Application Of Ultrasonic Technique Research Articles

Investigation on low velocity impact damage identification with ultrasonic techniques under different sensor network conditions

Direct or indirect damages due to foreign object impacts on aeronautical structures, represent a major concern. The problem potentially intensifies with the adoption of composite materials, especially due to Barely Visible Impact Damage (BVID). In this context, understanding whether an impact event gives rise to delamination or debonding is highly desirable in view of the optimization of the maintenance strategies and, at the same time, of the safety margins associated to the operation of the structures. One possible method to achieve this goal is that of integrating damage monitoring systems within the vehicle architecture itself. By doing so, in fact, the enhanced structural health state awareness allows the implementation of Predictive Maintenance philosophies and the possibility to detect damage with size/severity and indentation smaller than the BVID currently applied by design and certification. In this work, a simple and a stiffened carbon fiber panel are subjected to Low Velocity Impacts using falling masses to generate a structural damage. A sensor network made of Piezoelectric elements (PZT) allows the application of Ultrasonic techniques, to monitor the damaged structure and calculate signal related features called Damage Indexes (DIs). The DI capability to identify the damage is then thoroughly investigated, with specific reference to: (i) effect of signal averaging, (ii) effect of reduced sensor network configurations and (iii) effect of sensor faults.

Estimating mechanical state of AA2024 specimen under tension with the use of Lamb wave based ultrasonic technique

ABSTRACTExperimental results on application of ultrasonic technique utilizing Lamb waves for evaluation mechanical state of AA2024T3 specimens under tensile testing are presented. PZTs used as actuators and sensors were glued onto the specimen surface with epoxy adhesive. The set of static tensile tests with two frequencies of acoustic testing (50 kHz and 335 kHz) were performed. The recorded signals were processed to calculate the informative parameters (maximum envelope and 2nd central moment) in order to evaluate the changes of the stress-strain state of the specimen and its microstructure evolution. The relations between acoustic signal features and damages occurring during the loading allow determining the defectiveness of the structure and predicting its residual lifetime.

Ultrasonic evaluation of the pitch of periodically rough surfaces from back side

The geometrical features of internal surfaces are important parameters in the field of non-destructive testing such as corrosion inspection or artistic qualities of material surfaces. Although stylus profiling and optical scattering are commonly used for measuring both random and periodically rough surface topography, they are only applicable to accessible surfaces. However, there are many cases in which the surface to be evaluated is inaccessible. For example, integrity monitoring of inner surfaces of pipes is required to ensure proper functions and safeguard quality. Unfortunately, little attention has been paid to the measurement of inaccessible periodic surfaces. Since inaccessible surfaces do not permit contact or optical measurement, application of ultrasonic technique from back side is an appropriate candidate among others. In this paper, an ultrasonic pulse-echo technique is investigated to evaluate the pitch of periodically rough surfaces which is inaccessible or hidden on the back side. The pitch of back surface profile is evaluated based on the diffraction grating theory for oblique incidence of P-wave, SV-wave, and SH-wave. The applicability of the proposed technique was verified by both numerical simulation and experiment. It is found that the angle of incidence should be larger than 45° to enhance the accuracy. SH-wave shows better results compared with SV-wave due to the effect of mode conversion. Moreover, using SH-wave is an effective way for evaluation of the pitch because SH-wave is more sensitive than P-wave with shorter wavelength. On the other hand, P-wave is the best solution to obtain the highest resolution of measurement with higher signal to noise ratio.

Ultrasound propagation in concentrated random dispersions of spherical particles: Thermal- and shear-mediated contributions to multiple scattering

Ultrasonic techniques offer advantages for process monitoring for dispersions of colloidal or nano particles; such materials occur in a wide variety of process industries. However, the application of ultrasonic techniques has been limited by the inaccuracy of ultrasonic propagation models used to interpret the measurements (typically attenuation spectra). Multiple scattering models, such as the Lloyd and Berry model [Proc. Phys. Soc. London 91, 678 (1967)], have been used with great success in relatively dilute colloidal dispersions, but fail for higher concentrations, smaller particles, and low frequencies, primarily due to the neglect of thermal- and shear-mediated effects. We present a modified multiple scattering model that includes these thermal- and shear-wave contributions and explore their significance. The model develops work by Luppe, Conoir and Norris [J. Acoust. Soc. Am. 2012 (131) 1113) for compressional, thermal and shear wave propagation. We identify the dominant scattering contributions for emulsions [Pinfield, J. Acoust. Soc. Am. 136, 3008 (2014)] and suspensions and develop analytical forms for them. Numerical calculations demonstrate the contribution of the additional multiple scattering effects to the compressional wave speed and attenuation through the emulsion or suspension. The calculations are compared with previously published experimental data.

Applications of Ultrasonic Techniques in Oil and Gas Pipeline Industries: A Review

The diversity of ultrasound techniques used in oil and gas pipeline plants provides us with a wealth of information on how to exploit this technology when combined with other techniques, in order to improve the quality of analysis. The fundamental theory of ultrasonic nondestructive evaluation (NDE) technology is offered, along with practical limitations as related to two factors (wave types and transducers). The focus is limited to the two main techniques used in pipe plants: First, straight beam evaluation and second, angle beam evaluation. The depth of defect (DD) is calculated using straight beam ultrasonic in six different materials according to their relative longitudinal wave (LW) velocities. The materials and respective velocities of LW are: rolled aluminum (6420 m/s), mild steel (5960 m/s), stainless steel-347 (5790 m/s), rolled copper (5010 m/s), annealed copper (4760 m/s), and brass (4700 m/s). In each material eight defects are modeled; the first represents l00% of the material thickness (D), 50.8 mm. The other seven cases represent the DD, as 87.5% of the material thickness, 75%, 62.5%, 50%, 37.5%, 25%, and 12.5%, respectively. Using angle beam evaluation, several parameters are calculated for six different reflection angles (βR) (45°, 50°, 55°, 60°, 65° and 70°). The surface distance (SD), ½skip distance (SKD), full SKD, and 1½SKD,½sound path (SP) length, full SP, and 1½ SP are calculated for each βR. The relationship of SKD and SP to the βR is graphed. A chief limitation is noted that ultrasound testing is heavily dependent on the expertise of the operator, and because the reading of the outcome is subjective, precision may be hard to achieve. This review also clarifies and discusses the options used in solving the industrial engineering problem, with a comprehensive historical summary of the information available in the literature. Merging various NDE inspection techniques into the testing of objects is discussed. Eventually, it is hoped to find a suitable technique combined with ultrasonic inspection to deliver highly effective remote testing.

Non-Destructive Testing of Wood Defects Based on Ultrasonic Technology

The elm wood samples were tested by the technique of ultrasonic, and the testing results were analyzed by using the statistic software of SPSS. The results showed that the moister content of wood, wood crack, the sizes of holes and numbers of holes have significant influence on propagation parameters and dynamic modulus of elasticity. If there are holes or cracks in the propagation path, the propagation time will be longer, and the propagation velocity and wood modulus will decrease accordingly. The studying results of this paper will provide a sound background for the application of ultrasonic technique in detecting the inner defects of wood products and other wooden structures, and also offer important reference for testing the inner defects of old trees and ancient buildings.

Recursive Algorithm for the Effective Impedance of Multilayered Acoustic Losses Media

This paper describes a rapid algorithm for effective impedance in multilayered media. The layers are considered losses and have parallel interfaces. Recursive equations are developed and introduced that enable to calculate the effective impedance in compartments composed of any arbitrary number of layers. The calculations are carried out through an iterative process. Several important influence factors, that affect the multilayer acoustic absorber, are discussed. A simple algorithm is proposed, which allows to obtain qualitative knowledge of the behaviour of the frequency band with layer parameters. This technique can be used in different applications of ultrasonic techniques.

111 超音波法による転がり軸受の潤滑診断の可能性(セッション3 状態監視(2))

Evaluation of a lubrication condition of ball bearing becomes an important issue for safe operation of a machine. In this paper, an application of ultrasonic technique is attempted for a purpose of evaluating the lubrication conditions. Quantitative measurement of a dent size which forms the origin of flaking is important for an evaluation of lubrication conditions. The width of indentation having 0.45mm on a raceway surface of an inner ring becomes possible with the observation of the change in echo height reflected from a boundary surface between housing and outer ring of the ball bearing. Furthermore, it can be possible to evaluate an insufficiency of oil in ball bearing by the observation of reflection echo height variation from a contact surface of outer ring and ball. When a sufficiently oil is supplied to the inlet of contact surface between them, the echo height increases locally. However, degree of its increase becomes lower when oil supply is insufficient, and does not appear at all with running out of oil. A time lag between the bottom of valley in echo height variation and the sound axis of ultrasonic probe decreases gradually as supply of oil becomes insufficient, and it becomes zero by running out of oil at a contact surface.

Observation of lubrication conditions using an ultrasonic technique

AbstractEvaluation of lubrication conditions for a real frictional surface, such as a steel bearing, becomes an important issue for safe operation of a machine. In this paper, an application of ultrasonic technique is attempted for a purpose of evaluating the lubrication conditions. Ultrasonic waves emitted towards a hydrodynamic lubrication interface are reflected multiple times in oil film, and an echo height of reflected waves from the boundary is dependent on film thickness. The results of this study indicated that the ultrasonic technique is able to measure film thickness of approximately 50 nm in the case of a standstill surface having extremely small surface roughness. Furthermore, a potential for estimating the oil film thickness between a piston ring and cylinder is also indicated. In addition, in the case of a ball bearing, quantitative measurement of a size of dent, which forms the origin of flaking, is important for an evaluation of lubrication conditions. This becomes possible with an observation of a change in the echo height reflected from a boundary surface between a housing and an outer ring of the ball bearing. In this study, quantitative measurement of an indentation having 0.32 mm width on a raceway surface of an inner ring was achieved. Copyright © 2009 John Wiley & Sons, Ltd.

Nonsurgical management of endodontic mishaps in a case of radix entomolaris

Anatomic variations can significantly contribute to the incidence of endodontic mishaps. Perforations and separated instruments form the bulk of such mishaps. Furcal perforations are undesired complications of endodontic treatment, which result in the loss of integrity of the root and further destruction of the adjacent periodontal tissues. Mineral trioxide aggregate (MTA) is a promising material that has been successfully used to repair perforations. This clinical case demonstrates the use of MTA as a repair material for furcal perforation due to an iatrogenic error in radix entomolaris in the mandibular first molar. It also describes the application of ultrasonic technique in the retrieval of separated instrument from the same. Both clinical and radiographic follow-up showed a stable condition without any probing defect, ongoing root resorption, or furcal pathosis.

MEASUREMENT OF THIN OIL FILM THICKNESS USING ULTRASONIC TECHNIQUE

An application of ultrasonic technique is attempted for the purpose of measuring thin oil film thickness between two surfaces. The amplitude of the wave reflected from the boundary is vary depending on film thickness, because the ultrasonic wave emitted to the interface between two surfaces does multiple reflection and interference in oil film. Quantitative measurement of oil film thickness then can be possible. For instance, it is possible to measure the submicron film thickness which exists near the point contact formed by convex glass and plate with high frequency probe. And it is confirmed that the oil film thickness estimated from the echo height agrees with the film thickness decided by the curvature of the lens or obtained by the optical interference method, even if it is 100 nm. On the other hand, the thickness of oil film between cylinder and piston ring can be easily measured by setting the small ultrasonic probe on the back of piston ring. For example, the influence of the second ring and oil ring for the behavior of an oil film formed on a top ring is able to evaluate quantitatively. As mentioned above, it is cleared that quantitative evaluation of thin film thickness is possible with investigating the echo height obtained by ultrasonic wave pulse reflection method.

P-42 Measurement of lubrication condition and oil film thickness with using ultrasonic technique

An application of ultrasonic technique is attempted for the purpose of measuring film thickness between moving surfaces. The measurement of film thickness is possible only by setting the ultrasonic probe to one of the friction surface, and the drilling for installing the probe like a measurement using a displacement sensor is not conducted. The ultrasonic wave emitted to the hydrodynamic lubrication interface is reflected multiple in oil film, and the echo height of reflected wave from the boundary is dependent on film thickness. For example, the thickness of oil film between cylinder and piston ring can be easily measured only by setting the small ultrasonic probe on the back of piston ring. On the other hand, the echo height under the mixed lubrication region is mainly dependent on the solid contact area. Therefore, the load share rate at the solid contact parts can be estimated from observed echo height.

Application of Ultrasonic Technique in Multiphase Flows

Ultrasonic technique was used as a tool for phase holdup measurement in multiphase systems. A new statistical approach using fluctuations of the ultrasound signals was applied to simultaneously detect the dispersed phase holdups in gas−liquid−solid flows. These phase holdups, measured by two methodsthe ultrasonic technique and the applications of pressure transducers and conductivity probesagreed well. In the system of a high liquid velocity (above 14 cm/s), the ultrasonic technique still provided reliable results. The local phase holdups and their radial distribution were measured in gas−liquid−solid three-phase circulating fluidized beds at two different elevations. A nonuniform radial distribution and a uniform axial distribution of gas and solid phases were observed. The nonuniform radial distribution of solid holdup did not depend on the solid circulating rate. The radial distributions of both phase holdups became uniform with increasing liquid velocity.

Optimization of buffer rod geometry for ultrasonic sensors with reference path

Several applications of ultrasonic techniques are limited by the signal-to-noise ratio (SNR). Transducers in these applications usually operate in the pulse-echo mode. Many transducers, especially those for high temperatures, use buffer rods. Often a reference path is used to eliminate electrical and transducer drift. Interference of echo signals and noise causes errors of both amplitude and phase measurement of the detected echoes. In this paper we discuss the influence of major noise sources as a function of geometry and operating environment. The effects are studied using both experimental results and models. Although the results are applied to an ultrasonic density sensor operating in the pulse-echo mode, they are applicable to other pulse-echo mode transducers comprising homogeneous cylindrical buffer rods. This paper will show how the SNR of the density transducer was improved in a special time window from 34 to 72 dB by careful design.

Application of ultrasonic techniques, as a non- destructive method, for the evaluation of a sixteenth century wooden ceiling, in the Marqueses de la Algaba Palace, Seville

This paper exposes some of the results obtained by a group of investigators. Its main aspects are included in Paloma Rubio de Hita's Doctoral Thesis. The main object of this work has been the development of an experimental method by means of non-destructive techniques applied to timber structures. This way, the determination of damages, decay and bending strength of these timber structures will give a diagnosis for their rehabilitation. This investigation, supported by an important laboratory research, enables us to do works in situ with a knowledge of timber resistance characteristics related to the testing technique that we have used. This method has been applied to a very important historical building, the Palacio de los Marqueses de la Algaba, a palace located in Seville. Our study has been centred on a 16T century wooden ceiling, made of Pinus Sylvestris, that was aimed to be restored.

Theory and application of ultrasonic microstructural characterization

Ultrasonic microstructural characterization techniques have been developed for a variety of reasons ranging from process control to life extension. The techniques are based on principles of wave propagation and scattering from inhomogeneities. Applications of ultrasonic techniques include predicting sheet metal formability, controlling microstructure in metal-matrix composites, monitoring diffusion bonding, measuring porosity in castings and composites, and designing microstructures for enhanced inspectability.

Application of ultrasonic techniques to the measurement of spatial charge and electric field distributions in solid dielectric materials

Application of ultrasonic techniques to the measurement of spatial charge and electric field distributions in solid dielectric materials

Ultrasonics in food engineering Part II: Applications

Applications of ultrasonic techniques in the food industry are reviewed, relevant applications in other industries are considered and the future of ultrasonics in food engineering examined. Data on sound velocity and attenuation in food and food-related materials are tabulated, together with acoustically measurable properties such as adiabatic compressibility, rigidity and acoustic impedance. Measurement of sound velocity in vegetables, doughs and chocolate is described. Only low-power applications of ultrasonics of relevance to the measurement of food properties are considered.

固体中の電荷および電界分布測定への超音波の利用

固体中の電荷および電界分布測定への超音波の利用

Application of Ultrasonic Techniques to Study the Properties of Silicone Elastomers in High Pressure Gas Media

AbstractPolymers absorb large quantities of gas under high pressure. This process is usually accompanied by a significant volumetric strain and also by changes in the mechanical properties of the sample. We will describe how these properties may be studied by using an ultrasonic technique. The sorption and volumetric changes are progressive in nature following the application of an incremental increase or decrease in ambient pneumatic stress. These techniques are also used to follow the time dependent changes in both the linear strain and the mechanical properties of the system. Data will be cited for a range of nitrogen gas pressures up to 27 MPa at 20°C for a virgin Poly-dimethylsiloxane (PDMS) elastomer and for its composite with glass filler to exemplify the experimental and analytical procedures. The final section of the paper shows how the same techniques may be used to monitor the inception and progressive development of internal cracks during certain ambient gas decompression profiles.The information obtained provides a basis for better material selection and for the specification of the service life of particular materials in hostile environments.