Non-destructive Ultrasonic Technique Research Articles

Crack detection using serrated columnar phased array transducers

This paper presents an ultrasonic non-destructive technique for detecting cracks on the outside surface of hollow shafts, specifically on the hollow axles used in high-speed railway trains. Traditionally, the cracks on the outside surface of hollow shafts have been detected from the inside of the central bore with monocrystal or phased array (PA) ultrasonic transducers. However, this approach still requires wedges and mechanical rotation to scan the entire cross-section while moving along the axial direction. This paper studies the performance of a serrated columnar phased array ultrasonic transducer (SCPAUT) in the detection of longitudinal cracks on the outside surface of a hollow axle specimen. By rotating each rectangular element of a columnar phased array with a proper angle, the SCPAUT was designed to transmit shear waves through the curved inner interface and rotationally scan the outside surface with electrical control. A prototype SCPAUT probe was made and evaluated on a cut hollow specimen with a certain number of artificial longitudinal cracks on the outside surface. The depths of the cracks ranged from 1 mm to 5 mm and numerous cracks were manufactured with a certain inclined angle relative to the normal direction of the outside surface. The finite element method (FEM) technique was used to study the ultrasonic wave propagation and the results were compared to those from a dynamic photoelastic experiment. The results demonstrated that the wave beam transmitted from the SCPAUT could be rotated axially and focused on the outside surface by using electrical control. The artificial longitudinal cracks were detected in the experimental test and the results of B-scan imaging of the cracks were presented.

In-situ formation of Al2O3/Al core-shell from waste material: Production of porous composite improved by graphene

Aluminum dross produced from aluminum industry was used to fabricate Al2O3/Al porous composites. The dross was milled for 20 h to obtain nano powder. The milled material was examined by TEM and XRD. Graphene (up to 4 wt%) was mixed with the dross and utilized to reinforce sintered composites. The milled powders were compacted then fired at various temperatures up to 700 °C. Physical properties in terms of bulk density and apparent porosity for sintered composites were tested using Archimedes method. SEM attached by energy dispersive spectrometer (EDS) was used to inspect microstructure and elemental analysis of sintered composites. Microhardness and compressive strength were also measured. Ultrasonic nondestructive technique was utilized to examine the elastic moduli. Electrical conductivity of sintered composite was also studied. During milling up to 20 h, Al2O3/Al core-shell was in-situ formed with size of 65.9 and 23.8 nm, respectively. The apparent porosity of sintered composites was improved with rising graphene percent while it decreased with increasing sintering temperature. Increasing of graphene mass percent and firing temperature led to remarkable increase in all mechanical properties and electrical conductivity. The maximum compressive strength, hardness, elastic modulus and electrical conductivity were 200 MPa, 1200 MPa, 215 GPa and 1.42 × 10−5 S/m, respectively, obtained for composite sintered at 700 °C having 4 wt% graphene.

Cloud Manufacturing On-demand Services for Holistic Quality Assurance of Manufactured Components

A cloud manufacturing architecture is proposed to offer on-demand services for holistic quality assurance of manufactured components with the aim to detect different kinds of features and potential defects related to the component external geometry and internal material structure. At the physical level to be connected to the cloud service, two non-contact testing procedures are employed: a laser-based reverse engineering method and an ultrasonic non-destructive inspection technique. The cloud server receives the pre-processed data and provides integrated information offering 3D visualization and manipulation of the heterogeneous data into a single interactive user interface to obtain a holistic evaluation of the manufactured component.

Full-volume Ultrasonic Technique for 3D Thickness Reconstruction of CFRP Aeronautical Components

Nowadays, carbon fibre reinforced polymers (CFRP) are widely utilized for the construction of light weight aircrafts. The main technologies for assembly and joining composite aircraft structures are drilling and bonding. Failures of bonded joints or bolted attachments can occur within the composite structure; therefore, each manufactured composite structure needs to be accurately inspected. In this paper, an advanced ultrasonic non-destructive evaluation technique based on full volume ultrasonic scanning is applied for the characterization and the 3D thickness reconstruction of two diverse CFRP aeronautical components to obtain a quality assessment of the process and a 3D representation of the defects.

Ultrasensitive plano-concave optical microresonators for ultrasound sensing

Highly sensitive broadband ultrasound detectors are needed to expand the capabilities of biomedical ultrasound, photoacoustic imaging and industrial ultrasonic non-destructive testing techniques. Here, a generic optical ultrasound sensing concept based on a novel plano-concave polymer microresonator is described. This achieves strong optical confinement (Q-factors > 105) resulting in very high sensitivity with excellent broadband acoustic frequency response and wide directivity. The concept is highly scalable in terms of bandwidth and sensitivity. To illustrate this, a family of microresonator sensors with broadband acoustic responses up to 40 MHz and noise-equivalent pressures as low as 1.6 mPa per √Hz have been fabricated and comprehensively characterized in terms of their acoustic performance. In addition, their practical application to high-resolution photoacoustic and ultrasound imaging is demonstrated. The favourable acoustic performance and design flexibility of the technology offers new opportunities to advance biomedical and industrial ultrasound-based techniques.

Effect of sintering temperatures on the in vitro bioactivity, molecular structure and mechanical properties of titanium/carbonated hydroxyapatite nanobiocomposites

Titanium-containing carbonated hydroxyapatite (Ti-CHA) nanocomposite powders, with different CHA contents, have been prepared using high-energy ball milling method. The effect of sintering temperatures, 900, 1100 and 1300 °C on molecular structure and microstructure of these samples were examined by XRD; Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM), respectively. Furthermore, their mechanical properties including hardness, longitudinal modulus, Young's modulus, shear modulus, bulk modulus and Poisson's ratio were measured by ultrasonic non-destructive technique. Moreover, bioactivity of sintered samples at different firing temperatures was assessed by immersing them in simulated body fluid at 37 ± 0.5 °C for 7 days and then, analyzed by FTIR spectroscopy. The results pointed out that increasing sintering temperature up to 1100 °C caused significant increases in densities and mechanical properties of these nanocomposite samples. However, further increase of firing temperature to 1300 °C was responsible for complete CHA decomposition and the resultant α-tricalcium (α-TCP) phase greatly affected these properties. On the contrary, better bioactivity was observed for sintered samples at 900 °C only. However, increase of sintering temperature of these samples up to 1300 °C led to severe decrease in their bioactivity due to the formation of highly soluble α-TCP phase.

超音波による非破壊検査技術( 音響センシングが拡げる測定技術の世界: 超低周波から超音波領域まで)

超音波による非破壊検査技術( 音響センシングが拡げる測定技術の世界: 超低周波から超音波領域まで)

СПОСОБЫ ОПРЕДЕЛЕНИЯ ОБЪЕМНОЙ ДОЛИ ПОР В ПОЛИМЕРНЫХ КОМПОЗИЦИОННЫХ МАТЕРИАЛАХ С ПОМОЩЬЮ УЛЬТРАЗВУКОВЫХ МЕТОДОВ НЕРАЗРУШАЮЩЕГО КОНТРОЛЯ (обзор)

СПОСОБЫ ОПРЕДЕЛЕНИЯ ОБЪЕМНОЙ ДОЛИ ПОР В ПОЛИМЕРНЫХ КОМПОЗИЦИОННЫХ МАТЕРИАЛАХ С ПОМОЩЬЮ УЛЬТРАЗВУКОВЫХ МЕТОДОВ НЕРАЗРУШАЮЩЕГО КОНТРОЛЯ (обзор)

Testing by Non-Destructive Control

This paper describes an application of industrial robots that gain ground mainly in the aerospace industry. It is a TTT manipulator whose task is to automatically position the end-effector, in this case a complex sensor system and a eddy-current probe in the position set by the software application for testing by non-destructive ultrasound control of tickets and bars of titanium, both round and square, or any other transparent ultrasound metal (obviously in a certain range of sizes). For surface control, the effector also includes a Eddy current (Eddy current control system). The installation performs ultrasonic control by the echo boost method in total immersion using as a water coupling medium. This method provides the best coupling for automated control systems. This plant was specially produced for ZIROM S.A. A unique producer of titanium ingots in Romania by the reputed German company Karl Deutch (leader in this field), the founder of the company being also one of the inventors of the non-destructive ultrasonic control method, the part of Eddy current being produced by the German company Pruftechnik. This paper aims to explore the state of the art of non-destructive automatic ultrasonic control techniques according to the possible methods to be adopted, by the applications that demand such methods, by reviewing a series of installations more or less similar to those of Zirom s.a. It is thus found that there are a multitude of pine technical solutions that can be done with an ultrasonic automatic control and precision. In this context, the last chapter of the paper that attempts to probe the possible evolution of the future of US control in this field is of great importance because in the current pace of innovations in all fields, but especially in IT and electronics, the future holds many surprises.

Определение формы объекта в ультразвуковой дефектоскопии с помощью кусочно-линейного представления

A new way of representing the shape of an object bottom using non-destructive ultrasonic testing techniques is proposed. The image of the examined object’s bottom is represented by a set of short segments. Each of these segments is a tentative ultrasonic signal reflection place. The segment intersection place is the place at which the ultrasonic signal is reflected. An algorithm for erasing segments that are not a place at which the ultrasonic signal is reflected from the bottom is proposed. This erasing is performed using elementary logic and takes a short time to do. The segments that remain after erasing are the places at which the ultrasonic signal is reflected from the bottom. Since the medium is constant and remains unchanged, it becomes possible to accumulate the obtained echo signals. Owing to this feature, the synthetic aperture method is used. An ultrasonic pitch-catch sensor moving with a constant step is used. Each signal is saved in memory. The total number of steps is N. After obtaining the echo oscillograms, the signals are subjected to processing. It is assumed that strong attenuation of ultrasound is observed in the object being examined, due to which a complex modulated signal is used. Computer-aided simulation was carried out. A new shape of the object bottom is used in each computer model. The proposed method for visualizing the object’s bottom shape is compared with a tomogram. A homogeneous medium with strong damping is used in the computer model. Experiments with a new object bottom shape in each of them are carried out. The tomogram and the proposed method for visualizing the object bottom shape are compared with each other. Water was used in the experiment as the medium. The obtained results have been compared with each other, and conclusions have been drawn. In many cases, the new representation of an object gives a clearer picture.

Acoustoelasticity in cancellous bone.

Strain-dependence of ultrasound speed in cancellous bone was determined by applying a range of uniaxial compressive strains in the elasticity region, in a single direction, parallel or perpendicular to the propagating wave. Compressive strain modulated the ultrasound speed significantly. The decrease of ultrasound speed was found to change linearly as a function of strain. The changes of broadband ultrasound attenuation were also determined for the two dilatational waves (parallel or perpendicular to the strain). They do not follow linear relation or constant sign of change with strain for the examined specimens. Considerable possibilities open up for using developments in acoustoelasticity for nondestructive ultrasonic techniques.

Prediction of elastic and acoustic behaviors of calcarenite used for construction of historical monuments of Rabat, Morocco

Natural materials (e.g. rocks and soils) are porous media, whose microstructures present a wide diversity. They generally consist of a heterogeneous solid phase and a porous phase which may be fully or partially saturated with one or more fluids. The prediction of elastic and acoustic properties of porous materials is very important in many fields, such as physics of rocks, reservoir geophysics, civil engineering, construction field and study of the behavior of historical monuments. The aim of this work is to predict the elastic and acoustic behaviors of isotropic porous materials of a solid matrix containing dry, saturated and partially saturated spherical pores. For this, a homogenization technique based on the Mori–Tanaka model is presented to connect the elastic and acoustic properties to porosity and degree of water saturation. Non-destructive ultrasonic technique is used to determine the elastic properties from measurements of P-wave velocities. The results obtained show the influence of porosity and degree of water saturation on the effective properties. The various predictions of Mori–Tanaka model are then compared with experimental results for the elastic and acoustic properties of calcarenite.

Low velocity impact response of composites and fiber metal laminates with open holes

Low-velocity impact response of glass/epoxy composite plates and fiber metal laminates with and without holes is investigated. The critical parameters that affect the delamination characteristics of laminates are impact energy, holes separation distance, type and directionality of fibers. An experimental investigation has been conducted to evaluate the effect of the presence of holes and the incorporation of aluminum layers in the extent of delamination. The extent of damage introduced during the impact event was observed on images obtained from C-scan non-destructive ultrasonic technique. Results indicate that fiber metal laminate made with aluminum layers exhibits an improved dynamic response in comparison with that of conventional laminates. The beneficial effect of using aluminum layers to reduce the extent of delamination produced by impact loading especially on laminates with holes is demonstrated. Furthermore, fiber metal laminates show better load carrying capability than conventional composite plates. The better response of fiber metal laminate with multidirectional fabric in comparison with fiber metal laminate with woven fabric is also examined. These results may be useful to better design the location of holes in composite structures.

Evaluation of Textural and Structural Properties of Barbari Bread During Storage

This study was performed using three Barbari flours (strong, medium, and weak) with different physical, chemical, and rheological properties. Determination of texture firmness of Barbari breads (A, B, and C, made of strong, medium, and weak flours, respectively) during storage was carried out with a texture analyzer and evaluating the bread crumb properties and changes during storage with a nondestructive ultrasonic technique. The bread microstructure was assessed with scanning electron microscopy, and the general process of starch gelatinization and retrogradation was evaluated with differential scanning calorimetry. The bread sensory properties were evaluated by 10 trained panelists. Barbari A, made from strong flour, had less firmness, lower transition of ultrasonic wave velocity, lower value of elastic modulus, reduced value of enthalpy, lower average temperature, larger pore diameter and area of images, and higher point total in sensory evaluation than Barbari B and Barbari C, particularly the latter, as storage time progressed. Barbari A's desirable quality characterization and longer shelf life were owing to the qualities of the flour, which enabled the production of dough with the appropriate properties. Eventually, the results of device‐based and sensory tests were significantly correlated. Ultrasonic nondestructive testing is recommended over other methods for assessing the texture, cell structure, and elastic properties of bread after baking and during storage, because it is fast, nondestructive, and less expensive than other methods and can be used during production.

Propagation of Ultrasonic Guided Waves in Composite Multi-Wire Ropes.

Multi-wire ropes are widely used as load-carrying constructional elements in bridges, cranes, elevators, etc. Structural integrity of such ropes can be inspected by using non-destructive ultrasonic techniques. The objective of this work was to investigate propagation of ultrasonic guided waves (UGW) along composite multi-wire ropes in the cases of various types of acoustic contacts between neighboring wires and the plastic core. The modes of UGW propagating along the multi-wire ropes were identified using modelling, the dispersion curves were calculated using analytical and semi-analytical finite element (SAFE) techniques. In order to investigate the effects of UGW propagation, the two types of the acoustic contact between neighboring wires were simulated using the 3D finite element method (FE) as well. The key question of investigation was estimation of the actual boundary conditions between neighboring wires (solid or slip) and the real depth of penetration of UGW into the overall cross-section of the rope. Therefore, in order to verify the results of FE modelling, the guided wave penetration into strands of multi-wire rope was investigated experimentally. The performed modelling and experimental investigation enabled us to select optimal parameters of UGW to be used for non-destructive testing.

Effect of steamside oxidation and fireside corrosion degradation processes on creep life of service exposed boiler tubes

In conventional steam plants, the efficiency mainly depends on the outlet steam temperature of boiler. The outlet steam temperature is maintained by subjecting different sections of boiler to high temperatures. In these harsh conditions boiler tubes undergo different degradation processes viz creep, fatigue, steamside oxidation, fireside corrosion and erosion. Therefore, life evaluation of boiler components is required at regular intervals of time for better functionality of power plant. Various life assessment techniques like microstructural evaluation, hardness measurements, Oxide scale measurements, Accelerated temperature tests are used for assessing the residual life of boiler tubes. In this paper, the creep life is estimated using destructive accelerated temperature tests on several T22 tubes from various sections of Platen Superheater, Final Superheater and Reheater of boiler. Accelerated temperature tests are carried out at higher temperatures under the nominal steam load and remaining life is estimated by extrapolating the results for the constant service temperature. But, the service temperature of tube never remains constant during a regular plant operation due to insulation effect of steamside oxidation and fireside corrosion. Further, during start up and shut down of plant, tubes undergo low cycle fatigue damage. Though, the life consumption of boiler tube due to fatigue is infinitesimal compared to creep because of thinner section of tubes. Therefore, the effect of cyclic operation is not considered, but the effect of steamside oxidation, fireside corrosion and erosion are incorporated in the accelerated temperature test results in estimating the residual life of boiler tubes. Further, these results are compared with the life obtained from Oxide scale thickness measurements carried out by Non-destructive Ultrasonic technique. In both the methods, metal temperature calculation using steady state conductive heat transfer equations play a crucial role in estimating the residual life. Mainly, these methods are based on thermal properties of oxide scale and short term stress rupture tests. Therefore, these methods can be applied for different grades of boiler materials such as T23, T24, T91 and T92 etc for residual life estimation.

Noncontact Ultrasonic Nondestructive Techniques: State of the Art and Their Use in Civil Engineering

AbstractUltrasonic noncontact methods of testing civil engineering materials in air, where both transmission of waves into materials and reception of signals are contactless, are reviewed. A short history and technical details of noncontact methods related to generation, reception, and transmission of waves are presented. Particular attention is devoted to enhancement of the signal-to-noise ratio by using coded signals. Next, examples of currently available solutions dedicated to (1) estimation of bulk properties of materials, (2) evaluation of state of concrete cover, (3) flaw detection, and (4) identification of structural parameters of porous materials are discussed. Applications of laser techniques, classical echo, direct through transmission, and different types of semicontact methods are topics that are not reviewed in this paper. Finally, the benefits and limitations as well as expected directions of further development of the noncontact techniques are indicated.

Guided waves in a stiffened composite laminate with a delamination

The integrity of safety-critical structural composites can be enhanced by the use of innovative ultrasonic nondestructive evaluation techniques. Among the various existing techniques, guided wave methods provide a good promise in terms of sensitivity to a variety of damage types or defects and the extent of the area that can be monitored, given the ability of these waves to travel relatively long distances within the structure under investigation. In comparison with isotropic metallic structures, wave propagation in composite structures presents additional complexity for effective damage identification. The material inhomogeneity, anisotropy, and the multilayered construction of composite materials lead to significant dependence of wave modes on laminate layup configurations, direction of propagation, frequency, and interface conditions. In this article, a specific structure will be analyzed with different levels of complexities in an effort to determine the propagation characteristics of the waves. The investigated structure is a stiffened composite plate of finite thickness and infinite lateral dimensions. The work is carried out using theoretical analysis, numerical modeling, and laboratory experiments. Numerical (finite element) simulations are used for more realistic models, where the geometric and material complexities present practical difficulties in direct analysis using theoretical constructs only.

Monitoring of bitumen hardening with a non-destructive ultrasonic shear wave reflection technique

The article presents a possibility of using a non-destructive ultrasonic shear wave reflection technique for monitoring hardening process of bitumen. The technique relies on the use of a new measuring instrument called USWR-4 Hardening meter, which was developed to be applicable directly in situ and has been effectively used for cement-based materials so far. It works on the principle of continuous measurement of change of a shear wave reflection coefficient. Three different types of paving grade and two polymer-modified bitumens were used. Results show that the presented ultrasound technique can effectively track a temperature-dependent hardening process of bitumen.

Simulation study of a chaotic cavity transducer based virtual phased array used for focusing in the bulk of a solid material

In acoustic and ultrasonic non-destructive testing techniques, it is sometimes beneficial to concentrate sound energy at a chosen location in space and at a specific instance in time, for example to improve the signal-to-noise ratio or activate the nonlinearity of damage features. Time Reversal (TR) techniques, taking advantage of the reversible character of the wave equation, are particularly suited to focus ultrasonic waves in time and space. The characteristics of the energy focusing in solid media using principles of time reversed acoustics are highly influenced by the nature and dimensions of the medium, the number of transducers and the length of the received signals. Usually, a large number of transducers enclosing the domain of interest is needed to improve the quality of the focusing. However, in the case of highly reverberant media, the number of transducers can be reduced to only one (single-channel TR). For focusing in a non-reverberant medium, which is impossible when using only one source, an adaptation of the single-channel reciprocal TR procedure has been recently suggested by means of a Chaotic Cavity Transducer (CCT), a single element transducer glued on a cavity of chaotic shape. In this paper, a CCT is used to focus elastic energy, at different times, in different points along a predefined line on the upper surface of a thick solid sample. Doing so, all focusing points can act as a virtual phased array transducer, allowing to focus in any point along the depth direction of the sample. This is impossible using conventional reciprocal TR, as you need to have access to all points in the bulk of the material for detecting signals to be used in the TR process. To asses and provide a better understanding of this concept, a numerical study has been developed, allowing to verify the basic concepts of the virtual phased array and to illustrate multi-component time reversal focusing in the bulk of a solid material.