A device for the measurement of ultrasonic velocity and attenuation in solid materials under different thermal conditions (original) (raw)
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Temperature Gradients and Materials Properties Measurements using Ultrasonic Guided Waves
2014
A novel technique for the measurement of Elastic Moduli of materials as well as measurement of temperature gradients using ultrasonic waveguides is described here. The range of temperature measurement was from room temperature to maximum utility temperature of waveguides or maximum measurable value of thermocouple temperature, typically beyond 1000°C. In this work, thermocouple wires have been used as a wave guide subsequently time of flight and temperature data was collected from laboratory experiments from 45°C to 1100°C. The changes in sound speed can be determined through the time of flight variations of the wave that also depends on the particular geometry of waveguide.
Proceedings of the ICA congress, 2019
In special cases of angle beam ultrasonic measurement-e.g. defect detection in hot solids as well as flow measurement of liquid gases or energy storage mediums [1]-the applied transducer has to withstand extreme temperatures. Since the irradiation angle into the specific material is determined not only by wedge design, but also by the speed of sound in both the wedge material and the tested object, the developer must take into account the speed of the wave propagation in a wedge material over the whole temperature range of transducers application. In this study we investigate the temperature dependence of the speed of longitudinal wave propagation in 10 different materials in the range from-200 °C to 400 °C. The investigated materials belong to different material classes (ceramics, glass, as well as ferrous and non-ferrous metals) and are all temperature-resistant up to at least 600 °C, and therefore applicable as wedge materials in an ultrasonic transducer for use at extreme temperatures.
On the measurement of frequency-dependent ultrasonic attenuation in strongly heterogeneous materials
Ultrasonics, 2010
This paper deals with the measurement of frequency-dependent ultrasonic attenuation in strongly heterogeneous materials, such as cementitious materials. To improve the measurement of this parameter on this kind of materials, a linear swept-frequency signal is used to drive an emitter transducer to conduct a through-transmission inspection in immersion. To filter out undesirable frequency content, time-frequency filtering and detection process are performed. The use of this method has been compared with two excitation techniques, the broadband and the narrowband pulses. The results obtained using the swept-frequency excitation together with the time-frequency filtering, allows the determination of the attenuation curves with high accuracy over a wide frequency range without the need for complicated equipment, and improves the effective bandwidth by using a unique pair of transducers.
Materials Science and Engineering: A, 1989
A very precise method for measurements of the variation in the velocity of sound in solids" in the 500 MHz frequency range is presented. The method is based on a pulse interference method and allows the observation of relative velocity changes of the order of 10 7 or better. The availability of this method made it possible to detect the "glassy" behaviour of the low temperature velocity of sound in electron-irradiated quartz and in neutron-irradiated quartz for low doses and to fit the results to the tunnelling model. The fittings give more convincing evidence that the tunnelling states in electron-irradiated quartz are of similar nature to those in neutron-irradiated quartz. The density of states, however, is very much smaller in electron-irradiated quartz than in neutron-irradiated quartz for a similar dose.
Measurement of Elastic Properties of Materials by the Ultrasonic Through-Transmission Technique
2011
The elastic mechanical behavior of elastic materials is modeled by a pair of independent constants (Young’s modulus and Poisson’s coefficient). A precise measurement for both constants is necessary in some applications, such as the quality control of mechanical elements and standard materials used for the calibration of some equipment. Ultrasonic techniques have been used because wave velocity depends on the elastic properties of the propagation medium. The ultrasonic test shows better repeatability and accuracy than the tensile and indentation test. In this work, the theoretical and experimental aspects related to the ultrasonic through-transmission technique for the characterization of elastic solids is presented. Furthermore, an amorphous material and some polycrystalline materials were tested. Results have shown an excellent repeatability and numerical errors that are less than 3% in high-purity samples.
Appl. Sci., 2020
In this paper, ultrasonic attenuation of engineering materials is evaluated comprehensively, covering metals, ceramics, polymers, fiber-reinforced composites, wood, and rocks. After verifying two reliable experimental methods, 336 measurements are conducted and their results are tabulated. Attenuation behavior is determined over broadband spectra, extending up to 15 MHz in low attenuating materials. The attenuation spectra are characterized in combination with four power law terms, with many showing linear frequency dependence, with or without Rayleigh scattering. Dislocation damping effects are re-evaluated and a new mechanism is proposed to explain some of the linear frequency dependencies. Additionally, quadratic and cubic dependencies due to Datta-Kinra scattering and Biwa scattering, respectively, are used for some materials to construct model relations. From many test results, some previously hidden behaviors emerged upon data evaluation. Effects of cold working, tempering, and annealing are complex and sometimes contradictory. Comparison to available literature was attempted for some, but most often prior data were unavailable. This collection of new attenuation data will be of value in materials selection and in designing structural health monitoring and non-destructive inspection protocols.
Characterization of Material Properties by Ultrasonics
Non-destructive testing techniques are most commonly employed for detection and characterization of flaws in the component. Apart from flaw characteristics, another parameter which is equally important to assess the structural integrity of engineering components is the material property. Nondestructive testing techniques offer several advantages over the conventional coupon-based techniques. Ultrasonic Testing is one of the widely used NDT techniques for material characterization. In the past few decades, researchers all over the world have carried out extensive study to characterize, both microstructural and mechanical properties of materials by ultrasonic testing. This paper highlights the ultrasonic testing parameters useful for material characterization studies and also investigations carried out in various laboratories including authors' laboratory on characterization of microstructural and mechanical properties of materials, qualification of processing treatments during fabrication and assessment of damage during service due to various degradation mechanisms.
Investigation of Stress and Temperature Effect on the Longitudinal Ultrasonic Waves in Polymers
Research in Nondestructive Evaluation, 2014
This work aims at establishing the effect of stress and temperature on the velocity of ultrasonic longitudinal waves in typical engineering polymers, and evaluating the potential of ultrasonic stress measurement in the evaluation of residual stresses in polymer parts. In order to estimate the effect of material morphology, two amorphous and two semicrystalline polymers have been considered. A series of tests are implemented, to determine the acoustoelastic constants and temperature constant of materials, by using the designed transducer fixtures for in situ measurement of longitudinal wave velocity. As expected, the velocity changes linearly with stress and temperature, and the temperature effect is as important as the acoustoelastic effect. It shows that this kind of nondestructive method is a valuable quantitative tool to estimate the residual stress in polymer products, but the material temperature influence must be considered during the estimation.
2010
The aim of this work is the evaluation of a device for the ultrasonic propagation speed measurement in biological tissues as well as its possible error sources during signal acquisition process. The proposed measurement system basically consists of an immersion transceiver, which was excited by a home-made pulser. The transducer radiates the interrogated material and a needles arrangement inserted in it. This arrangement generates a well defined echo pair. These echoes combine with the echoes generated in the characterized medium after they have been amplified. In the case of the measurement of the temperature dependence of ultrasonic propagation speed, the measurement system must be submerged inside a thermostatic bath which is capable of regulating the temperature within a 0.1°C resolution. The measurement of the distance between the needles that work as reflectors, and the vibrations caused by the hydraulic pump could generate artifacts in the acquired ultrasonic signals. These variations would induce error in the ultrasonic propagation speed measurements. A method to measure the distance between the reflector needles is proposed, and an evaluation of the effects of the vibrations as well as the advantages of using a fixed distance between the reflector needles is presented. The obtained results show that the thermostatic bath operation has effect on the ultrasonic signals; however, it could be neglected due to its minimal contribution in the propagation speed measurement. It is also proved that the needles arrangement is a good option to measure the propagation speed showing values near to the reported in degasified bidistilled water.
Physics Procedia, 2015
Some technical aspects of two Spanish cooperation projects, funded by DPI and Innpacto Programs of the R&D National Plan, are discussed. The objective is to analyze the common belief about than the ultrasonic testing in MHz range is not a tool utilizable to detect internal flaws in highly attenuating pieces made of coarse-grained steel. In fact high-strength steels, used in some safe industrial infrastructures of energy & transport sectors, are difficult to be inspected using the conventional "state of the art" in ultrasonic technology, due to their internal microstructures are very attenuating and coarse-grained. It is studied if this inspection difficulty could be overcome by finding intense interrogating pulses and advanced signal processing of the acquired echoes. A possible solution would depend on drastically improving signal-to-noise-ratios, by applying new advances on: ultrasonic transduction, HV electronics for intense pulsed driving of the testing probes, and an "ad-hoc" digital processing or focusing of the received noisy signals, in function of each material to be inspected. To attain this challenging aim on robust steel pieces would open the possibility of obtaining improvements in inspecting critical industrial components made of highly attenuating & dispersive materials, as new composites in aeronautic and motorway bridges, or new metallic alloys in nuclear area, where additional testing limitations often appear.