Nondestructive Testing Devices Research Articles

Ultrasonic pitch and catch technique for non-destructive testing of reinforced concrete slabs

This study aims at evaluating reinforced concrete (RC) bridge elements using ultrasonic pitch and catch (UPC) non-destructive testing (NDT) technique. A validation reinforced concrete slab with two embedded layers of rebars and artificial defects (voids, honeycombs, and debondings) was designed and tested. A commercial UPC NDT device (hereafter called “UPC device”), which is based on the ultrasonic shear-wave test method using dry-point-contact transmitting and receiving transducers in a “pitch-catch” configuration, was used to map internal defects of the validation RC slab. The recorded data from the UPC device was analyzed using a modified synthetic aperture focusing technique (SAFT). A software was developed to reconstruct 2-D images of the RC slab cross-sections using novel signal filtering and processing techniques. The results revealed that the 2-D image reconstructed from the developed software accurately exhibited locations and horizontal dimensions of the steel rebars, voids, and debondings. In addition, the developed software was capable to provide much higher resolution and sharper images of the anomalies inside the RC slab compared to the UPC device’s proprietary imaging software.

Development of on-line nondestructive testing device for welding cracks based on piezoelectric ceramic excitation

Perform real-time non-destructive testing of weld damage in various welded structures of steel to determine the degree of weld damage in order to make timely safety warnings to protect human life and property safety. In this paper, piezoelectric ceramics are arranged on both sides of the weld to find the best frequency of the excitation system. The sine signal of this frequency excites the piezoelectric ceramics on one side, and receives and analyzes the response signals of the piezoelectric ceramics on the other side. This paper uses direct digital frequency synthesis technology (DDS), power management circuit, differential amplifier circuit, band-pass filter circuit, phase detection circuit, amplitude detection circuit, etc. to design a system that can perform real-time nondestructive testing. The whole system can measure the changes of these signals in real time, and send the signals to the upper computer remotely. Analysis of these signals can initially determine the size and location of weld damage. The research results show that when the weld in the steel is damaged, the amplitude of the sinusoidal signal propagating through the weld will be attenuated, and the phase difference between the transmitted signal and the received signal will increase. This change is positively correlated with the degree of damage.

Спеціалізовані пристрої неруйнівного контролю для оцінки технічного стану обертових та необертових частин механізмів

Спеціалізовані пристрої неруйнівного контролю для оцінки технічного стану обертових та необертових частин механізмів

Devices for non-destructive testing of building structures

This article has a goal - to give information about the conducted researches with the use of modern devices and instruments. Descriptions of автомaтизиpовaнной измepитeльной cиcтeмы are given for измepeния paзличных of types of дeфоpмaций иcпытывaeмых конcтpукций путeм peгиcтpaции and пpeобpaзовaния in инжeнepныe eдиницы in peaльном мacштaбe вpeмeни cигнaлов. Determination of defects and deformations in a transport building, condition of work.

Evaluation of flexible pavement deterioration conditions using deflection profiles under moving loads

With the development and application of highway-speed nondestructive testing (NDT) devices, a reliable method to evaluate the current level of deterioration of pavements from the measured results is necessary to provide comprehensive and timely maintenance and rehabilitation decisions for pavements. The objective of this study is to evaluate the deterioration conditions of flexible pavements from their deflection profiles under the moving loads. The deterioration is due primarily to the development and growth of microcracks in flexible pavement materials and is commonly called the “crack initiation” phase. This phase is characterized and represented by the decrease of the dynamic modulus and the increase of the phase angle. To simulate a flexible pavement under the moving loads, a three-dimensional (3D) finite element (FE) model is constructed using a commercial FE software and an equivalent two-dimensional (2D) axisymmetric FE model is built using the artificial intelligence (AI)-based FE model updating. The deflection profiles of the pavement model are analyzed and the time lag between the load and deflection peaks is used to define a new term named “lag angle” to represent the structural response of the flexible pavement under the moving loads. It is also found the lag angle is closely related to the degree of deterioration of the pavement, the speed of the moving load, the structural and material properties of the pavement, which reveals a promising application of the lag angle in the evaluation of flexible pavements using highway-speed NDT devices.

Electromagnetic acoustic transducers for non-destructive testing of main pipelines

The article presents the design options for high-performance electromagnetic-acoustic transducers for monitoring pipelines by the waveguide ultrasonic method. Methods for creating large polarizing fields, which make it possible to increase the efficiency of excitation and reception of Lamb and Rayleigh waves in ferromagnets are proposed. The results obtained in this paper can be used in the development of devices for non-destructive testing of trunk pipelines.

Research on Error and Compensation of Volume Measurement System for Nondestructive Testing

In order to improve the measurement accuracy of the three-dimensional non-destructive testing device for slice volume, the experimental error caused by the hydraulic loss of the experimental container is analyzed and compensated. Through the analysis of the overflow characteristics, the weir flow model of the overflow is established, the profile curve of the overflow and the overflow round tube are optimized to reduce local losses, and verified by experiment. The results show that the measurement accuracy of the liquid volume is improved by about 54.85%, and this optimization scheme is effective. By optimizing the experimental device, the error is compensated to ensure the accuracy of data collection.

Prediction of asphalt pavement condition using FWD deflection basin parameters and artificial neural networks

Applications of non-destructive testing devices such as Falling Weight Deflectometer (FWD) provide crucial estimates of pavement health that assist in the optimisation of pavement management systems. However, regularly conducting these tests at a network level and post-processing of the collected data is cumbersome, which requires technical expertise, significant time, funds, and other resources. Due to this structural aspect of pavements during the selection of maintenance or repair, decisions are often ignored. This study attempts to develop reliable correlations for estimates of two different deflection basin parameters using a number of structural, functional, environmental, and subgrade soil attributes as input. The data has been obtained through field tests over a 124 km long pavement network. Different artificial neural network-based models are trained by varying the number of hidden layers and neurons in these layers, for the above-mentioned purpose. The coefficient of determination and mean square error is decisive for the selection of best network architecture. These outcomes are also compared to the results of the classical multiple linear regression method, and the superiority of neural networks over non-intelligent approaches for non-linear problems of pavement engineering is appreciated. In addition to this, the results justify the fact that the properties of the asphalt layer predominantly impact the entire pavement condition. The proposed approach is an alternative way to facilitate quick pavement condition assessment by reducing the frequency of deflection testing without compromising with the accuracy of its estimates. It would encourage the increased application of structural condition data in pavement maintenance and rehabilitation necessities with ease. However, the study does not intend to completely avoid conducting deflection testing and serve as a base for future studies.

A Manually Reconfigurable Reflective Spatial Sound Modulator for Ultrasonic Waves in Air

AbstractPrecise control of ultrasonic acoustic waves with frequencies f ≳ 20 kHz is useful in a range of applications from ultrasonic scanners to nondestructive testing and consumer haptic devices. A spatial sound modulator (SSM) is the acoustic analogy to the spatial light modulator (SLM) in optics and is highly sought after by acoustics researchers. A spatial sound modulator is constrained by very distinct practical conditions. Namely, it must be a reconfigurable device which modulates sound arbitrarily from a decoupled source. Here a reflective phase modulating device is realized, whose local units can be tuned to imprint a phase signature to an incoming wave. It is manually reconfigurable and consists of 1024 rigidly ended square waveguides with sliding bottom surfaces to provide variable phase delays. Experiments demonstrate the ability of this device to focus ultrasonic waves in air at different points in space, generate accurate pressure landscapes, and perform multiplane holography. Moreover, thanks to the subwavelength nature of the unit cells, this device outperforms state‐of‐the‐art phased‐array transducers of the same size in the quality and energy distribution of generated acoustic holographic images. These results pave the way for the construction of electronically controlled reflective SSMs.

Determination of the Place Depressurization of Underground Pipelines in the Monitoring of Oil and Gas Enterprises

Analytical correlations of mathematical model that characterizes the processes of development of corrosive cavity on the surface of underground metallic pipeline are analysed. A pipeline in the environment of moist soil with solution of electrolyte is placed.In the top of cavity a crack appears and translates the system “underground pipeline (UP) – pumping station (PS)” in the state of depressurization.A new approach is proposed for diagnosing places of underground pipeline depressurization on the basis of two types of devices: pressure sensors and non-destructive testing devices, with the help of which we measure potentials and corrosion currents in surface defects.The presence of only pressure sensors makes it possible to set the coordinates of depressurization with a large error – 20…25%. Diagnosis of the pipeline only by devices BVS-K, VPP-M (at the first stage) allows to reveal surface defects. But this information is not enough for a qualitative experiment, as shown by the qualimetric quality criterion. Taking into account the pressure data in the second stage allows to determine which of the defects is the leakage point.A test example for the distance L1 = 6 km from the pumping station of the pipeline is considered. The results of the experiment are used for the example and the growth time of the corrosion crack t = 0.62 year is established.On the basis of computational experiment the errors of estimating of crack growth time t and coordinates of the leakage points was established. They present 5…7 %. Based on the method of neural networks, the main informative parameters for determining the places of depressurization on the surface of the underground pipe are estimated. A method for estimating the gas pressure change in the vicinity of the crack after depressurization of the pipeline was proposed. The principles of determining the limit values of the parameters of the system “pipeline – pumping station” taking into account the criteria of quality and strength of the metal are formulated.

Development of a high resolution x-ray inspection system using a carbon nanotube based miniature x-ray tube.

A new concept for a non-destructive testing device using a novel carbon nanotube (CNT) based miniature x-ray tube is proposed. The device can be used for small-scale internal inspection of objects. To investigate the effectiveness of the proposed concept, the device was fabricated and its performance was systematically analyzed. The non-destructive testing device consists of a CNT based miniature x-ray tube, a scintillator, an optical lens, and a detector. The size of the focal spot needed to identify objects as small as 5 µm was calculated through simulation. An electron optics simulation software, E-GUN, was used to optimize the geometries of both the focusing cup and the x-ray target to achieve the desired focal spot size of the x-ray tube. The CNT based miniature x-ray tube was fabricated using the brazing process, and an NdFeB focusing lens was used to further reduce the focal spot size. XR images were obtained using the fabricated device and the spatial resolutions of the images were evaluated using the modulation transfer function (MTF). The fields of view (FOVs) per probe are 7.1 mm2 and 1.8 mm2 when using a 5× optical lens and a 10× optical lens, respectively. The FOV can be increased by increasing the number of probes incorporated into the device. MTF10 values were determined to be 105 lp/mm and 230 lp/mm when using the 5× optical lens and 10× optical lens, respectively. By using an optical lens to enlarge the XR images, the effect of focal spot was minimized and clear XR images were obtained.

Застосування спеціалізованого пристрою неруйнівного контролю для аналізу вібраційних сигналів підшипникових вузлів методами взаємного нестаціонарного аналізу

Застосування спеціалізованого пристрою неруйнівного контролю для аналізу вібраційних сигналів підшипникових вузлів методами взаємного нестаціонарного аналізу

Measuring the Strength of Concrete in the Underwater Part of Hydraulic Structures

Devices for nondestructive testing of concrete strength (separation with chipping, ultrasound, elastic rebound method) allow to measure the strength only in the air. But for inspecting hydraulic structures (for example, piles of berths), it is necessary to measure the strength of concrete under water. For this purpose, it is possible to use the method of plastic deformation using a shotgun as a percussion device for spearfishing while providing a constant (controlled) force of impact. The works described in the article on obtaining special calibration dependences allowed to successfully apply the method of plastic deformation for measuring the strength of concrete in the inspection of piles of berths in the Black, Barents and Okhotsk seas

Timber moisture content adjustment factors for nondestructive testing (NDT): acoustic, vibration and probing techniques

Abstract Nondestructive testing (NDT) includes several highly efficient techniques for the estimation of the physical and mechanical properties of structural timber. However, NDT results are affected by several factors [moisture content (MC), temperature, specimen dimensions, sensor positioning and grain angle, timber-sensor coupling, etc.], of which wood MC is the most important. Scientific research on MC influence in NDT measurements started in the 19th century, and 2018 was the first year that a MC adjustment for NDT measurements was published in a European standard (EN14081-2). Although MC influence on NDT has been studied for more than 170 years, MC adjustment factor research is important nowadays because it is widely used in the industry. Currently, NDT device manufacturers develop their own MC adjustment factors adapted to their equipment and species. This paper presents an exhaustive review of MC adjustments for different types of NDT equipment, as proposed by several authors from the 19th century to date, and a discussion of factors affecting MC adjustments.

3-D BEM Formulations for Eddy-Current Problems With Multiply-Connected Domains and Circuit Coupling

Quasi-static linear problems can be solved efficiently with Boundary Element Method (BEM). This method is based on surface integral equations dealing with equivalent magnetic and electric surface current densities. Many works have shown the potentiality of BEM especially for the modeling of non-destructive testing devices. In this paper, after selecting formulations enabling the modeling of multiply-connected regions, an original coupling is proposed in order to take into account external electric circuit in the problem.

Nondestructive testing of turbine disk roots using solid-state GMR sensor arrays and an axial directional scanning system

A nondestructive testing device, consisting of a scanner and signal processing circuits was developed to detect cracks in turbine disk roots. The scanner consists of a longitudinal feeder and a fir-tree-shaped sensor probe. The feeder inserted the sensor probe along the grooves of the turbine blade attachment. Meanwhile, permanent magnets were placed in opposite direction, to generate a closed magnetic field between the magnetic sensors located on the crests of the sensor probe. The fatigue crack in the turbine disk root occurred in the circumferential direction of the turbine. As a result, magnetic flux leakage was caused by disturbing the flow of closed magnetic field by permanent magnets. The magnetic flux leakage was measured by a magnetic sensor. The effectiveness of the proposed device has been verified using artificial defects introduced into the turbine disk roots by electric discharge machining.

A miniaturised active thermography system for in-situ inspections

With the increase of the functionalisation, integration and complexity of industrial components and systems, deploying Non-Destructive Testing (NDT) devices for ‘in-situ’ inspection has become a major challenge for high-value assets. Due to the mismatching of size and volume between the existing inspection unit and the targeted complex object, inaccessibility and inapplicability have limited the applicability of NDT techniques. To address this challenge, this paper introduces a novel miniaturised active thermography system based on a commercial thermal imaging sensor featured with small size and low cost. Combining with different excitation sources, its detection performance on different types of defect of carbon fibre reinforced polymer (CFRP) is investigated and compared with an existing system. The results show that the proposed system can work with laser and flash effectively for degradation assessment although the detectability is compromised. Such a technique will play a unique role in the in-situ inspection where the space to deploy the device is limited.

О возможности применения бета-альбедно-абсорбционного метода для создания приборов неразрушающего контроля размерных параметров наноматериалов (толщины, поверхностной плотности и покрытий) при их производстве

The explanation is given of the feasibility of using of a relatively unknown beta-albedo-absorption (BAA) technique, which was the research topic of the PHD thesis of the author, for the creation of a modern, unparalleled anywhere in the world, non-destructive testing (NDT) system to be used for the production of nanomaterials with main dimension parameters (thickness, surface density, and coating) in the nanorange, i.e., practically from zero to several hundreds of nanometers. The importance of the problem is determined by the present time intense development both in Russia and all over the world of the production of nanomaterials of different types in the practical absence of the development and production of NDT devices. Analytical expressions are given for the calculation of the main quantitative characteristics of BAA measurement geometry, namely, the radial density distribution and the integral electron backscattering coefficient at the variables of the parameters of the reflecting gas or air medium. The principle of developing the optimum measurement geometry, little dependent on changing parameters of the reflecting medium and minimizing measurement errors for BAA method, is described. The design of the developed detectors is shown. The following recommendations are given on additional experimental studies of the BAA method aiming to provide a possibility of parameter measurement in the nanorange: using the industrial beta sources with a lower value of the maximum beta spectrum energy; increasing the activity of beta sources or measurement time; using special filters for degradation of the beta source emission spectrum; and using beta radiation detectors with the largest possible measurement area.

Ultrasonic nodal chains in topological granular metamaterials

Three-dimensional (3D) Weyl and Dirac semimetals garner considerable attention in condensed matter physics due to the exploration of entirely new topological phases and related unconventional surface states. Nodal line and ring semimetals, on the other hand, can facilitate 3D band crossings characterized by nontrivial links such as coupled chains and knots that are protected by the underlying crystal symmetry. Experimental complexities and detrimental effects of the spin-orbit interaction, among others, pose great challenges for the advancement that can be overcome with other systems such as bosonic lattices. Here we demonstrate that a 3D mechanical metamaterial made of granular beads hosts multiple intersecting nodal rings in the ultrasonic regime. By unveiling these yet unseen classical topological phases, we discuss the resilience of the associated novel surface states that appear entirely unaffected to the type of crystal termination, making them a promising platform in ultrasonic devices for non-destructive testing and material characterization.

Ultrasonic testing system design for defect visualization of inhomogeneous multi-layered pipes

One of the major concerns of pipe equipment used for oil, gas and nuclear power generation, is their failure due to corrosion and abrasion of their inner walls. However, current methods have some problems detecting the inner wall of long and deep pipes, which has become an urgent safety problem. In this paper, we have designed and tested a suitable scanning and imaging method that offers high quality imaging, high efficiency and low cost. We applied the technique on remanufactured ceramic-lined steel composite pipe parts using a 4-module visualization nondestructive testing device. Digital signal and imaging algorithms were employed to superimpose multi-interface images to reconstruct 3D models of tested pipes with defects. Our findings suggest that ultrasonic scanning technique is feasible to analyze inner wall damages. The newly-designed hardware and software system shows efficiency and effectivity in the testing experiments on specimens with artificial markers and defects.