Transmission Of Ultrasonic Waves Research Articles

Laboratory experiments on compressional ultrasonic wave attenuation in partially frozen brines

Often, the loss mechanisms responsible for seismic attenuation are unclear and controversial. We used partially frozen brine as a solid-liquid coexistence system to investigate attenuation phenomena. Ultrasonic wave-transmission measurements on an ice-brine coexisting system were conducted to examine the influence of unfrozen brine in the pore microstructure on ultrasonic waves. We observed the variations of a 150–1000 kHz wave transmitted through a liquid system to a solid-liquid coexistence system, changing its temperature from [Formula: see text] to –[Formula: see text]. We quantitatively estimated attenuation in a frequency range of [Formula: see text] by considering different distances between the source and receiver transducers. We also estimated the total amount of frozen brine at each temperature by using the pulsed nuclear magnetic resonance (NMR) technique and related those results to attenuation results. The waveform analyses indicate that ultrasonic attenuation in an ice-brine coexisting system reaches its peak at [Formula: see text], at which the ratio of the liquid phase to the total volume in an ice-brine coexisting system is maximal. Finally, we obtained a highly positive correlation between the attenuation of ultrasonic waves and the total amount of unfrozen brine. Thus, laboratory experiments demonstrate that ultrasonic waves within this frequency range are affected significantly by the existence of unfrozen brine in the pore microstructure.

A theoretical study of ultrasonic wave transmission through a fluid–solid interface

This article develops a model for the study of the transient ultrasonic waves radiated by a transducer in a liquid and transmitted into a solid through a plane interface. The method is an extension to the transient case, of the angular spectrum method previously developed for the monochromatic case. It is based on the decomposition of the ultrasonic field, in impulse plane waves. The radiated waveform is calculated at any point in the field by a simple summation of these impulse plane waves, where the propagation delay and the refraction have been taken into account. These plane waves are, first of all, delayed by an amount of time corresponding to the travel time up to the considered field point. The transmission through the plane interface is taken into account by using Snell refraction laws and transmission coefficients. In the obtained results all the waves previously described by other authors are highlighted: direct wave, edge waves, head waves as well as subsurface waves with a clear resolution between compression and shear waves.

On-line damage detection on a wing panel using transmission of multisine ultrasonic waves

Fatigue damage of materials is an important problem that causes a lot of failures in mechanical systems. It is very important to detect this fatigue as early as possible. Nowadays, most of the nondestructive testing methods are off-line: the inspection is carried out periodically and in some cases the device has to be dismounted. So we risk to exceed, for example, the critical length of a crack. In this article, an on-line method based on the variation in transmission of a multisine ultrasonic wave during opening and closing of a surface crack is developed. As a validation experiment, a propagation fatigue crack in a sinusoidally loaded wing panel is considered. It will be shown that the on-line method is very sensitive to crack propagation.

Experimental Study on Intermediate Layer Made of (0–3) Composite Materials for Use in Air-Coupled Ultrasonic Transducers

The (0–3) composite materials for the intermediate layer of a MHz-range air-coupled ultrasonic transducer were studied experimentally. The optimal value of the characteristic acoustic impedance for this intermediate layer was calculated using a transmission line model. The (0–3) composite materials were formed from a mixture of silicone rubber and hollow thermoplastic microspheres at various weight ratios, and their acoustic properties were measured, and compared with those of a Reuss model. The measured values of the acoustic properties of the composite materials agreed well with the theoretical estimation. The transmission and reception of an air-coupled ultrasonic waves of 1 MHz using a piezoceramic transducer fitted with the intermediate layer was demonstrated with a pulse–echo system, and the sensitivity was improved by 20 dB by using the optimal composite material.

The range equation of the ultrasonic link in gas media

The paper presents a few chosen issues concerning the conditions that must be met to render possible the effective use of ultrasonic waves in active and passive applications in various gas media. The basic parameters of the gas medium influencing the transmission of ultrasonic waves in this kind of medium were discussed. An analysis of the range equation of the ultrasonic coupler in the gas medium and the computer model of the link in the stationary medium conditions were presented. An equation for the level of power decrease in the link was formulated and the calculated and measured characteristics of the level of power decrease for a few ultrasonic transducers working in the band of 20–100 kHz were presented in graphs.

Ultrasonic detection of subsurface flaws

New experimental relationships of coefficients of reflection and transmission of ultrasonic waves in artificial surface and subsurface models of cracks have been obtained in a wide range of parameters.

Acoustic Emission (AE) and Nonlinear Elastic Wave Spectroscopy (NEWS) for Online Monitoring of Concrete Curing

An integrated system of dynamic nondestructive experiments for material process monitoring is proposed, consisting of a combination of the AE technique with Nonlinear Elastic Wave Spectroscopy (NEWS). Using this system, we evaluate the microstructural properties of freshly poured concrete during hydration, with the ultimate goal to correlate these properties to its long-term behavior. The integrated system allows online monitoring of the condition parameters, of the internal microstructural activity by continuously triggering AE events and of the linear and nonlinear elastic properties of the microstructure through ultrasonic pulsed and continuous wave transmission measurements at regular time intervals. The internal temperature readings, the evolution in the acoustic emission events and the behavior of the linear and nonlinear elastic properties can be related to the different stages in the hydration process of concrete. The data are analyzed as a function of the degree of hydration for various concrete compositions during the first three days of the hydration process.

空中超音波送波器の音響整合層のための粒子分散型複合材料の設計とその音響的特性

The acoustic properties of (0-3) composite materials for acoustic matching layer of MHz-range air-coupled ultrasonic transducer are studied experimentally. The composite materials are formed from a mixture of silicone rubber and hollow thermoplastic microspheres. The acoustic properties of the composite materials are measured and compared with Reuss model, which is theoretical model for elastic properties of composite materials. The measured values of velocity and characteristic acoustic impedance of the composite materials agreed well with the theoretical estimation up to 10% weight fractions of hollow thermoplastic microspheres. The optimal value of characteristic acoustic impedance for acoustic matching layer of air-coupled ultrasonic transducer was calculated using transmission line model. The acoustic matching layer having the optimal value was obtained from the composite material, for which the weight percentage of hollow thermoplastic microspheres is 5%. Transmission of air-coupled ultrasonic wave of 1 MHz using piezoceramic transducer with the acoustic matching layer is demonstrated, and the sensitivity of transmission was improved by 10 dB using the optimal composite material.

Ultrasonic wave transmission in periodically undulated plates

This study focuses on quantifying the change in phase speed of waves transmitting through periodically undulated plates under pass band interaction. A perturbation technique is used to analyze the transmission of horizontally polarized guided waves in elastic plates with sinusoidal periodicity at their outerfaces. Phase speed of transmitting modes is presented as a function of various parameters, including outerface wavenumber, undulation amplitude, degree of undulations symmetry about the periodically undulated plate midplane, plate average thickness, and frequency of propagation.

The influence of cortical end-plate on broadband ultrasound attenuation measurements at the human calcaneus using scanning confocal ultrasound

Quantitative ultrasound (QUS) assessment, including broadband ultrasound attenuation (BUA), is an efficient technique for assessing bone quality in various statuses, e.g., osteoporosis. While assessing trabecular bone loss is essential to bone quality, the existence of cortical bone can substantially reduce the accuracy of BUA measurement. In this study, we developed an approach to quantify the influence of the cortical end-plate in the QUS on 18 cadaver calcanei using both analytical and experimental analyses. A simplified cortical-trabecular-cortical sandwich model has been developed for simulation of wave propagations. Results show that the cortical end-plate has a significant effect on BUA (yielding 8.5 +/- 3.6 dB/MHz in cortical bone alone), approximately 15% of the BUA value over the whole bone BUA measurement (54.1 +/- 20.1 dB/MHz). The phenomenon has been predicted by the developed analytical model with a high correlation (r2 = 0.63, p < 0.0001). The data have suggested that the mechanism of the BUA attributed to the cortical end-plate is primarily due to the ultrasonic wave transmission and reflection within the cortical layers. Therefore, the influence of the cortical end-plate in BUA can be quantified and incorporated into the QUS assessment for bone quality, which may provide insight into BUA measurement for accurate diagnosis of bone diseases.

Comparison of tissue heating using 3 MHz ultrasound with T-Prep ® versus Aquasonic ® gel

Objective The purpose of this research was to compare Aquasonic ® and T-prep ® gel, a 1% methyl nicotinate preparation, in their ability to increase the temperature of soft tissue when used with 3 MHz ultrasound. Methods Thirty healthy participants (21–40 years of age) completed this IRB approved study. In the prone position, a 26 gauge, 4 cm thermistor was inserted 2.5 cm deep in the posterior calf. An OmniSound Unit was used to administer a 3 MHz treatment at 1.0 w/cm 2 in a 6 cm 2-defined area with a 2 cm 2 transducer. Temperature measurements were taken every 30 s for 15 min. On one calf, 5 cm 3 of Aquasonic ® gel was used as the coupling medium and on the other, 5 cm 3 of T-Prep ® gel was used. Results A repeated measures ANOVA was used to detect a significant difference over time but no significant difference was found between the coupling mediums. After 15 min, the T-Prep ® gel contributed to a 1.8 °C overall temperature increase compared to a 1.5 °C increase with Aquasonic ® gel. Conclusion The results of this 3 MHz study revealed that the acoustic transmission characteristics of the T-Prep ® and Aquasonic ® gels were similar at increasing tissue temperature at a depth of 2.5 cm. Given that there are numerous conducting mediums that have been shown to limit the transmission of ultrasonic waves, T-Prep ® may be an option to Aquasonic ® gel when tissue heating is desired. Further research on the depth of heating with T-Prep ® gel would be appropriate.

Comparison of ultrasonic wave transmission and reflection measurements with P- and S-waves on early age mortar and concrete

This paper reports on results of round robin tests comparing two nondestructive, ultrasonic techniques: the wave transmission method using P-waves and the wave reflection method using S-waves. The experiments were conducted within the activities of the RILEM Technical Committee TC ATC-185 with the objective to evaluate the ability of these methods to continuously monitor the setting and hardening process of cementitious materials. In total, eight different mortar and concrete mixtures were subjected to the ultrasonic tests. Additionally, experiments were conducted to determine the penetration resistance (ASTM C 403), the in-situ temperature rise, the adiabatic heat release, and the chemical shrinkage (of the cement paste phase) of the investigated materials. The results revealed that, originating from the different wave types, the two ultrasonic methods monitor the setting process of mortar and concrete in significantly different ways. Despite these differences, the comparison of the ultrasonic test results with the development of the adiabatic heat and the chemical shrinkage has proven that P-wave velocity and reflection loss, as the parameters measured by the two methods, have a consistent and direct relationship to the cement hydration process.

Comparison of ultrasonic wave transmission and reflection measurements with P- and S-waves on early age mortar and concrete

Comparison of ultrasonic wave transmission and reflection measurements with P- and S-waves on early age mortar and concrete

저장기간에 따른 사과 과육의 기계적 특성 및 초음파 파라미터

The potential use of ultrasonic technique for firmness measurement of apples was evaluated. Mechanical properties(bioyield deformation, bioyield strength, rupture deformation, ultimate strength, and elastic modulus) and ultrasonic parameters (ultrasonic velocity, attenuation coefficient and the first peak frequency) of the apple flesh during the storage time were measured and analyzed. Ultrasonic parameters were determined from the measurement of ultrasonic wave transmission through the apple flesh specimen. Mechanical properties were obtained by universal testing machine. The bioyield strength, rupture strength, elastic modulus, ultrasonic velocity, and the first peak frequency of the apple flesh decreased with the storage time. The bioyield deformation, rupture deformation, and ultrasonic attenuation coefficient increased with the storage time. The correlation analysis between ultrasonic parameters and mechanical properties and the storage time was performed. The high correlations were found between the storage time and the ultrasonic parameters, and these relationships seem to be useful for determining the firmness of the apple flesh.

Transient reflection and transmission of ultrasonic wave in cancellous bone

Cancellous bone is known to be poroelastic in structure. Ultrasonic wave propagation in cancellous bone can be formulated by using Biot’s equations. In this paper we present some results in our ongoing research on the reflection and transmission of ultrasonic waves in cancellous bone. We investigate the relations among reflected waves, transmitted waves and Biot coefficients. We present an algorithm for the determination of the porosity of cancellous bone.

PRF Adjustment method and apparatus, and ultrasonic wave imaging appartus

In order to obtain an optimum PRF, the velocity distribution of an echo source is calculated based on the Doppler shift of an ultrasonic wave echo, the profile of the velocity distribution is calculated ( 172 ), the reflection of the profile is corrected ( 174 ), the maximum value of the velocity in the corrected profile is detected ( 176 ), and the PRF of the ultrasonic wave transmission is adjusted based thereon ( 178 ).

Numerical method for determining ultrasonic wave diffusivity through coagulating milk gel system

An ultrasonic transmission system was used to measure transmission of ultrasonic waves through a coagulating milk system. Reconstituted skim milk was coagulated at different temperatures and rennet and calcium chloride concentrations. Ultrasonic wave diffusivity was determined based on experimental velocity and attenuation data. Wave diffusivity increased with decreasing milk fluidity as coagulation progressed. A finite difference model was developed to predict ultrasonic diffusivity based on the wave and diffusion equations. The numerical predictions compared well with the experimentally determined diffusivity values. However, the numerical values were always lower than their corresponding experimental values. This difference was apparently a result of energy loss at the transducer–milk gel interface, which was assumed to be zero for the numerical model.

Behavior of acoustic emission generation during tensile tests perpendicular to the plane of particleboard II: effects of particle sizes and moisture content of boards

Particleboard specimens with various particle sizes were conditioned into two ranges: low and high moisture content. One set was investigated for internal bond (IB) strength and acoustic emission (AE) events during tensile tests perpendicular to the plane and the other for ultrasonic wave transmission characteristics in the thickness direction. The particleboard structural mechanics were changed as a result of the moisture effect. Specimens conditioning to higher moisture content had lower IB strength and lower cumulative acoustic emission event counts (T AE). The decrease in IB strength indicated that the irreversible thickness swelling was seen when recovery forces of the particles exceed the restraining action of the adhesive. This was attributed to stress release, which resulted in internal failure of the board. The change in the internal structure caused an increased stress level at the initiation of AE generation. No events were recorded before this stress level, obeying theKaiser effect. The decrease inT AE was not only related to the decrease in IB strength but was also affected by the transformation (attenuation) of the AE signals during IB tests according to the mesh size used.

System and method of assessing the structural properties of wooden members using ultrasound

A system and method of detecting anomalies and/or grain variations in a wooden member. At least one ultrasonic transmitter (401) applies an ultrasound waveform into a surface of a wooden member (100) so as to generate a multiplicity of ultrasonic waves including, e.g., longitudinal and shear waves. These ultrasonic waves are measured after propagation through the wooden member by at least one ultrasonic receiver (402) disposed on the same surface of the wooden member. At least one ultrasonic receiver (501) may also be placed opposite the ultrasonic transmitter (401) so as to detect radial transmission of the longitudinal ultrasonic wave at a point across the wooden member. The received ultrasonic waves are processed to determine anomalies and/or grain variations in the wooden member at positions of the wooden member between the ultrasonic transmitter and the ultrasonic receiver(s). The ultrasonic transmitters and receivers the ultrasound may be placed in rollers to facilitate high-speed, in-line processing of wooden members.

Transmission and Detection of Ultrasonic Wave by Electromagnetic Acoustic Transducers. Effects of a Flaw in a Specimen.

Transmission and Detection of Ultrasonic Wave by Electromagnetic Acoustic Transducers. Effects of a Flaw in a Specimen.