Results 1 - 10 of 979
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[en] This paper presents results of a TFM implementation for Full Matrix Capture acquisitions in CIVA, proposed as a post-processing tool for accurate analysis. This implementation has been made on GPU architecture with OpenCL to minimize the processing time and offer computational device flexibility (GPU/CPU). Examples on immersion configurations on isotropic 2D CAD specimen with planar extrusion are proposed to illustrate the performances. Reconstructions on 2D or 3D areas of direct echoes with mode conversion are allowed. Probe scanning can also be taken into account. Reconstruction results and a benchmark explaining the speedup are presented. Further improvements are also reviewed. (authors)
[en] Phasor XS can be used for piping weld inspection in any facilities that use EPRI procedures (example: nuclear power plant in Usa, Japan, ...). Whole pipe range is inspected with 5 probes and 6 wedges: 4 1-dimensional probe for sound wave scanning (different frequency, different apertures); 1 dual matrix probe for LW scanning; there are 3 types of wedges optimized for weld inspection. Weld is scanned in 'Raster Scan', maximum range from 35 up to 80 degrees. Probe selection is defined in the procedure according to pipe diameter, pipe thickness and type of access (single or dual side). We have to note that datasets for dual matrix probe are provided with the procedure because this kind of probe cannot be programmed inside Phasor XS
[en] Methods based on propagation of stress wave phenomena indicate particularly useful in diagnosis of non-metallic materials. The aim of this research is to demonstrate that ultrasonic measurement can produce satisfactory results in predicting certain mechanical properties of standing Aquilaria malaccensis tree. The mechanical information is very important to diagnose the condition inside the trunk. The experiment has been conducted on agarwood samples using a pulse compression ultrasonic system. The apparatus equipped with exponential horn 54 kHz piezoelectric normal probe. Through transmission method of longitudinal ultrasonic wave has been used throughout this experiment to measure velocity of ultrasonic signal through the sample. The result showed that the ultrasonic technique can be used in diagnosing of wood-based samples. (author)
[en] The present study investigated the influence of thick cortical endplates on the ultrasonic properties of trabecular bone in a femur with a high fracture risk. Twelve trabecular bone samples were prepared from bovine femurs, and acrylic plates with thicknesses of 1.25, 1.80, and 2.75 mm were manufactured to simulate the cortical endplates using acrylic with a density and a sound speed similar to cortical bone. Although the thickness of the acrylic plates attached to the two sides of the trabecular bone increased, high correlations were observed between the speed of sound and the apparent bone density of the trabecular bone, with Pearson's correlation coefficients of 0.80-0.86. High correlations were also observed between the attenuation coefficient at 0.5 mm and the apparent bone density of the trabecular bone, with Pearson's correlation coefficients of 0.84-0.91. These results suggest that the speed of sound and attenuation coefficient at a specific frequency measured in a femur with relatively thick cortical endplates compared to the calcaneus could be used as indices for predicting the bone mineral density of the femur.
[en] In long range ultrasonic testing, a phased array probe composed of multiple identical transducers with an uniform interval of one quarter wavelength is usually used for the transmission or reception directivity control. This paper shows that the propagation directions of individual echoes can be identified in real time by displaying the inputs of a process for summing the constitution reception signals after compensating the phase difference due to the transducer interval, together with the output of the process. A constructive interference of the constitution echoes indicates a forward direction echo propagating along an intended direction while a destructive interference implies a reverse direction echo propagating along the direction opposite to the intended one
[en] The cold-worked Zr-2.5%Nb alloy is used as material for the pressure tubes of CANDU nuclear reactors. It has developed a strong texture due to the limited slip system during extrusion process, leading to anisotropic properties. The material properties are strongly dependent on the orientation distributions of grains. For this reasons result a directional anisotropy of elastic coefficients. During the service life in reactor, diffusion of hydrogen and/or deuterium in the pressure tubes wall may occur. Zirconium alloys have a low solubility for hydrogen. Thus, when solubility limits are exceeded, a brittle second phase (hydrides) appear. The hydrides, even in small concentrations, can potentially have a dramatic effect on the structural integrity of zirconium alloys nuclear components. To characterize the degree of anisotropy and the hydrogen influence it is necessary to determine the anisotropic elastic modulus on the main directions (axial, circumferential and radial) of the tube samples. In the present paper, the most usual elastic modulus on a given direction (axial, circumferential and radial) of the tub (Zr-2.5%Nb alloy) were investigated using non-destructive method based on measurements of ultrasonic velocity. Thus, both longitudinal VL and transversal VT phase velocities have been experimentally determined for each direction. (authors)
[en] The purpose of this article is to provide guidance on settings and methods, in particular the careful use of gating, to ensure accuracy of thickness testing on corroded steel and other metallic components. Specific applications include boiler tubes, tank floors, piping and vessels where the testing is performed from the OD or top surfaces, inspecting for metal loss due to corrosion on the opposite side. (author)
[en] An ultrasonic synthetic aperture focusing technique (SAFT) using a root mean square (RMS) velocity model is proposed for pulse-echo immersion testing to improve the computational efficiency. Considering the immersion ultrasonic testing of a steel block as an example, three kinds of imaging were studied (B-Scan, SAFT imaging based on ray tracing technology and RMS velocity). The experimental results show that two kinds of SAFT imaging have almost the same imaging performance, while the efficiency of RMS velocity SAFT imaging is almost 25 times greater than the SAFT based on Snell's law
[en] Like the phase array based ultrasonic system, complicated electronics has been used for real time signal processing in the magnetostrictive long-range ultrasonic testing(LRUT) system. This study shows that the software approach including the phase compensation, noise filtering and waveform transformation takes advantage rather than the previous hardware approach. Furthermore, it is possible for the software approach to be able more flexible and efficient realtime signal processing. These results will contribute to a cost-effective LRUT system and analysis of the inspection data.
[en] Nonlinearity parameter is an inherent property of materials measuring fundamental acoustic amplitude(A1) and second harmonic amplitude(A2). However, measurement of A1 and A2 has complex calibration procedure, many researchers prefer to measure relative nonlinearity parameter rather than absolute nonlinearity parameter. But, relative nonlinearity parameter is only detect materials degradation with various degradation samples, it is limited application in determining third order elastic constants of materials. Therefore, in this study, the piezoelectric detection method is adopted to measure absolute nonlinearity parameter due to experimental simplicity compare to capacitive detector. Linearity of measurement system is verified by A12usA2 plot, and we measured ultrasonic nonlinearity parameters of fused silica and Al2024-T4