the skin-depth theory of RFEC and geometric relationships on the voltage plane to derive a compensatory model using a mathematical methodology. The new evaluation curve established on the basis of this mathematical methodology compensates for the error contributed by changing electromagnetic characteristics in the tube. The method offered by this study has proved to be reasonable, feasible and acceptable in terms of its mathematical derivation and in comparison with experimental result.

NON-DESTRUCTIVE TESTING (NDT) utilizes the physical properties of a material for detection, location and evaluation of flaws/defects and judging of the microstructure and mechanical properties without damaging the functionality of component being inspected. Flaws or imperfections that are detected by inspection of the component may be obtained by several reasons. It may be due to originality of the material caused by the process used created by some human error or defects initiated during the operating life of components etc. NDT method ranges from the simple to the tangled. NDT is also used for condition monitoring of various components during operation to forecast and assess the rest of the life of components while retaining its structural integrity. Based on availability, accessibility, suitability, analysis and experience the choice of specific method varies. The end result is the saving of time, money and development in precision and reliability of results obtained. There are a vast number of techniques in NDT. Visual inspection testing, liquid penetrate testing, ultrasonic testing, magnetic particle testing, eddy current testing, thermal infrared testing, acoustic emission, leak testing, thermography, instinct metallographic examination. The industrial applications of NDT are mostly found in railways, nuclear, non – nuclear and chemical industries, aircraft and petroleum projects, coal mining industry. This paper presents the knowledge for selection of specific NDT detecting surface flaws and requisite applications. It presents vital aspects in each method along with their advantages and disadvantages.

It is difficult for traditional magnetic flux leakage (MFL) methods to detect inner surface cracks of thick-walled steel pipe or plate due to magnetic shielding of the wall and strong magnetic background noise, and for eddy current testing (ECT) as well due to its skin effect. On the basis of the nonlinear magnetic permeability of ferromagnetic materials, a new non-destructive testing method (NDT) permeability-measuring magnetic flux leakage (P-MFL) is proposed, in which the magnetization is perpendicular to the inner surface crack, and the surface layer permeability distortion caused by magnetic field distortion is measured by differential pick-up coils. Afterwards, its detection mechanism is presented and analyzed, and its feasibility is verified by simulations and experiments. Finally, some application cases for steel pipe are also realized effectively. Meanwhile, its testing characteristics for cracks are given and effects of crack size, specimen thickness, scanning paths to testing signal amplitude are briefly analyzed. Finally, the proposed P-MFL method compared to traditional MFL method is discussed in detail.

This paper critically considers attempts to prove the frequency dependences of the electrical conductivity and magnetic permeability of metals at frequencies lower than 1 MHz. Such attempts were made by certain authors when studying the operation of eddy-current transducers. It is shown that the complex character of the output voltage of an eddy-current transducer is determined by the vector summation of the magnetic fluxes of the primary magnetizing alternating field and the field of eddy currents, which are induced by the primary field, in a tested article. The frequency dependence of the results of this summation is quite sufficient for a physically correct description of the operation of an eddy-current transducer without involving a hypothesis on the frequency dependence of the physical constants of the material of the tested article.