Nondestructive Testing Devices Research Articles

Number of concrete strength tests using the elastic rebound method

The article discusses the determination of the required number of experiments when determining the compressive strength of concrete using the elastic rebound method. It is shown that it is not correct to accept a deterministic value for the minimum number of experiments for all grades (classes of concrete). This value depends on the average strength of concrete and the instrument error of the device used. For a given coefficient of variation, with increasing concrete strength, the required number of experiments increases. For the maximum permissible coefficient of variation of concrete strength of 13.5%, calculated dependences of the minimum number of experiments on the average strength of concrete were obtained for the minimum and maximum instrumental errors of the sclerometers used, determined by analyzing the passport data used in Russian organizations involved in the inspection of buildings and structures. The proposed method, which relates the strength of the material of the structure under study and the instrumental error of the device used, can be extended to other methods of determining strength by non-destructive methods and can be the basis of the technical specifications for the creation of devices for non-destructive testing of concrete.

Modernization the system of periodic control for the concrete properties

Periodic control of concrete properties is based on the use of nondestructive methods. Periodic monitoring of the condition of structures often is performed using ultrasonic devices. The accuracy of determining the physical and mechanical characteristics (FMC) of concrete depends on a significant number of factors affect. This reduces the accuracy of the results by standard methods. Based on previous studies, the methodology for using ultrasonic non-destructive testing devices was improved. The research and verification of the improved methodology in a real building demonstrate the low complexity of the work and sufficient reliability of the results. Improvement of the algorithm for work and data processing will allow to offer a reliable methodology for determining the technical condition of the operated structures and for periodic monitoring the concrete properties. A methodology for periodic monitoring of concrete properties in structures has been developed. It is necessary to carry out.

Evaluating the strength properties of standing trees through fractometry

In recent years, significant advancements in non-destructive testing (NDT) methodologies have emerged, with applications spanning various domains, including structural wood quality assessment and planted tree characteristic evaluation. Within the context of planted trees, a range of non-destructive and semi-destructive techniques have been developed to assess the extent of degradation in tree trunks. In this study, various mechanical characteristics of brutian pine (Pinus brutia Ten.) trees near the Ertokuş Madrasah in the Atabey district of the province of Isparta are examined. Beside their historical significance, these trees are notable for the potential risk they present in terms of leaning towards the madrasah facade and the risk of falling over. To achieve the goals of research, the resistance characteristics of incremental cores were systematically determined by using a thermal imaging camera in conjunction with a portable, non-destructive testing device called a Fractometer. Totally 15 incremental auger specimens were obtained by extracting three increment core samples, each with a thickness of 5 mm, from the trunks of five distinct trees, all at a consistent height of 1.3 meters above ground level. Bending and compressive strength measurements were recorded at intervals of 6 mm from the core to the outermost layer. Furthermore, the moisture content of the incremental cores was assessed using thermal imaging technology. Following an analysis of the collected data, it was concluded that the mechanical properties of the investigated brutian pine trees within an acceptable range.

Development and testing of a device for non-destructive testing of hard alloys

THE RELEVANCE of the work lies in the need to control the cutting inserts of metalworking tools, which are widely used today in production and used in the machining of products for various purposes in mechanical engineering. The production of carbide plates involves a number of operations: obtaining fine powders, mixing them in certain proportions, shaping, followed by pressing and sintering. Violation of the technology of at least one of the considered operations leads to the production of defective plates, the quality of which does not meet the requirements. The use of such plates in production leads to the production of defective products or an increase in the complexity of their manufacture, which is associated with the need for their frequent replacement. Traditional control methods have a significant drawback - the destruction of the product or its damage. They can be avoided using non-destructive testing methods, which include the coercive force method. The authors proposed a device of an original design, which makes it possible to implement non-destructive testing of the considered products made of hard alloys of various grades. To test its performance, a prototype was developed and tested. THE PURPOSE. Development of a device for non-destructive testing of products made of hard alloys and its testing in order to determine the relative error. The task is relevant, since there is a need for enterprises to control the quality of replaceable carbide inserts of metalworking tools. METHODS. During testing of the device, generally accepted empirical research methods were used, and the determination of the relative error was carried out according to the methodology developed for the Koerzimat 1.097 HcJ coercimeter, as well as using generally accepted methods of mathematical statistics. RESULTS. The electrical structural and principal diagrams of the device have been developed, and its design parameters have been determined. Tests of the device were carried out, during which measurements of the coercive force were made for samples made of various grades of hard alloys and having different shapes and sizes. CONCLUSION. The design of the developed device is characterized by simplicity and low cost; at the same time, it is based on a modern element base. The test results of the device showed that the relative measurement error is within acceptable limits, which allows it to be used to control products made of hard alloys in production conditions.

Direct-Ink-Writing Printed Strain Rosette Sensor Array with Optimized Circuit Layout

The full-field multiaxial strain measurement is highly desired for application of structural monitoring but still challenging, especially when the manufacturing and assembling for large-area sensing devices is quite difficult. Compared with the traditional procedure of gluing commercial strain gauges on the structure surfaces for strain monitoring, the recently developed Direct-Ink-Writing (DIW) technology provides a feasible way to directly print sensors on the structure. However, there are still crucial issues in the design and printing strategies to be probed and improved. Therefore, in this work, we propose an integrated strategy from layered circuit scheme to rapid manufacturing of strain rosette sensor array based on the DIW technology. Benefit from the innovative design with simplified circuit layout and the advantages of DIW for printing multilayer structures, here we achieve optimization design principle for strain rosette sensor array with scalable circuit layout, which enable a hierarchical printing strategy for multiaxial strain monitoring in large scale or multiple domains. The strategy is highly expected to adapt for the emerging requirement in various applications such as integrated soft electronics, nondestructive testing and small-batch medical devices.

Nonlinear elastic vector solitons in hard-magnetic soft mechanical metamaterials

We propose a design of a metamaterial for magnetically tunable propagation of nonlinear vector solitary waves. The metamaterial consists of a periodic array of units of hard-magnetic inclusion embedded in a soft matrix. The units are connected via thin and highly deformable ligaments. Our theoretical and numerical modeling results show that the configuration of the metamaterial undergoes drastic transformations when activated by a magnetic field. These controllable microstructural transformations significantly influence the propagation of vector solitary waves in the proposed metamaterial system. We report the magnetic field-enabled propagation of solitary waves. We show that the proposed soft magnetoactive metamaterial allows us to tune the key characteristics of the enabled nonlinear solitary waves, including their pulse width and amplitude. Our findings also highlight the potential of magneto-mechanical coupling in the development of untethered mechanical metamaterial systems for applications in nondestructive testing, energy harvesting, and smart soft wave devices.

A Non-destructive Radar Device for Detecting Additive Materials in Concrete

The use of electronic devices based on electromagnetic waves is promising for inspecting additives in structural concrete. However, the existing commercial devices are high-cost and do not publicly provide circuit design information. To overcome this issue, this study designed a low-cost nondestructive testing device with a radar sensor, using an HB-100 radar sensor module to generate and receive the radar wave. A suitable bandpass filter was used to suppress electrical noise in the received signal, an Arduino board was used for signal processing, and the measured data were displayed on a computer. The output at the IF pin of the sensor module presents the Doppler frequency and absorbance of the target materials. The device was tested to detect additives inside the concrete. An additive material can be recognized by the fact that the obtained signal magnitudes are different with different additive materials. The findings in this study can contribute to making a low-cost nondestructive testing device based on radar technology for structural concrete inspection.

Improving Magnetic Field Response of Eddy Current Magneto-Optical Imaging for Defect Detection in Carbon Fiber Reinforced Polymers

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.

Research on Improvement of Clamping Device for Online Nondestructive Tensile Testing of Braided Wire Rope

The online nondestructive tensile testing machine can crush wire ropes, during the safety tension test of braided wire ropes. To solve this problem, this paper analyzes the reasons for crushing phenomena from the aspects of static simulation and geometric analysis of wire ropes. In terms of static simulation of the tensile process, the equivalent stress, contact pressure and contact gap cloud map of the wire rope in the clamping jaw range are obtained. It is found that both equivalent stress and contact pressure of the wire rope reach maximum values at the transition section between the adjacent peak and trough of the sinusoidal curve, while both reach minimum values at the position of the peak and trough, where the wire rope is in a non-contact state. Concerning the geometrical analysis of the clamping surface of the jaws, the results show that the normal distance between the sinusoidal curves of the movable jaw and the fixed jaw is not constant in one period, which is the smallest at the transition section between the peak and the trough. Therefore, our group determine the destruction resulted from the unreasonable curve shape of the clamping surface, further improve the jaw curve and realize the non-damaged safety tension test of wire ropes.

USE OF MAGNETIC NON-DESTRUCTIVE TESTING TO EVALUATE THICKNESS OF CONCRETE PROTECTIVE LAYER FOR ENCLOSING AND BEARING STRUCTURES AT NPP

Introduction. This article discusses methods and means of controlling the diameter and position of reinforcement and the thickness of the concrete protective layer, along with the contemporary techniques and devices for diagnostic and non-destructive testing of concrete. A comparative analysis of the applicability of contemporary devices was carried out.Aim. In this work, magnetic non-destructive testing was used to assess the thickness of the concrete protective layer, along with establishing the location of the upper row of rod reinforcement and embedded parts. Based on analyzing the interaction between the electromagnetic field of the sensor and the electromagnetic field of eddy currents induced by the source coil of the sensor in rebar, this method allows the diameter of the latter to be approximately estimated at an unknown protective layer.Materials and methods. As an example, the thickness of the concrete protective layer of enclosing structures (walls, floors) at power unit № 1 at the Kalinin Nuclear Power Plant (NPP) was measured using the POISK-2.6 device.Results. The analysis of design and as-built drawings for buildings and structures of the main facility of power unit № 1 at the Kalinin NPP was carried out. The state of passive fire protection equipment at the power unit (fire doors, cable penetration seals, and ventilation fire dampers) was evaluated. The actual thickness of the concrete protective layer and the location of the reinforcement of concrete elements at the facilities of the Kalinin NPP power unit were measured as per GOST 22904-93 using electromagnetic NDT. The applicability of the magnetic NDT for determining the thickness of the concrete protective layer was shown during the inspection of building structures.Conclusions. During the inspection of the facilities, it was established that the average thicknesses of the concrete protective layer, including the thickness of the reinforcement, range from 38 to 85 mm, with the diameter of the reinforcement of 12–20 mm. During the measurements, the applicability of the method was shown; it was also confirmed that the examined structures exhibit fire endurance of at least 90 minutes, which meets the requirements of regulatory documents.

Increasing the Accuracy Characteristics of Focused Electromagnetic Devices for Non-Destructive Testing and Technical Diagnostics by Implementing Sum–Difference Signal Processing

Nowadays, the classical aperture theory is supplemented by data on the properties of electromagnetic fields in the near radiated field zone. A fundamental feature of the functioning of antennas in this area is the possibility of spatial focusing of electromagnetic energy. In this case, it is possible to realize the maximum field strength at a given point in space and reduce the field strength outside this point. The focusing effect itself is provided by the in-phase addition of fields from elementary sources. Also, in addition to the formation of the maximum field strength at the focusing point, it is also possible to realize a minimum field strength at the focusing point by implementing antiphase addition of partial fields at the focusing point. The fundamental possibility of forming sum and difference amplitude distributions of electromagnetic fields in the near radiated field zone makes it possible to realize sum–difference signal processing in order to reduce the level of the secondary maximum of the focused field. This article discusses the features of the formation of the sum and difference amplitude distributions and the principles of the sum–difference processing of focused electromagnetic fields, along with the implementation of technical solutions for non-destructive testing and technical diagnostic tasks.

Development of Non-Destructive Testing Device for Plant Leaf Expansion Monitoring

This paper designs a plant leaf expansion pressure non-destructive detection device, aiming to promote plant leaf expansion pressure research and achieve precision irrigation. The design is based on leaf expansion pressure probe technology, which can effectively monitor the plant leaf expansion pressure by detecting the feedback of the leaf under constant pressure. In this paper, the stability of the sensor and the calibration model is tested. The calibration experiments showed that the coefficient of determination R2 of the sensor was over 0.99, the static test results showed that the range of the sensor was 0–300 kPa, and the fluctuation of the sensor was less than 0.2 kPa during the long-term stability test. The indoor comparison tests showed that there was a significant difference in the variation of leaf expansion pressure data between plants under drought conditions and normal conditions. The irrigation experiments showed that the leaf expansion pressure was very sensitive to irrigation. The correlation between the expansion pressure data and the environmental factors was analyzed. The correlation coefficient between expansion pressure and light intensity was found to be 0.817. The results of the outdoor experiments showed that there was a significant difference in the expansion pressure of plants under different weather conditions. The data show that the plant leaf expansion pressure non-destructive detection device designed in this paper can be used both as an effective means of detecting plant leaf expansion pressure and promoting the research of plant physiological feedback mechanisms and precision irrigation.

The influence of skills in working with ultrasonic devices on the sustainable development of the quality of control of test results

This article deals with the problem of taking into account the level of proficiency of ultrasonic non-destructive testing devices by construction control specialists for the sustainable development of test quality. In the process of conducting input control operations of structural materials entering the construction site, there is a need for their detailed verification using non-destructive testing devices. At the same time, the results obtained with the help of portable ultrasound monitoring devices may differ from one specialist to another. This fact may call into question the regulatory organizations that accept and analyze the results of these tests. This study presents the results of ultrasonic testing of various building materials. The main feature of the study is that measurements are carried out by different people using a single calibrated ultrasound device. The introductory part of the article describes the formulation of this problem in the industry and the need to find solutions. The Methods section describes the applied methods and experimental conditions. In the discussion section, the question of the need for further more detailed studies of the problem of using non-destructive testing methods for the sustainable development of the quality of tests performed will be raised. As a result of the conducted research, a generalized analysis of the information received was carried out, conclusions and recommendations were formulated.

Train Wheel Magnetic Flux Leakage Testing Method Based on Local Magnetization Enhancement

Non-destructive testing (NDT) of train wheels fatigue cracks is a critical technology to ensure railway safety. Early fatigue cracks are small and difficult to detect. In this paper, the magnetic flux leakage (MFL) method is proposed to detect train fatigue cracks. The unsaturated magnetization state near the defect area is revealed through magnetic circuit analysis and finite element methods. As a result, leakage magnetic fields will decay sharply for small fatigue cracks, and they are difficult to detect by the traditional MFL method. To improve the magnetization state near defect areas, a novel MFL method based on local magnetization enhancement is proposed and developed. Experimental verification is also conducted by a train wheel NDT device. Testing results show that this method achieves excellent performance in the detection of defects in train wheels.

Диагностика с помощью приборов неразрушающего контроля железобетонной облицовки и грунтового основания для оценки технического состояния дамбы Крюковского водохранилища

Purpose: to perform diagnostics using non-destructive testing devices for reinforced concrete lining and soil foundation of the Kryukovskoe reservoir dam for its technical condition assessment. Materials and methods. The materials for the study were the data of a visual survey of the Kryukovskoe reservoir, the hazardous areas, where the instrumental control by non-destructive methods was performed, were identified. Later the hazardous areas were examined in detail for the presence of defects and damage. In the course of research, an instrumental survey of the reinforced concrete lining of the Kryukovskoe reservoir was carried out in problem areas 12 km long by the Oko-3 georadar. When processing the obtained data, there is a possibility of three-dimensional visualization of the parameters of the medium under study and the attributes of the wave field. At the same time, the soil foundation of the dam was surveyed by a high-frequency detector Nokta Invenio Smart, in real time using the functions of a geoscanner, a three-dimensional model of the studied section of the soil foundation is modelled, displaying the geometric characteristics of hidden cavities and soil softening. Results. Diagnostics of the technical condition of the reinforced concrete lining and soil foundation of the dam of the Kryukovskoe reservoir was performed. The abutments of earthen structures to concrete ones, the state of temperature-settlement joints of concrete and reinforced concrete structures that could affect stability were examined. Radargrams of soil foundation subsidence locations, formed as a result of the accident and removed during the dam reconstruction, were obtained. Conclusions. On the basis of the conducted studies it was defined that the reinforced concrete lining of the reservoir dam is, in general, in a satisfactory condition and serves its functional purpose. Diagnostics of the dam foundation showed the need to strengthen the stability of the structure.

A method and apparatus for inspecting large flat composite parts by using the Infrared LST technique

The principle of Line Scan Thermography (LST) was used to develop a self-propelled infrared thermographic nondestructive testing device for the inspection of large, relatively flat composite aerospace parts, such as aircraft wings. The design of the unit allowed the suppression of noise from reflected radiation. The new equipment, using the LST method, provided defect detectability similar to that achieved with a classic, static, flash heating procedure, but with a higher rate of testing. Also, the line heating principle ensured more uniform thermal patterns, and the proper choice of scan speed and field of view allows the selection of optimal time delays and the creation of maps of defects at different depths. Defect characterization efficiency was improved by using a trained neural network.

NDE 4.0 Paradoxical Results of a Decade

In November 2011, the government and business of Germany approved the INDUSTRIE 4.0 strategic initiative aimed at developing industrial information technologies and establishing itself as a world leader in the field of industry, primarily mechanical engineering, as the basis of a modern economy. Ten years have passed, it has already been forgotten that this is a national project of one specific country. The English-language "INDUSTRY 4.0" and the number 4.0 itself have become global brands. The need to integrate methods, technologies and equipment into smart distributed processes of design, production and maintenance of products has formed a new area of knowledge NDE 4.0 about physical methods and devices for detecting inhomogeneities in materials and products, as well as determining their geometric and physical and mechanical characteristics in order to quantify their structural integrity and compliance with the specified design parameters using the main technical ideas and principles of INDUSTRY 4.0 (including the unified principles of standardization and metrological support), which allow optimal integration of non-destructive testing devices and systems into the CPS structure and "smart industries" to ensure full automation of all production and management processes. It has been ten years of research and development. The public and behind-the-scenes statements of the publication dedicated to this anniversary are not as enthusiastic as in the first years of the project's deployment. As it seems to the author, this is largely due to the lack of a correctly formulated strategy and unity of goals involved in the process of specialists from various industries and understanding of NDE 4.0 as an interdisciplinary scientific and technical direction aimed at building networks of connected intelligent sensors that form large systems built into the infrastructure of distributed "smart" enterprises / industries, the development of related engineering disciplines as the basis for ensuring the autonomous long-term functioning of these systems based on realistic models of NDT and CM tools built into robotic systems using deep / machine learning with the subsequent implementation of the principles of artificial intelligence in NDT and CM, taking into account trends INDUSTRY 4.0, as well as solving problems related to the transition from automated to automatic NDT within the full life cycle of complex technical systems. In the report: - analyzed the main tasks and forecasts in the field of development of methods, equipment and technologies of NDT and CM, as well as the training of specialists at time intervals of 5, 10 and 20 years, starting from 2012, their connection with the goals and objectives of the INDUSTRIE 4.0 initiative; - slippages of NDE 4.0, connected, among other things, with similar problems of INDUSTRIE 4.0, were identified and justified; - critically examined the paradox of "near-zero progress in efficiency in the field of NDE 4.0 practice, which seems close to the" Salou paradox "; - in relation to NDE 4.0, a hypothesis is stated about the need for a significant time lag (delay) between the moment of development and widespread introduction of new planetary digital technologies and the appearance of large-scale breakthrough results; - the need for a comprehensive consideration of the NDE 4.0 and INDUSTRIE 4.0 factors is shown, related to the fact that new technologies make it possible to change production methods with embedded NDT and CM technologies, mechanisms for distributing and consuming the created values, but do not directly affect economic results; - the reasons for the considered paradoxes are systematized, including the fact that the digitalization of inefficient processes and technologies only leads to inefficient digital processes, including in NDT and CM.

Волны деформации в двух соосных, физически нелинейных оболочках с конструкционным демпфированием, взаимодействующих с окружающей средой и заполненных жидкостью

The paper investigates longitudinal strain waves in physically nonlinear coaxial elastic shells containing a viscous incompressible fluid situated both between the shells and within the inner shell. The study takes into account the effects that the following factors have upon the magnitude and velocity of the wave: viscosity, fluid motion inertia, the medium surrounding the outer shell, and structural damping in the shell material. As it is impossible to evaluate the strain wave models proposed via qualitative analysis methods, using numerical methods is necessary. We numerically investigated the model presented using a specific difference scheme to represent its equations, one similar to the Crank --- Nicolson scheme for the thermal conductivity equation. We show that the velocities and amplitudes of strain waves in the shells do not change when disregarding the following factors: the fluid inside the shell, structural damping in the shell material, and the influence of the surrounding elastic medium. The waves evolve in the positive direction of the abscissa axis. At the same time, taking nonlinearity into account leads to increased wave velocity as compared to the linear case, when the wave propagation velocity equals the speed of sound, which means the waves become supersonic. We performed a numerical study of this case and obtained results matching the exact solution. If we take into account the effect that the fluid motion inertia within the inner shell has upon the wave velocity, then a decrease in the strain wave velocity is observed. Taking into account the presence of an elastic medium surrounding the outer shell leads to an increase in velocity. Considering the viscous properties of the fluid within the inner shell and the damping properties of the shell material results in decreased strain wave magnitudes. The models proposed can form the basis for designing modern non-destructive testing devices

Validation of wireless impact echo prototype for condition assessment of concrete structures

A new wireless impact echo prototype was developed for the condition assessment of reinforced concrete slabs. The new system includes a wireless handheld sensing device which connects by Bluetooth to a tablet equipped with a user-friendly software for managing the testing grid, recording measurements, processing and transforming the data to a frequency domain, and presenting the results in real time. To validate the device, three large-scale concrete slabs of dimensions 2000 mm x 2000 mm x 300 mm were fabricated with artificial defects including voids, delamination, vertical cracks, and geometric discontinuities. The influence of slab boundaries, defect depth and location, overall thickness, steel reinforcement, and an internal conduit on the obtained measurements were investigated. The results were also compared with other commercial non-destructive testing devices including ground penetrating radar (GPR) and ultrasonic pulse velocity (UPE), and the advantages and disadvantages of each method are discussed. Overall, the results suggest that the impact echo technique using the new wireless prototype is able to accurately detect and characterise various defect types provided that the right size of impactor is used. Use of improper impactor sizes can result in alternative vibration modes depending on the slab thickness and defect depth; in that case, multiple readings may be required. The new system greatly improved the ease-of-use of the impact echo technique, although the inspector should be trained to properly interpret the results. Compared with the GPR technique, the impact echo system was not as rapid and unable to detect the location of steel reinforcement; on the other hand, it was better able to detect defects in the presence of steel bars which tended to obscure readings using GPR. UPE measurements were also faster than the impact echo tests and performed well for slab thickness measurements and detection of certain defect types; however, readings were found to be affected by the presence of steel reinforcement and in some cases were inconsistent. Overall, it may be concluded that each technique presents certain strengths and weaknesses that should be considered in the condition assessment strategy. The results obtained from each technique are complementary and may be used to develop a complete understanding of the internal state of the structure.

Determination of Dynamic Range of Stand-alone Shock Recorders

Abstract In aircraft construction, when creating samples of new equipment, shock tests are often performed, both on individual components and the entire product. It requires introducing non-destructive testing devices into production, it is one of the most important factors in accelerating scientific and technological progress, raising the quality and competitiveness of manufactured products. Applying modern means of non-destructive testing, there is the problem of their protection from external vibrations, which affect the sensitivity, accuracy and reliability of high-precision measurements. In such cases, the conversion of measuring information during powerful vibration and shock tests, as a rule, is carried out by piezoelectric acceleration sensors. Although to provide impact testing, there is a need to develop and use stand-alone recorders. The main requirements for these recorders are to ensure the autonomy and operability of the recorder onboard the test product and to ensure the synchronization of the registration of the shock load.