Ultrasonic Pulse-echo Method Research Articles

Ultrasonic characterization of thermally grown oxide in thermal barrier coating by reflection coefficient amplitude spectrum

The thermally grown oxide (TGO) growth at the interface of ceramic coating/bond coating in thermal barrier coatings (TBCs) was evaluated by ultrasonic reflection coefficient amplitude spectrum (URCAS). A theoretical analysis was performed about the influence of acoustic impedance match relationship between the ceramic coating and its adjacent media on URCAS. The immersion ultrasonic narrow pulse echo method was carried out on the TBC specimen before and after oxidation under 1050°C×1h for 15cycles. The resonant peaks of URCAS obtained before and after oxidation showed that TGO which generated between the ceramic coating and bond coating due to the oxidation, changed the acoustic impedance match between the ceramic coating and its adjacent media. This method is able to nondestructively characterize the generation of TGO in TBCs, and is important to practical engineering application.

Sound speed estimation in single cells using the ultrasound backscatter power spectrum

The acoustic properties of single cells such as their size, sound speed and attenuation are known to change depending on the type, state, or disease progression of a cell. Typically, ultrasonic pulse echo methods on adherent cells are used. We propose using the ultrasound backscatter power spectrum on cells in suspension to extract the acoustic parameters. When the ultrasound wavelength is on the same order as the dimensions of the cell, periodically varying minima and maxima occur throughout the power spectrum that depend on the sound speed and density of the object and the surrounding fluid, respectively. The ultrasound parameters can be determined by comparing the measured spectrum to a theoretical scattering model. We measured the backscattered ultrasound signals from single MCF7 breast cancer cells in suspension using a 200 MHz transducer. The cell diameter was determined through simultaneous optical imaging. The sound speed was calculated by adjusting the parameters in the scattering model until a good fit of the spectral features between the model and measured agreed. The sound speed from single cells found to vary between 1540 to 1580 m/s when the density was fixed at 1050 kg/m3.

Why Multi shot should be conducted for Radiography Examination..?

Ultrasonic pulse echo method is approved for planar defect in the weld joint against radiography examination. The most important point in this evaluation is planar defects are effectively traced in radiography. Due to its excellent weldability, carbon steel is suitable for submerged arc welding. Ultrasonic and Radiography inspection is conducted for weld joint. During radiography method, planar defect (Lack of fusion) is detected and as verification ultrasonic pulse-echo method is also conducted to grasp planar defect. Primarily a demerit in radiography is shown as plus point in ultrasonic method. Secondarily, Lack of fusion is very common type of defect in weld defects. Lack of fusion is not notice as weld defect, as they are characterized as planar defect. As a final point, lack of fusion is not noticed by radiography examination, and may probably determine by ultrasonic method. The merits of Ultrasonic evaluation over X-ray Radiography inspection are discussed in these studies. Radiographic Testing (RT) or industrial radiography is a nondestructive testing (NDT) method of inspecting materials for hidden flaws by using the ability of short wavelength electromagnetic radiation (high energy photons) to penetrate various materials. Principle of radiography is differential absorptionand X-ray radiography can be used as source for detection of defectSince the amount of radiation emerging from the opposite side of the material can be detected and measured, variations in this amount (or intensity) of radiation are used to determine thickness or composition of material. Penetrating radiations are those restricted to that part of the electromagnetic spectrum of wavelength less than about 10 nanometer. Radiography defects such as planar cracks are difficult to detect using radiography; hence Ultrasonic is the preferred method for detecting this type of discontinuity.Ultrasonic pulse-waves of short wave length with center frequencies [3] ranging from 0.1-15 MHz and occasionally up to 50 MHz are launched into materials to detect internal flaws or to characterize materials.Radiography and ultrasonic inspection are the two generally non-destructive methods used in these investigations Non-destructive inspection methods that can [1] detect embedded flaws that are located well below the surface of the test part. Neither method is limited to the detection of specific types of internal flaws. In order to evaluate the stability of a casting component, the shape of a defect inside it is discriminating for the evaluation and acceptance criteria which shall be adopted. Defect shape is usually classified in two types; in volumetric defects, which the ratio between height and width is next to unity, and [7] in planar defects, whose width is indeed, very small with respect to the height. Radiography capability allows the inspection of internal mechanisms and enhances the detection of cracks and planar defects by manipulating the part to achieve the proper orientation for flaw detection. Sample preparation Surface preparation of weld According to the American Iron and Steel Institute (AISI) standards the series of steel used in this study is 10XX. So that low carbon steel contains [8] about 0.1%Carbon and microstructure consists of Pearlite and ferrite. Due to its excellent [9] weldability, sub-merged arc welding is used to join two carbon steel pieces. Typical uses of carbon steel are connecting rods, automobile body panels etc. The complete surfaces of the welds are examined by X-ray. It has to be adequately free from irregularities that may mask or interfere with the X-rays.

Ultrasonic arrays for quantitative nondestructive testing an engineering approach

The Ultrasonic Pulse-Echo inspection method is extremely capable of detecting cracks that limit the structural integrity of loaded technical components and systems. However, the applied principles of ultrasonic material testing do not in general allow the characterization of flaws and the required measurement of crack dimensions. Appropriate wave field data sampling at the scanned surface with the subsequent field reconstruction improves both the resolution and the contrast sensitivity of inspection results. We use arrays with elements adapted for the inspection task with an optimized arrangement and element apertures of point source character. First results have been received applying linear arrays that are promising for the quantitative assessment of flaws by high-resolved high contrast imaging of inspection results in real-time.

Detection of Chill in Thin Wall Spherical Graphite Cast Iron by Ultrasonic Pulse-Echo Method

Detection of Chill in Thin Wall Spherical Graphite Cast Iron by Ultrasonic Pulse-Echo Method

복합재 연소관의 초음파 결함 분석 프로그램 개발

초음파 결함 분석 프로그램은 초음파 반사법을 기반으로 초음파 신호처리 기법을 적용하여 개발되었고, FRP 층간분리 및 FRP/내열고무 미접착 결함을 정량적으로 측정할 수 있었다. 복합재 연소관에서 검출된 결함은 절단하여 전산화 단층촬영 및 영상 현미경으로 분석하였고, 결함 분석 프로그램의 결과와 일치하였다. 본 논문은 복합재 연소관의 초음파시험 데이터를 C-Scan 영상으로 변환하여 결함을 분석할 수 있는 프로그램 개발 과정을 기술하였다. A defect analysis program for a composite motor case was developed to apply the ultrasonic signal processing method, based on the ultrasonic pulse-echo method. With the proposed defect analysis program, defects of FRP delamination and FRP/Rubber disbond in the composite motor case could be quantitatively measured. The defects detected in the composite motor case were in good agreement with the results measured with the computed tomography and video microscope. This paper described the development process of the defect analysis program to convert the ultrasonic test data into the C-Scan images.

Relationship between elastic and mechanical properties of dental ceramics and their index of brittleness

The purpose of the study was to verify the effects of a number of materials’ parameters (crystalline content; Young's modulus, E; biaxial flexure strength, σi; Vickers hardness, VH; fracture toughness, KIc; fracture surface energy, γf; and index of brittleness, B) on the brittleness of dental ceramics. Five commercial dental ceramics with different contents of glass phase and crystalline particles were studied: a vitreous porcelain (VM7/V), a porcelain with 16vol% leucite particles (d.Sign/D), a glass-ceramic with 29vol% leucite particles (Empress/E1), a glass-ceramic with 58vol% lithium-disilicate needle-like particles (Empress 2/E2), and a glass-infiltrated alumina composite with 65vol% crystals (In-Ceram Alumina/IC). Discs were constructed according to manufacturers’ instructions, ground and polished to final dimensions (12mm×1.1mm). Elastic constants were determined by ultrasonic pulse-echo method. σi was determined by piston-on-3-balls method in inert condition. VH was determined using 19.6N load and KIc was determined by indentation strength method. γf was calculated from the Griffith–Irwin relation and B by the ratio of HV to KIc. IC and E2 showed higher values of σi, E, KIc and γf, and lower values of B compared to leucite-based glass-ceramic and porcelains. Positive correlations were observed for σi versus KIc, and KIc versus E1/2, however, E did not show relationship with HV and B. The increase of crystalline phase content is beneficial to decrease the brittleness of dental ceramics by means of both an increase in fracture surface energy and a lowering in index of brittleness.

Flexural strength and failure modes of layered ceramic structures

Objective To evaluate the effect of the specimen design on the flexural strength ( σ f ) and failure mode of ceramic structures, testing the hypothesis that the ceramic material under tension controls the mechanical performance of the structure. Methods Three ceramics used as framework materials for fixed partial dentures (YZ – Vita In-Ceram YZ; IZ – Vita In-Ceram Zirconia; AL – Vita In-Ceram AL) and two veneering porcelains (VM7 and VM9) were studied. Bar-shaped specimens were produced in three different designs ( n = 10): monolithic, two layers (porcelain-framework) and three layers (TRI) (porcelain-framework-porcelain). Specimens were tested for three-point flexural strength at 1 MPa/s in 37 °C artificial saliva. For bi-layered design, the specimens were tested in both conditions: with porcelain (PT) or framework ceramic (FT) layer under tension. Fracture surfaces were analyzed using stereomicroscope and scanning electron microscopy (SEM). Young's modulus ( E) and Poisson's ratio ( ν) were determined using ultrasonic pulse-echo method. Results were statistically analyzed by Kruskal–Wallis and Student–Newman–Keuls tests. Results Except for VM7 and VM9, significant differences were observed for E values among the materials. YZ showed the highest ν value followed by IZ and AL. YZ presented the highest σ f . There was no statistical difference in the σ f value between IZ and IZ-FT and between AL and AL-FT. σ f values for YZ-PT, IZ-PT, IZ-TRI, AL-PT, AL-TRI were similar to the results obtained for VM7 and VM9. Two types of fracture mode were identified: total and partial failure. Significance The mechanical performance of the specimens was determined by the material under tension during testing, confirming the study hypothesis.

Synthesis of (α- and β-)Si 3N 4/Si 2N 2O into silicon particulate porous preforms by hybrid system CVI and direct nitridation

An investigation on the microstructure and mechanical properties of Si/Si 3N 4/Si 2N 2O porous ceramic composites, synthesized in a multi-step approach via hybrid precursor system chemical vapor infiltration (HYSYCVI) and direct nitridation (DN) has been conducted. Particulate silicon porous preforms were infiltrated in subsequent stages S1-1, S1-2 (both at 1300 °C for 70 min in high purity nitrogen (HPN) using Na 2SiF 6 as solid precursor) and S2 (1350 °C for 120 min in ultra high purity nitrogen (UHPN)). Chemical reactions that account for the formation of Si 2N 2O and Si 3N 4 are proposed. Results show that the microstructure of the composites was influenced by atmosphere type and processing stage, affecting kind, morphology and size (including nanometric size) of nitrides formed. Porous composites (43% porosity) with modulus of rupture (MOR) ≈ 43 ± 3.5 MPa (evaluated in four-point bending tests) and elastic modulus ( E) ≈ 29 GPa (determined by the pulse-echo ultrasonic method) are routinely obtained.

Ultrasonic evaluation of TiAl and 40Cr diffusion bonding quality based on time-scale characteristics extraction

To solve the problem of ultrasonic pulse-echo method in the evaluation of kissing bond and unbond in TiAl and 40Cr diffusion bonding, a characteristics extraction algorithm was proposed. The algorithm was based on continuous wavelet transform to convert ultrasonic TiAl and 40Cr diffusion bonding interface signals into time-scale domain. The ultrasonic tests were performed by an ultrasonic C-scan imaging system using a 10 MHz focused transducer. The time-scale amplitude and phase of the interface signals were calculated and analyzed to distinguish the kissing bond and the unbond from the perfectly bonded interface. The kissing bond can be detected by the scale-dependent amplitude combined with phase variation and the unbond can be measured by the opposite phase. The amplitude and phase characteristics were extracted to reconstruct the amplitude and phase characteristics images for TiAl and 40Cr diffusion bonding specimens evaluation. The amplitude and phase characteristics images are effective in the evaluation of bonding quality.

Quadrupole Effects of Layered Iron Pnictide Superconductor Ba(Fe0.9Co0.1)2As2

Elastic constant measurements on iron pnictide Ba(Fe 0.9 Co 0.1 ) 2 As 2 with an optimal superconducting transition temperature of T SC = 23 K have been performed by the ultrasonic pulse echo method. The shear elastic constant of C 66 associated with elastic strain e x y reveals considerable softening of 21% below 300 K down to T SC and becomes increasing in the superconducting phase below T SC , while other shear elastic constants of ( C 11 - C 12 )/2 and C 44 show no sign of softening below 80 K down to 4.2 K. The electric quadrupole O v ' existing in the degenerate d y ' z and d z x ' bands participates in the superconductivity of the present iron pnictide system.

619 ピエゾフィルムを用いたスマートレイヤからの超音波多点送受信によるき裂同定(GS-3 材料検査および評価)

619 ピエゾフィルムを用いたスマートレイヤからの超音波多点送受信によるき裂同定(GS-3 材料検査および評価)

ICONE19-44019 LIQUID FILM THICKNESS MEASUREMENT IN SMALL SQUARE PIPE USING ULTRASONIC PULSE-ECHO METHOD

The ultrasonic pulse-echo method is applied to measure thickness in a liquid film. To prevent a piezoelectric element cracking under high temperature conditions, the maximum frequency of sound is limited. On the other hand, the required thickness resolution is about 0.05mm to detect whether or not dryout has occurred. An ultrasonic transducer frequency of 5MHz is selected to satisfy both frequency and resolution requirements for air-water experiments. The changing liquid film thickness on a stainless steel plate is simultaneously measured with the ultrasonic transducer and a laser displacement sensor. The two types of results show good agreement within the range from 0.06 to 0.22mm. Next, the air-water annular flow in the small vertical square pipe is measured using the pulse-echo method. A liquid film sensor based on the electrical conductance method is also used for results comparison. The most frequently observed thickness measured by the two methods is almost the same based on comparison of the measurement histograms. To estimate the resolution of the pulse-echo method, the pulse intensities of multiple reflections in the liquid film are simulated. The results show that a liquid film thickness of 0.03mm can be measured even if the ultrasonic frequency is less than 5MHz.

Observations of fluid-dependent shear-wave splitting in synthetic porous rocks with aligned penny-shaped fractures‡

P- and S-wave velocity and attenuation coefficients (accurate to ±0.3% and ±0.2 dB/cm, respectively) were measured in synthetic porous rocks with aligned, penny-shaped fractures using the laboratory ultrasonic pulse-echo method. Shear-wave splitting was observed by rotating the S-wave transducer and noting the maximum and minimum velocities relative to the fracture direction. A block of synthetic porous rock of fracture density 0.0201 ± 0.0068 and fracture size 3.6 ± 0.38 mm (measured from image analysis of X-ray CT scans) was sub-sampled into three 20–30 mm long, 50 mm diameter core plugs oriented at 0°, 45° and 90° to the fracture normal (transversely isotropic symmetry axis). Full waveform data were collected over the frequency range 500–1000 kHz for both water and glycerin saturated cores to observe the effect of pore fluid viscosity at 1 cP and 100 cP, respectively. The shear-wave splitting observed in the 90° core was 2.15 ± 0.02% for water saturated and 2.39 ± 0.02% for glycerin saturated, in agreement with the theory that suggests that the percentage splitting should be 100 times the fracture density and independent of the saturating fluid. In the 45° core, by contrast, splitting was 0.00 ± 0.02% for water saturation and −0.77 ± 0.02% for glycerin saturation. This dependence on fracture orientation and pore fluid viscosity is consistent with the poro-visco-elastic theory for aligned, meso-scale fractures in porous rocks. The results suggest the possible use of shear- or converted-wave data to discriminate between fluids on the basis of viscosity variations.

A matching pursuit method for approximating overlapping ultrasonic echoes

Ultrasonic pulse-echo methods have been used extensively in measuring the thickness of layered structures as well as those of thin adhesive interface layers. When acoustically measuring thin layers, the resulting echoes from two successive interfaces overlap in time, limiting the minimum thickness that can be resolved using conventional pulse-echo techniques. In this paper, we propose a method, named support matching pursuit (SMP), for resolving the individual echoes. The method is based on the concept of sparse signal approximation in an overcomplete dictionary composed of Gabor atoms (elementary functions). Although the dictionary enables highly flexible approximations, it is also overcomplete, which implies that the approximation is not unique. We propose a method for approximation in which each ultrasonic echo is principally represented by a single atom and therefore has a physical interpretation. SMP operates similarly to the sparse matching pursuit (MP) method. It iteratively improves the approximation by adding, at each iteration, a single atom to the solution set. However, our atom selection criterion utilizes the time localization nature of ultrasonic echoes, which causes portions of a multi-echo ultrasonic signal to be composed mainly from a single echo. This leads to accurate approximations in which each echo is characterized by a set of physical parameters that represent the composing ultrasonic echoes. In the current research we compare SMP to other sparse approximation methods such as MP and basis pursuit (BP). We perform simulations and experiments on adhesively bonded structures which clearly demonstrate the superior performance of the SMP method over the MP and BP methods.

Elastic constants in tetragonal hen egg-white lysozyme crystals containing large amount of water

Transverse sound velocity of cross-linked tetragonal hen egg-white (HEW) lysozyme crystals containing large amount of water in the crystal was measured using ultrasonic pulse-echo method. All elastic constants of cross-linked crystals were observed to be C11=C22=5.50 GPa, C12=4.33 GPa, C13=C23=3.94 GPa, C33=5.22 GPa, C44=C55=0.68 GPa, and C66=0.84 GPa, respectively. We found that the elastic constants of the cross-linked crystals are identical to those of the intrinsic ones without cross-linking. Moreover, we found that tetragonal HEW lysozyme crystals that enclose large amount of water show decreased elastic constants (softening). In particular, the shear elastic constants C44=C55 and C66 showed more softening effect comparing with other elastic components.

820 圧電フィルムを用いた超音波による欠陥検出・同定および構造ヘルスモニタリング手法(GS-3 計測・検査(2))

820 圧電フィルムを用いた超音波による欠陥検出・同定および構造ヘルスモニタリング手法(GS-3 計測・検査(2))

817 圧電フィルムを用いた超音波による欠陥検出・同定および構造ヘルスモニタリング手法(OS8.逆問題解析手法の開発と最新応用(4),オーガナイズドセッション)

817 圧電フィルムを用いた超音波による欠陥検出・同定および構造ヘルスモニタリング手法(OS8.逆問題解析手法の開発と最新応用(4),オーガナイズドセッション)

Fuel Regression Rate Behavior of CAMUI Hybrid Rocket

A series of static firing tests was conducted to investigate the fuel regression characteristics of a Cascaded Multistage Impinging-jet (CAMUI) type hybrid rocket motor. A CAMUI type hybrid rocket uses the combination of liquid oxygen and a fuel grain made of polyethylene as a propellant. The collision distance divided by the port diameter, H/D, was varied to investigate the effect of the grain geometry on the fuel regression rate. As a result, the H/D geometry has little effect on the regression rate near the stagnation point, where the heat transfer coefficient is high. On the contrary, the fuel regression rate decreases near the circumference of the forward-end face and the backward-end face of fuel blocks. Besides the experimental approaches, a method of computational fluid dynamics clarified the heat transfer distribution on the grain surface with various H/D geometries. The calculation shows the decrease of the flow velocity due to the increase of H/D on the area where the fuel regression rate decreases with the increase of H/D. To estimate the exact fuel consumption, which is necessary to design a fuel grain, real-time measurement by an ultrasonic pulse-echo method was performed.

Mechanical properties at sub-microscale and macroscale of polycrystalline uranium mononitride

The indentation hardness, Vickers hardness, fracture toughness, and Young’s modulus of polycrystalline uranium mononitride (UN) at sub-microscale and macroscale were evaluated by an indentation test, Vickers hardness test, and the ultrasonic pulse echo method. The Young modulus and Vickers hardness were in good agreement with the literature values. The fracture toughness of UN was about three times that of UO 2. In addition, we revealed the indentation size effect on the indentation hardness of UN.