Ultrasonic Testing Method Research Articles

Автоматизация процесса контроля качества сварных соединений

The analysis of the electric arc welding process is performed. The main types and causes of defects in welded joints have been identified. The main non-destructive methods of control of welded joints are analyzed. The revealed advantages and disadvantages of each method. The method of ultrasonic testing is considered in sufficient detail. Shown on the practical experience of ultrasonic inspection of welded joints by a flaw detector with antenna arrays. The features of application of the program for PC «USD-soft», which allows automating the control of welded seams, are considered.

Ultrasonic Fatigue Device and Behavior of High-Temperature Superalloy Inconel 718 with Self-Heating Phenomenon

Ultrasonic resonance fatigue test method at 20 kHz related to the very high cycle fatigue (VHCF) aims to accelerate a time-consuming experiment. In this paper, an ultrasonic fatigue device with a data acquisition system was improved for monitoring and recording the data from fatigue tests in which self-heating phenomenon exists. Symmetric tension-compression sinusoidal vibrating mode (R = −1) was observed in this study. VHCF behavior and mechanism of Inconel 718 were carried out using this device. It was concluded that more than 99% of fatigue life is consumed in initiation duration. Specimen temperature increase was not a decisive factor in VHCF strength for Inconel 718, as long as it was far less than the design temperature limitation. A single initiation site existed at the subsurface facet or grain cluster, observed from scanning electron microscope (SEM) micrographs. Quasi-cleavage fracture in transgranular ductile mode emerged and then tended to trace grain boundaries in an intergranular manner by cleavage-dominated mixed mode.

Research on the application of phased array detection in Power transmission and transformation metal equipment

This paper analyzes and compares the characteristics of conventional nondestructive testing method and ultrasonic phased array testing method, and introduces several ultrasonic phased array testing methods of power grid equipment. Ultrasonic phased array technology is a high-efficiency, intuitive and reliable new nondestructive testing technology. It is of great significance to apply ultrasonic phased array technology to the nondestructive testing of power industry equipment and explore the adaptability of its testing technology to ensure the reliable operation of equipment and the security of power grid.

Acoustic Methods for Testing Gas Turbine Engine Blades

In this paper the application technology of the ultrasonic testing method in the process of the PS-90A aircraft engine manufacturing is considered. It is known that the development and implementation of monocrystalline turbine blades for aircraft gas turbine engines are aimed at ensuring the material effectiveness or increasing the blade service life in comparison with polycrystalline blades. It is achieved at the cost of the increased long-term material strength in the same temperature range. Based on the results of the process and metallographic studies analysis, it has been established that during the structure formation under the internal stress action, hot crystallization cracks with an opening from 3 to 8 μm or more and a length of 3 to 35 mm along the grain boundaries can appear. Grains formation in most blades happens with their subsequent exit to the lock end, a bridge. The formation of hot cracks most likely occurs at a large grain disorientation angle (more than 25°). Grain boundaries on blades with hot crystallization cracks are located, as a rule, on the bridge at the junction of the blade root with the blade shank (“bottleneck”) with orientation along the blade axis. The method of contact laser-ultrasonic flaw detection (CLUFD) was tested on blades in the region of bridges using both pilot samples and standard parts in order to solve an urgent production and technical problem, that is timely detection of hot crystallization cracks in rotating turbine engine blades at the manufacturing stage. The use of the phased antenna array technology (PAR) in combination with a portable X-32 flaw detector represents a new level of blade ultrasonic testing. The flaw detector operates in a wide frequency range, which allows solving a very large range of various ultrasonic testing problems. The advantages and possibilities of the PAR technology with the portable X-32 flaw detector can be considered on the example of the turbine blade lock testing. S-scan (sector-scan) makes it possible to interpret the received signals quickly and easily.

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.

Nondestructive Testing Method for Welding Quality in Key Parts of Ocean-going Ships

Tang, F.D. and Yu, Y.F., 2020. Nondestructive testing method for welding quality in key parts of oceangoing ships. In: Al-Tarawneh, O. and Megahed, A. (eds.), Recent Developments of Port, Marine, and Ocean Engineering. Journal of Coastal Research, Special Issue No. 110, pp. 91–94. Coconut Creek (Florida), ISSN 0749-0208.Welding technology is widely used in the manufacture and production of structural parts of ocean-going ships. The quality of welding is crucial to the safety of ocean-going ships. This paper attempts to study the NDT methods for welding quality in the key parts of ocean-going ships. To this end, it first summarizes several typical defects that are common in key parts of ocean-going ships, and selects the butt welds on the deck as the research objects. Then, the conventional ultrasonic testing (UT), phased array ultrasonic testing (PAUT), and radiographic testing (RT) were used to conduct the NDT testing on the test plates. Finally, a comparative analysis was conducted for the test results of these three methods. The research results show that like the UT and RT methods, the PAUT can detect all defects, and the qualitative results are consistent; except for incompletely fused defects, its other testing results are better than the UT and RT, verifying the feasibility of the PAUT. The research findings enrich the practical research results of the PAUT in ship welding quality inspection, and provide an effective reference for the promotion of this testing method in marine ship welding quality.

Insight into rock crack propagation from resistivity and ultrasonic wave variation

By using a combined real-time electrical resistivity measurement and ultrasonic wave testing method, the changes in the electrical resistivity and ultrasonic wave information during the crack initiation, propagation and coalescence process of saturated greensand stone under uniaxial loading were investigated, and a method to predict the location of the potential through cracks in the sandstone was proposed based on the anisotropic characteristics of the resistivity. The crack propagation characteristics of sandstone under different loading speeds were analysed from the macro and micro perspectives based on the change in the resistivity. The results showed that there exists a significant correlation between the resistivity change, crack propagation and rock coalescence. Corresponding to the crack initiation, propagation and coalescence processes, the change in resistivity experiences four stages: the stationary stage, descending stage, sudden drop stage and surging stage. The anisotropic change in the resistivity on different testing faces of the rock shows that the anisotropic characteristic contributes to the understanding of the location and orientation where the macro-cracks form in the rock. The increase in the loading rate promotes the local concentration and expansion of micro-cracks in the rock, which can be reflected by the change in the resistivity: the higher the loading rate is, the faster the resistivity descends. With the increase in the loading rate, the failure of the rock tends to be more violent with relatively fewer fractures.

Research on Ultrasonic TOFD Testing Method of Electron Beam Weld

With the development of aerospace technology, electron beam welding technology has become an important part of the welding field. More and more aircraft and spacecraft parts adopt electron beam welding technology. However, in the process of electron beam welding, due to the influence of the incident angle of the electron beam, the deviation of the weld bead and the electromagnetic field, it is easy to produce defects such as unfused and blowholes. Therefore, it is necessary to conduct a non-destructive testing study on the electron beam weld. Aiming at the characteristics and defects of electron beam welds, the TOFD inspection method of electron beam welds was developed, the basic principles of TOFD inspection were introduced in detail, the TOFD acoustic beam coverage was calculated, and the TOFD inspection of electron beam welds was carried out based on self-developed systems Experiment and analyze the experimental results. Experiments show that the ultrasonic TOFD detection method can quickly and accurately detect electron beam welds, which is an effective method for electron beam weld detection.

Multiphysics simulation of the resistance spot welding detection using electromagnetic ultrasonic transverse wave

Resistance spot welding (RSW) quality substantially influences the autobody’s mechanical properties and safety performance. Nondestructive testing (NDT) method is widely used to evaluate the quality of RSW, but the traditional ultrasonic testing method has high requirements for coupling conditions and flat surface of the weld part. The electromagnetic acoustic transducer (EMAT) is a novel NDT technology, which has advantages of noncontact, no coupling media, and low requirements for surface flatness of the workpiece. Therefore, the electromagnetic ultrasonic transverse wave (EUTW) is developed to realize the evaluation of RSW quality in this paper. Under the COMSOL platform, the finite element method (FEM) modeling is proposed by multiphysics simulation. The multiphysical fields include electromagnetic field, acoustic field, and solid mechanics. The generation mechanism and propagation rules of EUTW in various spot welds are studied by simulation analysis. The correctness of FEM modeling is validated by EUTW experiments; results show that the experimental waveforms of EUTW are consistent with the simulation waveforms. Finally, an evaluation method of the nugget size of RSW is proposed based on the simulation and experiments analysis of EUTW detection of RSW with different nugget diameter and indentation depth. The approach presented in this paper can provide the theoretical foundation and new method for the noncontact, high efficient, and low-cost detection of RSW quality of the autobody.

Study on the Effect of Focused Ultrasound Excitation on Image Resolution Based on Computer Technology

With the continuous development of modern science and technology, ultrasonic testing is applied in various fields, and plays an important role in the field of detection. Ultrasound imaging is mainly used in medicine to detect the health of internal organs and to defect fetal development in obstetrics and gynecology. In addition, ultrasonic wave is widely used in welding inspection in the mechanical industry, and the downhole ultrasonic imaging is used in tunnel engineering. With the development of ultrasonic testing technology, there are many kinds of ultrasonic testing methods at present. This paper mainly discusses the influence of focused Based on Computer Technologyultrasonic’s excitation on imaging resolution, and finds out the law to perfect the ultrasonic testing means and improve the final imaging resolution. Focused ultrasonic excitation, also known as ultrasonic phased array detection technology, is an emerging non-destructive testing technology that has been developed and popularized in recent years[1]. Discussing and studying the influence of focused ultrasonic excitation on imaging resolution is of great significance to optimize this new technology. In the development of ultrasonic imaging technology, it is the responsibility of every relevant researcher to constantly explore ways to optimize the technology.

Graphic Augmented Defect Recognition for Phased Array Ultrasonic Testing on Tubular TKY Joints

A graphic augmented defect recognition algorithm was developed for phased array ultrasonic testing (PAUT) on tubular TKY joints. Based on PAUT sector scan (S-scan), 2D maps of the scans are obtained in terms of signal intensity and locations using spatial clustering and segmentation. The transformed S-scan data was further mapped with weld geometrical model to discriminate defect indications from the signals due to weld boundaries. Geometrical features of the identified defect indications were extracted to estimate the size and depth of the defects. The algorithm was verified by experiments on a TKY artefact with purposely-made defects. It shows that our algorithm was able to identify and locate all the defects in the artefact. Compared with the results obtained manually using the standard ultrasonic testing method, the differences of our results in terms of the defect size and depth were within 2 mm. The algorithm, coded into a software tool, demonstrated that the defects in the tubular TKY welds can be detected automatically and visualized in an intuitive manner.

Efficient volumetric non-destructive testing methods for additively manufactured parts

This paper presents the evaluation of two promising non-destructive testing (NDT) methods for the inspection of additively manufactured (AM) parts: a resonant acoustics method (RAM) and a phased array ultrasonic testing (PAUT) method involving a full matrix capture (FMC) acquisition procedure and a total focused method (TFM) to post-process the data and reconstruct the images. The two methods were evaluated using the so-called star artefacts designed in the international standardisation joint group 59 of the ISO/TC261-ASTM/F42 dedicated to NDT for AM parts. These artefacts contain inner and outer features simulating typical AM flaws lying between 100 and 700 μm. The RAM enabled to sort the artefacts with flaws from the reference artefacts without flaw. However, RAM was unable to separate the artefacts according to the number of flaws they contained. The detection with PAUT depended on the shape, orientation and location of the flaws. The best results were obtained for the vertical cylinders, simulating AM cross-layer flaws. They could be detected up to 200 μm.

Integrated Application of GPR and Ultrasonic Testing in the Diagnostics of a Historical Floor.

The paper presents the results of integrated ground penetrating radar (GPR) and ultrasonic testing (UT) measurements conducted on a historical floor in St. Nicholas’ Church, Gdańsk, Poland. The described inspection was the first stage of the technical state assessment of the building. The aim of the study was the detection of underfloor air gaps, which were observed in a few trial pits. The condition of the ground under the floor was determined by localizing other inclusions such as rubble, human remains, brick walls and pipes. To identify the phenomenon of electromagnetic and ultrasonic wave propagation within the air gap, laboratory tests were conducted on physical models consisting of two concrete slabs stacked on top of each other and gradually moved apart to simulate a slot of varying thickness. The conducted research was supported by the numerical models of electromagnetic wave propagation. The obtained results showed that the integration of the GPR and UT methods provided an effective imaging of the floor and the area under it. Ultrasonic testing was proved to be a good technique for identifying air voids, while the GPR method allowed detecting concentrated anomalies and determining the degree of ground homogeneity under the floor.

Fatigue Crack Detection in AISI 304 Austenitic Stainless Steel Using Nonlinear and Linear Ultrasonic Testing Methods

Fatigue cracks are often underestimated by traditional linear ultrasonic techniques due to the poor direction as well as narrow gaps within the cracks. The nonlinear ultrasonic testing technique is a promising method that may be used to solve this problem. In this study, the effects of traditional C scan imaging in measuring fatigue cracks are analyzed by comparing their results with that of metallography. Then, the finite amplitude method of nonlinear ultrasonic testing is used to detect micro-damages, and the influences of excitation voltage on the nonlinear coefficient are investigated. The results indicated that the accuracy in C scan imaging becomes worse when the crack’s surface is not perpendicular to the incident wave or if the crack’s gap is very small. In contrast, relative nonlinear coefficients under an optimum voltage increase according to the degree of micro-damage, which was found to not be affected by the status of macro-cracks but was particularly sensitive to the accumulation of micro-damage. This study suggests that nonlinear ultrasonic techniques be implemented to achieve beneficial effects in testing fatigue damage.

USING OF TOFD TECHNOLOGY IN THE DEVELOPMENT OF SPC “ECHO +”

Since the creation of SPC «ECHO +», special attention has been paid to ultrasonic testing methods that provide visualization of defect images and measurement of their sizes. Due to its high sensitivity and high accuracy, diffraction methods in many cases make it possible to solve the problem of identifying, classifying, and determining the parameters of defects. A review of the capabilities of equipment and software developed by SPC «ECHO +» for the implementation of TOFD technology is presented.

MEASUREMENT THICKNESS OF PROTECTIVE-DECORATIVE COATINGS ON CONCRETE BASES

The factors affecting to the ultrasonic testing of the coating thickness on concrete are considered. The structure and design of the transducer used to solve this problem. Features of the organization of the measurement process are described. Options for creating reference samples for tuning and testing ultrasonic thickness gauges used to solve this problem. The results of measuring the thickness of the polyurethane coating on concrete obtained on the Bulat 3 device using a specialized transducer are presented. The characteristics of concrete, which necessitate the use of special protective and decorative materials (surface abrasion, insufficient density, low hydrophobicity, etc.), and the characteristics of organic polymer coatings (adhesion, elasticity, wear resistance, chemical resistance, and hardness), which depend significantly on dry film thickness (protective layer). It is indicated that in order for the coating to ensure the fulfillment of the declared parameters taking into account economic feasibility, it is necessary to fulfill the requirements for a given minimum coating thickness, and that the use of the ultrasonic testing method seems to be the optimal method for measuring the coating thickness. Factors affecting the measurement process (the ratio of acoustic impedances, reflection coefficient and its variation range for various types of concrete and the most common coatings) are also considered. It is indicated that, based on a number of experiments with different types of transducers (dual element, single element and single element with the delay line), the maximum sensitivity and measurement range are ensured by using a direct single element transducer with a delay line. The data on the choice of the operating frequency of the transducer is given, depending on the range of measured coating thicknesses. The design and construction of the transducer, the features of the construction of its elements and their influence on the transducer characteristics, the principle of measuring the coating thickness and its implementation on the Bulat 3 ultrasonic thickness gauge are described. The char-acteristics of the device that allowed it to be used for such measurements are indicated. Information is provided on various options for the implementation of reference samples of the coating, on the methodology for their testing and the measurement results.

Fully noncontact measurement of inner cracks in thick specimen with fiber-phased-array laser ultrasonic technique

To realize a fully noncontact ultrasonic testing method for inner cracks inspection in thick metal specimen, a phased array laser ultrasonic testing system with using a compact optic fiber array bundle and a laser interferometer is developed in this study. The focusing and steering of the shear wave and longitudinal wave generated with seven fiber-phased-array laser sources in thermoelastic regime is investigated by a numerical simulation and validated by the experiment. A non-contact measurement of the inner-surface cracks by both the angle-beam testing method and time-of-flight diffraction method with the fiber-phased-array laser ultrasonic technique have been studied.

Research on Scanning Path of Automatic Phased Array Ultrasonic Testing of Pipe Welds with Complex Geometry

The automatic phased array ultrasonic testing method has been developed for inspecting the pipe welds with complex geometry. Applying time of flight diffraction (TOFD) technique has two problems: one is the difficulty in recognition of head wave under complex structure; the other is the limited scanning space cannot provide the needed span for pitch-catch mode. To overcome these two problems, an array probe can be placed on the surface of base metal of the weld by the direct and double traverse techniques. In order to design the optimal scanning path for high probability of detection and inspection rate, the model of beam path on tilt steps was established to quantitatively analyze the effects of tilt steps on beam coverage and mode conversion. Experiments were conducted to validate the proposed rule of planning the optimal scanning path. All artificial defects in the mock-up block were detected on the scanning side of which exists the optimal scanning path. While for the scanning side without the optimal scanning path, a combination of scanning is needed to avoid missing inspection.

Impact Damage Evaluation in Composite Structures Based on Fusion of Results of Ultrasonic Testing and X-ray Computed Tomography.

Barely visible impact damage (BVID) is one of the most dangerous types of structural damage in composites, since in most practical cases the application of advanced non-destructive testing (NDT) methods is required to detect and identify it. Due to its character of propagation, there are minor signs of structural damage on a surface, while the internal damage can be broad and complex both in the point of view of fracture mechanisms and resulting geometry of damage. The most common NDT method applied e.g., in aircraft inspections is ultrasonic testing (UT), which enables effective damage detection and localization in various environments. However, the results of such inspections are usually misestimated with respect to the true damage extent, and the quantitative analysis is biased by an error. In order to determine the estimation error a comparative analysis was performed on NDT results obtained for artificially damaged carbon fiber-reinforced composite structures using two UT methods and X-ray computed tomography (CT). The latter method was considered here as the reference one, since it gives the best spatial resolution and estimation accuracy of internal damage among the available NDT methods. Fusing the NDT results for a set of pre-damaged composite structures with various energy values of impact and various types of impactor tips applied for introducing damage, the evaluation of estimation accuracy of UT was possible. The performed analysis allowed for evaluation of relations between UT and X-ray CT NDT results and for proposal of a correcting factor for UT results for BVID in the analyzed composite structures.

Physical perspective forward-inverse learning for ultrasonic sensing diagnosis in small diameter and thin-wall tube

The ultrasonic testing method is a well-known non-destructive testing technique which has been applied to the tube inspection for guarantying the quality of the production. However, there exist several challenges to detect the defects of tubes with small diameter and thin-wall due to the complex of multiple reflections and waveform conversion. Parameters selection of the transducer takes key role to enhance the detection sensitivity such as frequency, size, refraction angle, distance offset, and focal point distance. This selection is generally dependent on human experience as it is highly time-consuming and subjective. In this paper, a novel parameter selection method based on physical perspective linked forward-inverse intelligence strategy has been proposed for ultrasonic immersed testing method. The optimized parameters can be calculated automatically while both testing and calibration repeated experiments can be avoided. The proposed method is computationally affordable and yields a high accuracy objective performance. Both simulation and experiments have been conducted to verify the efficacy of the proposed method.