Leonard J. Bond

An experimental study on the characteristics of wind-driven surface water film flows by using a multi-transducer ultrasonic pulse-echo technique

An experimental study was conducted to investigate the characteristics of surface water film flows driven by boundary layer winds over a test plate in order to elucidate the underlying physics pertinent to dynamic water runback processes over ice accreting surfaces of aircraft wings. A multi-transducer ultrasonic pulse-echo (MTUPE) technique was developed and applied to achieve non-intrusive measurements of water film thickness as a function of time and space to quantify the transient behaviors of wind-driven surface water film flows. The effects of key controlling parameters, including freestream velocity of the airflow and flow rate of the water film, on the dynamics of the surface water runback process were examined in great details based on the quantitative MTUPE measurements. While the thickness of the wind-driven surface water film was found to decrease rapidly with the increasing airflow velocity, various surface wave structures were also found to be generated at the air/water interface as the surf...

Survey of advanced nuclear technologies for potential applications of sonoprocessing

Ultrasonics has been used in many industrial applications for both sensing at low power and processing at higher power. Generally, the high power applications fall within the categories of liquid stream degassing, impurity separation, and sonochemical enhancement of chemical processes. Examples of such industrial applications include metal production, food processing, chemical production, and pharmaceutical production. There are many nuclear process streams that have similar physical and chemical processes to those applications listed above. These nuclear processes could potentially benefit from the use of high-power ultrasonics. There are also potential benefits to applying these techniques in advanced nuclear fuel cycle processes, and these benefits have not been fully investigated. Currently the dominant use of ultrasonic technology in the nuclear industry has been using low power ultrasonics for non-destructive testing/evaluation (NDT/NDE), where it is primarily used for inspections and for characterizing material degradation. Because there has been very little consideration given to how sonoprocessing can potentially improve efficiency and add value to important process streams throughout the nuclear fuel cycle, there are numerous opportunities for improvement in current and future nuclear technologies. In this paper, the relevant fundamental theory underlying sonoprocessing is highlighted, and some potential applications to advanced nuclear technologies throughout the nuclear fuel cycle are discussed.

Prognostics health management and life beyond 60 for nuclear power plants

There is growing interest in longer-term operation of the current US nuclear power plant (NPP) fleet. This paper presents an overview of prognostic health management (PHM) technologies that could play a role in the safe and effective operation of nuclear power plants during extended life. A case study in prognostics for materials degradation assessment, using laboratory-scale measurements, is briefly discussed, and technical gaps that need to be addressed prior to PHM system deployment for nuclear power life extension are presented.

Nondestructive characterization of pipeline materials

There is a growing need to quantitatively and nondestructively evaluate the strength and toughness properties of pipeline steels, particularly in aging pipeline infrastructure. These strength and toughness properties, namely yield strength, tensile strength, transition temperature, and toughness, are essential for determining the safe operating pressure of the pipelines. For some older pipelines crucial information can be unknown, which makes determining the pressure rating difficult. Current inspection techniques address some of these issues, but they are not comprehensive. This paper will briefly discuss current inspection techniques and relevant literature for relating nondestructive measurements to key strength and toughness properties. A project is in progress to provide new in-trench tools that will give strength properties without the need for sample removal and destructive testing. Preliminary experimental ultrasonic methods and measurements will be presented, including velocity, attenuation, and ...

Resonance analysis of a high temperature piezoelectric disc for sensitivity characterization

&NA; Ultrasonic transducers for high temperature (200 °C+) applications are a key enabling technology for advanced nuclear power systems and in a range of chemical and petro‐chemical industries. Design, fabrication and optimization of such transducers using piezoelectric materials remains a challenge. In this work, experimental data‐based analysis is performed to investigate the fundamental causal factors for the resonance characteristics of a piezoelectric disc at elevated temperatures. The effect of all ten temperature‐dependent piezoelectric constants (&egr;33, &egr;11, d33, d31, d15, s11, s12, s13, s33, s44) is studied numerically on both the radial and thickness mode resonances of a piezoelectric disc. A sensitivity index is defined to quantify the effect of each of the temperature‐dependent coefficients on the resonance modes of the modified lead zirconium titanate disc. The temperature dependence of s33 showed highest sensitivity towards the thickness resonance mode followed by &egr;33, s11, s13, s12, d31, d33, s44, &egr;11, and d15 in the decreasing order of the sensitivity index. For radial resonance modes, the temperature dependence of &egr;33 showed highest sensitivity index followed by s11, s12 and d31 coefficient. This numerical study demonstrates that the magnitude of d33 is not the sole factor that affects the resonance characteristics of the piezoelectric disc at high temperatures. It appears that there exists a complex interplay between various temperature dependent piezoelectric coefficients that causes reduction in the thickness mode resonance frequencies which is found to be agreement in with the experimental data at an elevated temperature. HighlightsThe effect of all ten temperature‐dependent material coefficients is investigated numerically on the resonance modes of a piezoelectric (PZT‐5A) disc.The temperature dependent variation in s33 showed highest sensitivity towards the thickness resonance mode followed by &egr;33, s11, s13, s12, d31, d33, s44, &egr;11, and d15 in the decreasing order of the sensitivity index.For radial resonance modes, the temperature dependence of &egr;33 showed highest sensitivity index followed by s11, s12 and d31 coefficient.A complex interplay between various temperature‐dependent piezoelectric coefficients causes the reduction of thickness mode resonance frequencies which is found to be in agreement with the experimental work.Proposed methodology based on the temperature dependent experimental data could potentially be used to estimate the sensitivity of piezoelectric based ultrasonic transducers at high temperatures.

Structural health monitoring ultrasonic thickness measurement accuracy and reliability of various time-of-flight calculation methods

The accuracy, precision, and reliability of ultrasonic thickness structural health monitoring systems are discussed in-cluding the influence of systematic and environmental factors. To quantify some of these factors, a compression wave ultrasonic thickness structural health monitoring experiment is conducted on a flat calibration block at ambient temperature with forty four thin-film sol-gel transducers and various time-of-flight thickness calculation methods. As an initial calibration, the voltage response signals from each sensor are used to determine the common material velocity as well as the signal offset unique to each calculation method. Next, the measurement precision of the thickness error of each method is determined with a proposed weighted censored relative maximum likelihood analysis technique incorporating the propagation of asymmetric measurement uncertainty. The results are presented as upper and lower confidence limits analogous to the a90/95 terminology used in industry recognized Probab...

Ultrasonic thickness structural health monitoring photoelastic visualization and measurement accuracy for internal pipe corrosion

Oil refinery production of fuels is becoming more challenging as a result of the changing world supply of crude oil towards properties of higher density, higher sulfur concentration, and higher acidity. One such production challenge is an increased risk of naphthenic acid corrosion that can result in various surface degradation profiles of uniform corrosion, non-uniform corrosion, and localized pitting in piping systems at temperatures between 150°C and 400°C. The irregular internal surface topology and high external surface temperature leads to a challenging in-service monitoring application for accurate pipe wall thickness measurements. Improved measurement technology is needed to continuously profile the local minimum thickness points of a non-uniformly corroding surface. The measurement accuracy and precision must be sufficient to provide a better understanding of the integrity risk associated with refining crude oils of higher acid concentration. This paper discusses potential technologies for measuring localized internal corrosion in high temperature steel piping and describes the approach under investigation to apply flexible ultrasonic thin-film piezoelectric transducer arrays fabricated by the sol-gel manufacturing process. Next, the elastic wave beam profile of a sol-gel transducer is characterized via photoelastic visualization. Finally, the variables that impact measurement accuracy and precision are discussed and a maximum likelihood statistical method is presented and demonstrated to quantify the measurement accuracy and precision of various time-of-flight thickness calculation methods in an ideal environment. The statistical method results in confidence values analogous to the a90 and a90/95 terminology used in Probability-of-Detection (POD) assessments.

Structural health monitoring of localized internal corrosion in high temperature piping for oil industry

Crude oil is becoming more corrosive with higher sulfur concentration, chloride concentration, and acidity. The increasing presence of naphthenic acids in oils with various environmental conditions at temperatures between 150°C and 400°C can lead to different internal degradation morphologies in refineries that are uniform, non-uniform, or localized pitting. Improved corrosion measurement technology is needed to better quantify the integrity risk associated with refining crude oils of higher acid concentration. This paper first reports a consolidated review of corrosion inspection technology to establish the foundation for structural health monitoring of localized internal corrosion in high temperature piping. An approach under investigation is to employ flexible ultrasonic thin-film piezoelectric transducer arrays fabricated by the sol-gel manufacturing process for monitoring localized internal corrosion at temperatures up to 400°C. A statistical analysis of sol-gel transducer measurement accuracy using ...

Acoustoelastic Lamb wave analysis in thin plates

Fabrication processes, such as, shot peening, bending, and rolling can induce residual stresses in metals that will impact product performance and cause phenomena such as cracking and corrosion. To better manage residual stress tools are needed to map their distribution. Ultrasonic methods can be used as a good tool for residual stress detection, and this approach is non-destructive and costs are modest. Methods which utilize longitudinal critically refracted (LCR) waves are receiving increased attention and it can be used on thick material. However, there have only been a limited number of studies which consider the acoustoelastic effect for thin plate materials which generate Lamb waves. This paper reports a study in which a numerical model is used to investigate the Lamb wave dispersion curves under loading that induce stresses. The effects of stress on various Lamb modes are discussed and those which appear to be most sensitive are identified. It is found that when the stresss direction is normal to the direction of wave propagation in a 1 mm thick aluminum plate the A0 mode is the most sensitive to the applied stress.

A FEASIBILITY STUDY TO IDENTIFY ICE TYPES BY MEASURING ATTENUATION OF ULTRASONIC WAVES FOR AIRCRAFT ICING DETECTION

Aircraft icing has been recognized as the most significant weather hazard that impacts aviation safety. A thin sheet of ice on lifting or control surfaces of an aircraft can adversely affect its flight performance by increasing drag and decreasing lift and thrust. The uncontrolled shedding of ice built up on surfaces may severely damage critical components. The occurrence of ice accretion is also a big challenge in terms of economic impact. The presence of ice can not only cause flight delays, but also reduce flight profits by increasing fuel consumptions and additional cost for de-icing operations. A better understanding of the physical mechanisms of water movement and the ice formation process on aircraft surfaces is very important and critical in ensuring safe and efficient operation of aircraft in cold weather. Generally there are two types of ice that can be deposited during flight: glaze ice and rime ice, which occur is dependent on weather conditions. Glaze ice is formed with high liquid water content (LWC) and large droplet size at temperatures just below the freezing point, and it has a smooth, clear and dense appearance. Rime ice forms with lower LWC and smaller droplet size at temperatures around or below −12 C°. It is a mixture of tiny ice particles, containing many micro bubbles and cracks, and it has a white rough appearance. These two types of ice may have significantly different effects on flight performance. However, most of the current de-icing approaches and practices do not consider this and operators potentially perform a lot of unnecessary actions. In this study, attenuation measurement of ultrasonic waves is performed to investigate the feasibility of characterization of ice types. Analysis investigates frequency dependent attenuation properties that are potentially closely related to ice acoustic properties and hence the micro-structure.Copyright