Velocity Of Longitudinal Ultrasonic Waves Research Articles

Experimental and theoretical elastic moduli of sodium–zinc–tellurite glasses

70TeO2-(30-x)ZnO-xNa2O, x = 0, 3, 7, 10 and 15 mol% glasses were prepared. Samples amorphousity has been checked by XRD. Density and molar volume have been estimated. Longitudinal and shear ultrasonic wave velocities were measured by using pulse echo technique. Elastic moduli (bulk, shear, longitudinal, Young's), Poisson’s ratio, Debye temperature, microhardness and softening temperature of the glasses were measured. Theoretical analysis of the elastic moduli has been achieved. Bond compression (B.C) and Makishima - Mackenzie (M.M) models have been used to interpret the experimental data of elastic moduli.

Elastic and attenuation behavior of the Bi1-x Re x FeO3 (x = 0 & 0.1; Re = La, Pr, Nd & Sm) multiferroic system

ABSTRACT A series of single-phase rare earth-doped bismuth ferrites were prepared by the solid state reaction method. After characterizing the samples with XRD, the bulk density measurements were carried out by the immersion method. The ultrasonic longitudinal (Vl ) and shear (Vs ) wave velocities were measured using 1 MHz quartz transducers with the help of the pulse transmission technique. Using the ultrasonic velocity values, Young’s and rigidity moduli along with Poisson’s ratio and Debye temperatures were calculated. As the materials are porous, the zero porous moduli have also been calculated using the Hasselman and Fulrath model. The observed variation of elastic moduli with different dopants has been explained qualitatively. The low-temperature behavior of ultrasonic longitudinal (Vl ) wave velocities was also measured. A small change of slope was observed at 208 K in BFO, BLFO and BSFO samples. Finally, the ultrasonic attenuation coefficient values of all the samples were also measured.

Lamination and Its Impact on the Physical and Mechanical Properties of the Permian and Triassic Terrestrial Sandstones

The sandstones with a laminated structure are common building materials. Lamination is macroscopically expressed as colour and grain size variations observed both in the deposit and within individual beds; therefore, the properties of such sandstones are diverse depending on the spatial distribution of the binding mass and framework components. For the terrestrial sandstones of different genesis, four types of laminae have been distinguished based on petrographic studies. They have a siliceous binder or a mixed ferruginous–siliceous–argillaceous binder with different proportions of these components. In laminae of types I–III, the grain framework is built mainly of quartz grains, and in type IV, it is accompanied by numerous lithoclasts and feldspars. Knoop hardness and CERCHAR abrasivity were tested in each lamina variety, and the results were correlated with the equivalent quartz content and the longitudinal ultrasonic wave velocity measured perpendicular and parallel to the lamination. The proposed research methodology was not used in previous studies on terrestrial laminated sandstones. The results explain a strong dependence between mineral composition, structure of laminae, and technical parameters of rocks. The knowledge of this relationship facilitates the selection of rocks that meet the relevant technical requirements and helps to optimally manage the resources of sandstone deposits.

Elastic and Attenuation Studies of Some Rare Earth Substituted Multiferroic Bismuth Ferrites

A series of rare earth substituted bismuth ferrites are prepared without any detectable impurity phase, by the solid‐state reaction method. The structural characterization of the samples is conducted using X‐ray diffraction (XRD) and bulk density studies. Later, the ultrasonic longitudinal (Vl) and shear wave (Vs) velocities are measured by the pulse transmission technique and using these values, the elastic moduli are calculated. As the materials are porous, zero porous elastic moduli have been computed using Hasselmann and Fulrath model. It is observed that the elastic moduli of samples are found to increase continuously with decreasing of ionic radii of the substituted element and the observed behavior is explained qualitatively. Finally, the attenuation coefficient values of all the samples are also calculated and are found to increase with decreasing of ionic radii of the rare earth substituted ion.

Physical and mechanical properties of ternary Ge-Se-Sb glasses for near-infrared applications

Many physical properties such as the average coordination number (CN), the compactness (δ), the overall bond energy (〈E〉), the cohesive energy (CE), the mean bond energy (E s), and the overall electronegativity difference (Δχ) as well as the degrees of ionicity (Ion) and covalency (Cov) were estimated theoretically. The chemical bond approach (CBA) was used to predict the type and proportion of the formed bonds in the studied glasses. Consequently, several structural and physical properties have been estimated. The results show that the studied glasses are rigidly connected, having an average coordination number increase from 2.41 to 2.61. Two approaches have been successfully used to estimate the band gap (E g) theoretically compared with the previously published experimental values for the Ge18Se82−xSbx (5 ≤ x ≤ 25 at. %) glasses. Values of E g decrease from 1.59 to 1.15 eV by an increase of the Sb content from 5 to 25 at. %. i.e. the wavelengths corresponding to E g values lie in the near-infrared range of spectra, which make these glasses candidates for the near-infrared applications. Furthermore, the ultrasonic longitudinal (v L ) and shear wave (v T ) velocities propagating through the glasses have been used to estimate the mechanical parameters such as the elastic bulk modulus, Poisson’s ratio, Young’s modulus, micro-hardness, and temperature of Debye. It was found that a change in slope occurs for various physical, mechanical, and structural properties near the stoichiometric composition (x ≈ 18 at. %) at which the glass structure consists of heteropolar bonds only.

A Non-destructive Ultrasonic Testing Approach for Measurement and Modelling of Tensile Strength in Rubbers

Currently, non-destructive testing is widely used to investigate various mechanical and structural properties of materials. In the present study, non-destructive ultrasonic testing was applied to study the relationship between the tensile strength value and the velocity of longitudinal ultrasonic waves. For this purpose, fourteen specimens of composites with different formulations were prepared. The tensile strength of the composites and the velocity of longitudinal ultrasonic waves inside them was measured. The relevance vector machine regression analysis, as a new methodology in supervised machine learning, was used to define a mathematical expression for the functional relationship between the tensile strength and the velocity of longitudinal ultrasonic waves. The accuracy of the mathematical expression was tested based on standard statistical indices, which proved the expression to be an efficient model. Based on these results, the developed model has the capability of being used for the online measurement of the tensile strength of rubber with the proposed formulation in the rubber industry.

Ultrasonic evidence of temperatures characteristic of relaxors in PbFe2/3W1/3O3–PbTiO3 solid solutions near the morphotropic phase boundary

We present an ultrasonic study of relaxor-based solid solution (1−x) PbFe2/3W1/3O3–x PbTiO3 (0.25 ≤ x ≤ 0.35) located within the morphotropic phase boundary (MPB). The longitudinal ultrasonic wave velocity and attenuation have been measured by the ultrasonic pulse-echo technique at a frequency of 10 MHz in a wide temperature range from 200 to 800 K. Attenuation peaks have been observed at characteristic temperatures, namely, at Burns temperature TB and the additional distinctive temperature T*. To explain the experimental results, we consider a modified polar nanoregions (PNRs) model taking into account fluctuation corrections of ultrasonic wave velocity and attenuation in the vicinity of both TB and T*. The obtained results confirm the dynamic nature of MPB effects which determine the physical properties of relaxor-based solid solutions.

Influence of samarium on some acoustical, physical and radiation shielding characteristics of Bi2O3–ZnO–PbO glasses

Bi2O3–ZnO–PbO glass formulations with various concentrations of samarium oxide Sm2O3 were synthesized using the rapid-quenching route. The deconvoluted FTIR spectra were recorded through the domain of 400–2000 cm−1. System characteristics including density as well as molar volume have been studied. Ultrasonic longitudinal and shear wave velocities and elastic moduli were found to reduce with Sm2O3 concentration. Both bulk compression and Makishima–Mackenzie models were found to diminish with the increase of Sm2O3 and in good harmony with the experimental results. Theoretical radiation shielding properties have been analyzed for the obtained glass system and showed high tendency to be used as radiation protection fabrics for γ rays.

Identification of Stress States in Compressed Masonry Walls Using a Non-Destructive Technique (NDT).

The structure safety can be assessed, but only indirectly, by identifying material properties, geometry of structures, and values of loads. The complete and comprehensive assessment can be done only after determining internal forces acting inside structures. Ultrasonic extensometry using an acoustoelastic effect (AE) is among the most common non-destructive techniques (NDT) of determining true stresses in structures. Theoretical bases of the method were described in the mid 20th century. They were founded on the correlation between ultrasonic waves and the value and direction of stresses. This method is commonly used to determine stresses mainly in homogeneous materials without any inherent internal defects. This method is rarely applied to porous or composite materials, such as concrete or rock due to a high dispersion of results. Autoclaved aerated concrete (AAC), characterized by high homogeneity and porosity, is the popular material in the construction sector, used to produce masonry units. The discussed tests involved the acoustoelastic effect to determine stresses in the masonry wall made of AAC. This paper presents a widely theoretical background for the AE method, and then describes the author’s own research on AAC divided into two stages. At first, the empirical relationships between compressive stress and velocity of longitudinal ultrasonic wave, including humidity, were determined. In stage II, nine masonry walls were tested in axial compression. Mean compressive stresses in the masonry wall determined with the proposed method were found to produce a satisfactory confidence level up to ca. 50% of failure stresses. Results were significantly understated for stresses of the order of 75% of failure stresses.

An Ultrasonic Longitudinal Through-Transmission Method to Measure the Compressive Internal Stress in Epoxy Composite Specimens of Gas-Insulated Metal-Enclosed Switchgear

Situations of internal stress in basin insulators inside gas-insulated metal-enclosed switchgear (GIS) can lead to cracks, which can influence the safety and stability of apparatus. However, there is currently no research on internal stress measurements for composites of GIS basin insulators, and only measurements for surface stress. In this paper, an internal stress measurement method for GIS epoxy composite is proposed using an ultrasonic longitudinal through-transmission technique based on the acoustoelastic effect. An internal stress measurement system is developed to investigate the relationship between the uniaxial compressive internal stress and the velocity of the ultrasonic wave vertical to the stress in epoxy composite within a range of 0–70 MPa, and to calculate the acoustoelastic coefficient of epoxy composite. The effects of system delay are eliminated in measuring the propagation time. Some epoxy composite cuboid specimens with similar materials and using a manufacturing process similar to those of 252 kV GIS basin insulators are synthesized, and the uniformity of the internal stress in cuboid specimens is verified by finite element simulation. The results reveal a linear increase of the ultrasonic longitudinal wave velocity with increasing stress. It has been shown that the average acoustoelastic coefficient of GIS epoxy composites, using the longitudinal waves vertical to the stress, is 4.556 × 10−5/MPa. Additionally, the absolute errors of the internal stress measurements are less than 12.397 MPa. This research shows that the ultrasonic method based on the acoustoelastic effect for measuring the internal stress in GIS epoxy composites is feasible.

Ultrasonic measurement and elastic properties of the PbO-SrO-B2O3 glass system

ABSTRACT: The PbO-SrO-B2O3 glass system with the of molar ratio of R (= PbO/B2O3) were prepared by fusion method. The elastic properties have been investigated using longitudinal and transversal ultrasonic wave velocity. Measurements were performed at room temperature and using pulse-echo technique at frequency of 5 MHz. The results indicate that, when increasing R value, the glass network stability decreases. This decrease indicates, of the increase the number of borate structures with non bridging oxygen (NBOs) at the expense of the decrease of borate units with tetrahedral structures. This feature may lead to the more open glass network structures and lower stiffness of the samples studied.

Elastic and spectroscopic properties of 0.7TeO2–0.1ZnO–0.1NaF–(0.1–x) WO3−xNd2O3 tellurite glasses

New tellurite glasses in the composition of 0.7TeO2–0.1ZnO–0.1NaF–(0.1–x) WO3−xNd2O3 and x = 0.005, 0.01, 0.015, 0.025, 0.035, 0.04 and 0.05 mol% were prepared. Density (ρ) and molar volume (Vm) have measured and calculated. Longitudinal and shear ultrasonic wave velocities (Ul, Us) were measured by the pulse-echo technique using Krautkramer USIP 20 at 4 MHz. Moduli of elasticity, longitudinal modulus (L), shear modulus (G), bulk modulus (K), Young’s modulus (E) and Poisson’s ratio (σ) were calculated for every glass sample. The UV spectra in the range 200–2500 nm were measured. The Judd–Ofelt intensity parameters Ωλ (λ = 2, 4, 6) were measured for the whole glass series. The Judd–Ofelt intensity parameters were in the order Ω2 < Ω4 < Ω6 for all Nd3+-doped tellurite glasses. Both oscillator strengths, experimental and calculated (fexp and fcal) from the ground state 4I9/2, were measured. Also, lifetime (τ) and ranching ratio (β) were calculated for each parentage of Nd2O3. Discussion was built on Judd–Ofelt parameters and the dissociation energy of bonds.

Influence of native structural defects activated by illumination and under the memory effect conditions on ultrasonic wave propagation in TlInS2 ferroelectric–semiconductor with incommensurate phase

This paper presents data about experimental observation and theoretical validation effect of native defect states activated by illumination and under the memory effect conditions on the velocity of longitudinal and shear elastic waves propagating in layered TlInS2 ferroelectric-semiconductor in different directions. These longitudinal and transverse ultrasonic velocities were worked out by using the pulse echo overlap technique in the range of temperature ∼90–300 K and correspond to and elastic constants of TlInS2. The investigations reveal the illumination-induced spike-like peaks in the temperature dependence of longitudinal wave velocity centered at different temperatures in the range of temperature 225–300 K of high-temperature paraelectric phase. The temperature dependence of ultrasonic velocity of shear wave corresponding to mode exhibits a steep decrease in the slope under illumination at ∼190 K. Influence of the memory effects on the velocities of ultrasonic waves, which is associated with annealing times of about five hours inside the incommensurate (INC) phase, show similar features in the same temperature ranges: a similar well-defined spike-like anomalies in the temperature dependence of longitudinal ultrasonic wave velocity at and pronounced shear acoustic-mode softening below ∼190 K. The experimental results have been discussed in the frame of phenomenological the Landau phase transition theory. It has demonstrated that native deep level defects and crystal imperfections charged under light excitation and the memory effect condition and may essentially distort a crystal lattice of TlInS2 in the high-temperature paraelectric phase.

High throughput rapid detection for SLM manufactured elements using ultrasonic measurement

Both pore parameters and elastic properties are important for the elements manufactured by the Selective Laser Melting (SLM) technology; however, their measurements are usually destructive and time-consuming. Thus, the ultrasonic longitudinal and transverse wave velocities (dual-mode velocities) method is extended here; then it is combined with the longitudinal wave attenuation to develop an ultrasonic high throughput rapid detection for SLM manufactured elements. As the focal transducer is used, a multi-Gaussian beam model is introduced to correct the diffraction attenuation. Twenty-eight parameters can be obtained by a single ultrasonic experiment, including the pore parameters and their distributions, the two-point spatial correlation function, and the Young’s modulus. Ti-6Al-4V samples with different porosities manufactured by SLM technology are used to conduct the ultrasonic experiment. The experimental results agree well with the results of metallographic, tensile experiment and micro-CT results. This method provides a useful tool for nondestructively, rapidly and accurately evaluating the pore parameters and elastic properties of SLM manufactured elements.

Local Kramers–Kronig Relations between the Attenuation Coefficient and Phase Velocity of Longitudinal Ultrasonic Waves in Polymer Composites

The relationship between the experimentally obtained attenuation coefficient and dispersion of the phase velocity of longitudinal ultrasonic waves in polymer composite materials has been analyzed. The laser optoacoustic method has been used to measure the ultrasonic attenuation and velocity in a wide frequency range. Verification of the Kramers–Kronig relations for ultrasound-scattering and absorbing carbon fiber reinforced plastic (CFRP) composites has been performed using the analysis of the relationship between the frequency dependences of the attenuation coefficient and phase velocity of longitudinal acoustic waves in samples. We have shown that the Kramers–Kronig relations between the ultrasonic attenuation and phase velocity are valid within the 1–10 MHz frequency range without regard to a particular mechanism of the decay in the energy of an initial acoustic wave during its propagation in a composite.

Prediction of uniaxial compressive strength of carbonate rocks from nondestructive tests using multivariate regression and LS-SVM methods

Uniaxial compressive strength (UCS) value of a rock material is one of the most important design parameters in engineering practice and related fields of geosciences. Through this importance, prediction of UCS values of rock materials from nondestructive quicker and simpler tests are widely preferred. The aim of this study is to predict the UCS values of five carbonate rock groups including marble, dolomite, two limestones, and travertine from longitudinal ultrasonic wave velocity (Vp), Schmidt hardness rebound number (SHR), and cubic sample sizes (L). For this aim, a total of 90 cubic samples with 7, 9, and 11 cm edge sizes were prepared. Chemical, petrographical, and basic physical properties of the sample groups were investigated. After Vp and SHR values, UCS values of all samples were determined. By using multivariate regression analyses (MR), different UCS prediction equations from dry unit weight (γd), Vp, SHR, and also L values were proposed. Prediction performances of proposed model in which Vp, SHR, and L are input parameters was also analyzed by least square support vector machines (LS-SVM) method. Prediction performances of the MR and LS-SVM models were analyzed by coefficient of determination (R2), efficiency (E), and root mean square error (RMSE) performance measures. These values were calculated as 0.867, 0.799, and 16.616 respectively for the LS-SVM model and 0.781, 0.749, and 18.561 respectively for the MR model. The LS-SVM method was found to be successful in the prediction of the UCS values from nondestructive test data of carbonate rocks.

A novel device for measuring the ultrasonic wave velocity and the thickness of hyperelastic materials under quasi-static deformations

An innovative low-cost testing machine for measuring simultaneously the ultrasonic longitudinal wave velocity and the thickness of hyperelastic material specimens, while applying a quasi-static deformation, is described. In a pulse-echo ultrasonic immersion test, both of these parameters can be obtained by measuring several times of flight, once the speed of sound in the coupling fluid at the testing temperature is known. The variation in ultrasonic longitudinal wave velocity through the sample when the deformation changes is called the acoustoelastic effect. Knowledge of this effect allows the material characterization. The results obtained on SBR-1502 reinforced with carbon black (20%) are in accordance to the values presented in literature and thus confirm the validity of the proposed experimental device.

Electrophysical and mechanical properties of PZT-based soft ferroelectric material in wide range of temperatures

The electrophysical and mechanical properties of a piezoceramic material based on a PZT are studied. Several features in the behavior of the electrophysical properties of the material in the temperature range located substantially lower than the low-frequency (1 kHz) maximum of the permittivity are revealed. The obtained results indicate the closeness of the material studied to ferroelectrics-relaxors, in particular, due to the low coercive field significant dependence of on the frequency and amplitude of the measuring field, and also the behavior of the velocity of longitudinal ultrasonic waves in the studied ceramics.

ВИЗНАЧЕННЯ ДИНАМІЧНИХ МОДУЛІВ ПРУЖНОСТІ ПОЛІМЕРНИХ АУКСЕТИКІВ ЗА ДОПОМОГОЮ ІМПУЛЬСНИХ ІМЕРСІЙНИХ ВИМІРЮВАНЬ ШВИДКОСТЕЙ ПОШИРЕННЯ УЛЬТРАЗВУКОВИХ ХВИЛЬ

The method of measuring the propagation velocities of longitudinal and transverse ultrasonic waves and their absorption coefficients using the impulsive immersion method is presented. Determination of ultrasonic wave propagation velocities is based on the comparison of the results of direct measurements of the propagation time of the probe pulse through immersion fluid in the absence of a sample and in the presence of a sample between the emitter and the signal receiver. When measuring the velocity of a longitudinal wave, the sample with strictly parallel surfaces is placed perpendicular to the direction of propagation of the wave in immersion liquids. The measurement of the velocity of the transverse ultrasound wave is based on the fact that when a longitudinal wave falls at a certain angle at the fluid separation line - the solid in the latter case generally propagates two waves: longitudinal and transverse. The method of rotating plate allows to determine the critical angle at which the longitudinal wave is transformed into the surface, and only the transverse wave propagates in the sample. According to the experimental values of the velocities of propagation of longitudinal and transverse ultrasonic waves, the Poisson's ratio of a number of metalfilled polymer auxetics with a polyurethane matrix was calculated. Determination of absorption coefficients of longitudinal and transverse ultrasonic waves as they pass through samples of the studied materials. Calculations of real and imaginary parts of complex dynamic modulus of elasticity: Young's modulus, shear modulus, bulk deformation modulus and mechanical loss tangent for longitudinal, transverse and bulk deformations. The obtained results indicate the possibility of using the impulsive immersion method in measuring the velocity of propagation of ultrasonic waves to determine the Poisson's ratio and the dynamic modulus of elasticity of polymer auxetics.

Effect of Density and Propagation Length on Ultrasonic Longitudinal Wave Velocity in Some Important Wood Species Grown in Turkey

In solids, density is an important factor that determines lots of properties such as mechanic behavior. Mechanic properties of materials can be determined by static and dynamic tests. Ultrasonic measurements are one of the non-destructive test methods and are being applied to lots of field for determination of wide range of properties. When literature in wood science reviewed, it’s seen that researches did not make a consensus on the effect of density on ultrasonic wave velocity. Also, propagation length is another issue that has close relations with ultrasonic waves. From this point of view, effects of density and propagation length on ultrasonic longitudinal wave in Oriental beech, Scots pine, Black pine and Turkish red pine woods were investigated in this study. 20x20 cross-cut and 20, 30 and 40mm L direction samples were used to perform measurements. All samples acclimatized at 20±1 °C temperature and 65% relative humidity. Then, ultrasonic measurements performed using OLYMPUS EPOCH 650 flaw detector and 2.25MHz contact type transducers. According to the results, MC of the samples were calculated around 12% and up to 25.49% increase in velocity observed when sample length increased from 20mm to 40mm. Coefficients of determination between density and velocity were ranged from 0.78 to 0.94. Therefore, it’s concluded that both propagation length and density have positive effect on ultrasonic wave velocity in these woods.