Ultrasonic Thickness Measurement Research Articles

A method to determine the uncertainties of solid particle erosion measurements utilizing machine learning techniques

The ability to predict solid particle erosion is a vital task for the integrity management of pipelines carrying solid particles in many industries. Usually, the accuracy of predicted values is assessed by comparing them with the measured erosion of some cases where data is available. Thus, defining the uncertainties of the experimental data of erosion is crucial to evaluate the reliability of the predictions of solid particle erosion and consequently, the decisions made based on these predictions. The databases gathered by many investigators that include erosion data of various test cases have been considered for this uncertainty investigation. These cases include erosion rate data collected using the ultrasonic thickness measurement technique for gas-sand flows in 0.0508, 0.0762, and 0.1016-m elbow geometries with various particle sizes (75,150,300,550 μm) and air velocities vary in the range between 11 up to 202 m per seconds. This study aims to develop a framework for defining the uncertainties of erosion experiments. For this purpose, first, the uncertainties of repeated experiments were estimated and then analytical analysis was used to generalize these results to cases where repeated results were unavailable. Based on this idea, a correlation between erosion and the most effective parameters was developed. Then, machine learning algorithms were used to determine a correlation between the erosion rate and chosen parameters including material hardness, pipe size, particle size, and flow velocity. The framework of the current model/method is based on the combined results of analytical analysis and machine learning procedure, and the estimated uncertainties are presented by lower and upper bounds curves of erosion data.

Environmental aspects of metal corrosion at oil and gas chemical enterprises

Metal corrosion of technological equipment not only has a significant impact on industry, but also has serious consequences for the environment, being one of the causes of environmental problems. The object of research in this paper is the issue of corrosion damage to the metal of technological equipment, types of corrosion and corrosion damage, and methods of protection against corrosion. On the example of a shell and tube heat exchanger with the help of nondestructive methods of control (external and internal inspection, ultrasonic thickness measurement) the research of corrosion rate of its main elements has been carried out. According to the results of researches the calculation of corrosion rate of the main elements of the heat exchanger was carried out. The corrosion rate for the heat exchanger shell was found to be 0.37 mm/year, which exceeds the value of 0.1 mm/year, which is accepted in the design of this heat exchanger. The obtained results allowed to identify the most vulnerable places of the research object and to choose the most effective ways to protect the base metal of the heat exchanger from corrosion.

Application of Pulse Compression Technology in Electromagnetic Ultrasonic Thickness Measurement of High-Temperature Continuous Casting

Application of Pulse Compression Technology in Electromagnetic Ultrasonic Thickness Measurement of High-Temperature Continuous Casting

Dry Coupled Ultrasonic Non-Destructive Evaluation Using an Over-Actuated Unmanned Aerial Vehicle

Unmanned aerial vehicles (UAVs) are seeing increasing adoption to automated remote and in situ inspection of industrial assets, removing the need for hazardous manned access. Aerial manipulator architectures supporting pose-decoupled exertion of force and torque would further enable UAV deployment of contact-based transducers for sub-surface structural health assessment. Herein, for the first time, we introduce an over-actuated multirotor deploying a dry-coupled ultrasonic wheel probe as a novel means of wall thickness mapping. Using bi-axial tilting propellers in a unique tricopter layout, this system performs direct thrust vectoring for efficient omnidirectional flight and application of interaction forces. In laboratory testing, we demonstrate stable and repeatable probe deployment in a variety of representative asset inspection operations. We obtain a mean absolute error (MAE) in measured thickness of under 0.10 mm when measuring an aluminum sample with varying wall thickness. This is maintained over repeated exit and reentry of surface contact and when the sample is mounted vertically or on the underside of a 45° overhang. Furthermore, when rolling the probe dynamically across the sample surface in an area scanning modality, an MAE in wall thickness below 0.28 mm is recorded. Multi-modal operational confidence bounds of the system are thereby quantitatively defined. Note to Practitioners—Motivation for this article stems from the desire to enhance the speed and level of insight into structural health currently offered through remote aerial inspection processes. We approach this by integration of a thrust vectoring multirotor platform with a dry-coupling wheel probe for aerial ultrasonic thickness measurement. This system reliably presses the probe into the target surface and obtains point measurements across various surface orientations without a stabilizing frame. This broadens applicability and permits novel inspections where couplant gel would otherwise contaminate the surface and require manual cleaning. We profile thickness along a scanned linear section, a mode suited to corrosion mapping of large surface areas such as petrochemical storage tanks, pipework, or similar assets. We also make detailed consideration toward measurement accuracy, repeatability, and localization, an aspect commonly overlooked in literature. Future work to characterize variable friction effects currently limiting rolling scan speed and measurement coverage density may be beneficial. Quantitative study of the effectiveness of dry-couplant in the presence of any uncommon surface contaminants specific to a desired use-case is also advised.

Comparison of the Effectiveness of the Ultrasonic Method and Cone-Beam Computed Tomography Combined with Intraoral Scanning and Prosthetic-Driven Implant Planning Method in Determining the Gingival Phenotype in the Healthy Periodontium.

The aim of this study was to compare the effectiveness of two diagnostic methods: ultrasonic gingival thickness measurement (UGTM) and cone-beam computed tomography, intraoral scanning by computer-aided design technology with prosthetic-driven implant planning software (CBCT/CAD/PDIP) in determining the gingival phenotype (GP). Thirty periodontally healthy patients were examined. The ultrasonic device Pirop G® with a frequency of 20 MHz and CBCT/CAD/PDIP were used to measure gingival thickness at upper canines and incisors in three points localized midbuccally, namely free gingival thickness (FGT), supracrestal (SGT) and crestal (CGT). Probing depth (PD), clinical attachment level (CAL) and width of keratinized tissue (WKT) were measured using periodontal probe. Intra-examiner and inter-examiner agreement and agreement between methods were evaluated using Bland-Altman analyses. Comparing both methods in the determination of SGT (bias = 0.17 mm, SD = 0.25 mm, p < 0.000) and CGT (bias = −0.45 mm, SD = 0.32 mm, p < 0.000) 95.0% and 95.6% agreement were found, respectively, and in the FGT range only 93.3% (bias = −0.45 mm, SD = 0.32 mm, p < 0.000). The presence of positive correlations between WKT and SGT was shown. A positive correlation between SGT and WKT confirms the purpose of measuring these parameters for the evaluation of the GP. Both the ultrasonic method and cone-beam computed tomography combined with intraoral scanning and prosthetic-driven implant planning method were useful in determining gingival phenotype, however, the ultrasonic method was more accurate for measuring GT.

Specifics of diagnostics and investigation of material properties in pipes with planar defects

The paper presents findings of a study on planar defects formed on the inner surface of gas pipeline metal in the operation process. The diagnostic indicators of a defective section were determined and analyzed using the intelligent pigging data. A broad range of research was carried out, including visual and measuring control of the object, step-by-step ultrasonic thickness measurement, chemical analysis, optical and electron microscopy, microhardness measurement of defective and defect-free areas, static tensile and impact bending tests. The structure and morphology of defective and defect-free areas were considered. It was determined that the cause of the defects is contamination of the source material with gas pores and fluorspar residues. The defects of planar nature are formed during rolling and can be characterized as metal delamination. The maximum detected thickness of the inclusions was 1.0 mm, however, the main part was rolled to 10.0 μm. The key feature of defects is their location on various levels throughout the wall cross-sections, ranging from one to four detected layers or groups of rolled discontinuities. It is shown that such defects lead to a change in the strength properties of defective area, uneven distribution of loads and reduction in safety margin of the object.

Importance of Condition Assessment Programme by Ultrasonic Measurement

Paper gathers information on Condition Assessment Programme (CAP), which is implemented by classification societies to thoroughly assess condition of tankers and bulk carriers by inspection of engine and hull. It is voluntary programme, mostly participated by tankers and bulk carriers which are fifteen and more years old and today less present on the market. Special focus will be on ultrasonic measurement of thickness of ship´s plates which is most significant indicator on condition of older vessels. After all measuring is done, data is compared with classification society rules and condition of hull and machinery will be assessed. This kind of inspection provides owners of older ships proof that despite age their ships are equally capable of conducting sea voyage. The authors analyse the number of ship arrivals in the port of Rijeka to gain a better insight into their age. Furthermore, the authors advocate ultrasonic thickness measurement for the purpose of reducing hazards.

Collaborative detection and on-line monitoring of pipeline stress in oil and gas stations

The types of pipeline used in oil and gas stations is diverse, and it is difficult to comprehensively and accurately measure pipeline stress using a single detection method. Non-contact pipeline magnetic detection (NPMD), metal magnetic memory, ultrasonic stress measurement (USM) and ultrasonic thickness measurement (UTM)constitute a collaborative detection strategy for station pipelines. The pipeline magnetic abnormal evaluation parameter N is derived according to the sensor arrangement in NPMD devices. The magnetic field distribution based on different extraction heights is determined by the magnetic charge model and the experimental results, and a feature parameter E is constructed that can characterize the degree of stress concentration. The pipeline stress concentration points can be quickly determined in accordance with N and E. Reference stress values can be measured using USM and UTM. Monitoring is implemented at the stress concentration points, and the true stress values at the stress concentration points of the pipeline are established by combining the stress detection results. The collaborative detection method is applied to an oil and gas station, and two stress concentrations of 186.7 and 211.6 MPa are identified, respectively. The stress at the excavation pit is confirmed to be 196 MPa based on the monitoring data. Based on collaborative detection and on-line monitoring, fast and efficient collaborative detection and real-time mastering of station pipeline stress are achieved.

Ultrasonic measurement of oil film thickness in a four-layer structure for applications including sliding bearings with a thin coating

Owing to the non-destructive feature, ultrasonic techniques have been developed to measure the oil film thickness in sliding bearings. If a bearing has a thick coating, then the ultrasonic reflection from a four-layer structure consisting of pad-coating-oil-steel is equivalent to that of coating-oil-steel, where classical three-layered ultrasonic models can be applicable to estimate the thickness of oil film. However, in the case of thinly coated bearings, the measurement accuracy of existing models deteriorates due to signal overlapping. Despite two signal processing methods that have been attempted to isolate the desirable oil film echoes, the challenge remains when dealing with widely ranged oil film thickness. In contrast, this paper presents a unified ultrasonic model that enables accurate measurements of oil film thickness that is widely ranged in a thinly coated bearing. This model is mathematically derived from multi-layer continuum models with the oil thickness and the complex reflection coefficients correlated. It also takes into account two typical locations of the embedded transducer in the bearing. The viability of the proposed method is experimentally validated using a high-precision calibration rig, showing that the oil film that ranges from 6 μm to 97 μm can be accurately measured in the application to thinly coated (around 400 μm) bearings, where the measurement errors are not greater than 7.4%.

Erosion hot spots of drain valve under higher particle flow rates

Drain valves mounted onto the blow-off pipelines of natural gas gathering plants are often used to discharge deposited particles in separators. Particle flows (greater than 0.01 kg/s) always lead to inner and even outer leakage owing to erosion hot spots in the valve body and valve core. In this study, various approaches, including online particle monitoring experiments, ultrasonic wall thickness measurements, and flow control methods were used to investigate valve erosion hot spots in field experiments. Numerical simulations with a large-scale moving grid method were conducted to demonstrate the dynamic erosion in a compressible gas flow. The results reveal that the erosion hot spots continuously shifted to nearby areas during the surface evolution. The local erosion rate of the original erosion hot spots always exhibited a decreasing trend, while the erosion rates of the nearby hot zones exhibited an increasing–decreasing trend. The erosion rate of the erosion-deformed zones that suffered delayed particle impacts always exhibited an increasing trend. When the pressure increased from 0.5 MPa to 3.5 MPa, the erosion hot spots shifted to Point_B 3. The velocity contour considering the gas compressibility was also determined for this process, and the gas velocity spraying to the facing wall was successfully created. The Oka erosion model was combined with the moving grid method and validated as the most appropriate method for predicting erosion hot spots. As time evolved, the operational flow rate of a 10% valve opening at 46,080 s was equal to the flow rate of a 40% opening at 0 s. On the basis of this relationship, the entire failure process of the valve was accurately obtained using a semi-empirical method. Finally, two novel valve structures are proposed to create a strong erosion–absorbing effect and thereby weaken the erosion hot spot of the valve.

Pulsed eddy currents in ferromagnetic pipes with cladding in nuclear power plants

The steam and water piping in a nuclear power plant is generally covered with cladding on the outer wall of the pipes, thereby improving heat transfer efficiency. The current means of detection for ferromagnetic pipes mainly involve conventional ultrasound and ultrasonic guided waves. Prior to the detection, outer wall insulation of the pipes needs to be removed, resulting in an extended detection period and increased labor costs, which fails to meet the requirements of high-quality development of the nuclear power plant. The application of pulsed-eddy current technology in the nuclear power plant removes insulation and enables online screening without shutdown. The ability to identify defects under large lift-off is an important indicator for pulsed eddy current technology, which is of great significance for implementing pulsed eddy current in the nuclear power sector. In this paper, the Maxwell module in ANSYS is used for pipe modeling and simulation. A vertical detection coil is designed to simulate the detection capability of pulsed eddy current for flat bottom defects under large lift-off. Sample pipes from the nuclear power plant are selected for vertical pulsed eddy current testing (PECT). The PECT results are rechecked against ultrasonic thickness measurement to verify the PECT performance under the lift-off scenario and propose future development trends.

A precision grinding technology for zirconium alloy tubes based on ultrasonic wall thickness automatic measurement system

To ensure the safety and long-term performance of nuclear fuel cladding zirconium tubes, the wall thickness uniformity of each cross-section is strictly needed. Therefore, this paper developed an automatic ultrasonic wall thickness measurement system for detecting and precision grinding the nuclear zirconium tubes. The overall scheme, key mechanical structures, and design of the control system are determined considering the project background and measuring requirements. Then, a series of performance testing was performed from aspects of measuring accuracy, measuring efficiency, stability, and practicability. The results revealed that it could accurately obtain the wall thickness distribution with high accuracy and efficiency, and subsequently the precision grinding process by automatically generated deviation correcting procedures to achieve the requirement of the wall thickness uniformity and surface quality. The proposed new combination method of ultrasonic auto-measuring and precision grinding proposed in this work would have great significance for the development and application of nuclear reaction zirconium alloy containers.

A novel permeability perturbation testing method for delaminations in steel plates

ABSTRACT Delaminations have been detected based on the principle of ultrasonic thickness measurement. However, there are blind zones in the detection of surface delamination. Besides, the high-speed detection system is complicated. A novel permeability perturbation testing (PPT) method for the inspection of delaminations in ferromagnetic materials is proposed in this paper. When DC magnetisation is applied in the thickness direction of steel plate, the delamination in the plate will distort the internal magnetic field, leading to local permeability perturbation. This perturbation is transmitted to the surface layer of steel plate in the thickness direction. Using a differential-type eddy current transducer, internal delaminations are detected by measuring relative variation of surface permeability. The variation of permeability in the near surface of steel plate with the movement of delamination and the change of magnetisation state of the steel plate are obtained through finite element simulation. The feasibility of the above method is further verified through an experiment. This new method has the advantage in high-speed detection of delamination.

In-situ monitoring of membrane fouling migration and compression mechanism with improved ultraviolet technique in membrane bioreactors

An improved UV spectrum in-situ monitoring system was applied to explore the membrane fouling behavior in membrane bioreactors (MBRs). The changes in absorbance curve illustrated that the formation of a stubborn fouling layer includes the migration and compression of membrane surface foulants. The initial flux negatively correlates with the migration degree (unevenness) of membrane fouling, while fiber length is positively correlated. In further experiments, ultrasonic thickness measurement excludes fouling layer compression caused by spatial collapse under external force. Moisture content measurement tests demonstrated that the moisture content changed from 52% to 31% after fouling layer compression, which confirmed that the fouling layer compression is mainly caused by the “high pressure dehydration effect”. Finally, a membrane backwashing strategy based on fouling layer compression theory indicated that the backwashing process should be carried out at a stage where the accumulation of membrane fouling is constant but the fouling layer is not compressed.

Metallurgical investigation of boiler tube failure in a power plant

The boiler tube used in the power plant industry had failed prematurely after 11 years of service, which was used to supply steam at working temperature – 420 °C (approx) and working pressure of about ∼ 146 kg/cm2. The failed tube cut off the steam supply to the power plant industry and caused the plant to shut down for several days. So in this paper, the root cause failure of the boiler tube has been investigated. The tube was made from SA 210 Gr. C steel supplied in hardened and tempered conditions. However, certain defects in the manufacturing process and corrosion/erosion in the tube have initiated to thin the tube and resulted in failure of the tube. Due to these defects, the wall thickness was reduced by more than 20% of the nominal thickness. The microstructure analysis around the failure zone and away from the failure zone confirms the normal microstructure of ferrite and pearlite. Finally, it is recommended to use a defect-free tube and in case of severe erosion, ultrasonic wall thickness measurement may be carried out to check the reduction in thickness, so that the premature failure of the tube can be avoided in the near future.

Five-axis Ultrasonic Thickness Measurement of Hollow Blade Wall and Evaluation of Internal Chamber Section

Hollow blades play an important role in the aircraft engines. To ensure the manufacturing quality of the hollow blades, an ultrasonic inspection method for inspecting the internal chamber is proposed in this paper. The measured data is obtained by a five-axis Coordinate Measuring Machine with an ultrasonic probe. To fill the vacancy of data in high-curvature regions, an approximation curve is constructed according to the theoretical section line and the measured points. By adjusting the position of the theoretical clamber point and setting the adjustment direction, the non-uniform shrinkage of the ceramic core is simulated and the calculation amount is reduced. Filling points are obtained from the approximation curve and the internal chamber section is reconstructed by these points. The internal chamber of the hollow blade is evaluated from the two aspects of line profile and wall thickness. The experiments have verified the effectiveness of the proposed method.

Indoor accelerated controlled corrosion degradation test of small- and large-scale specimens

The work presented here is a part of a long-term project analysing the structural behaviour of ageing marine structures. An accelerated corrosion degradation set-up was developed to reproduce corroded marine structural specimens of different degrees of degradation, controlling various natural factors, i.e., temperature, oxygen content, salinity, and flow velocity. The nine stiffened plates of 1.2 m length and 30 small scale specimens made of mild steel of three different thicknesses have been corroded. The mean corrosion depth and rate have been controlled during the degradation process for all specimens. The corrosion degradation characteristics have been measured and analysed. In the case of small-scale specimens, microscope scanning, and for the stiffened plates, ultrasonic thickness measurements were performed. The obtained corrosion surfaces are highly non-uniform. During the corrosion degradation, a number of measurements were performed to satisfy a confidence level of 95% and an error of 10%. The developed corrosion degradation is compared with a real corrosion depth measurement of ship deck plates of ballast and cargo tanks, showing a very good similarity in the trend and the corrosion acceleration, concluding that the developed corrosion degradation controlled experimental set-up is efficient in reproducing marine structural specimens of different degree of degradation for further mechanical testing.

Analysis of pipe thickness reduction according to pH in FAC facility with In situ ultrasonic measurement real time monitoring

Flow accelerated corrosion (FAC) is a type of pipe corrosion in which the pipe thickness decreases depending on the fluid flow conditions. In nuclear power plants, FAC mainly occurs in the carbon steel pipes of a secondary system. However, because the temperature of a secondary system pipe is over 150 °C, in situ monitoring using a conventional ultrasonic non-destructive testing method is difficult. In our previous study, we developed a waveguide ultrasonic thickness measurement system. In this study, we applied a waveguide ultrasonic thickness measurement system to monitor the thinning of the pipe according to the change in pH.The Korea Atomic Energy Research Institute installed FAC-proof facilities, enabling the monitoring of internal fluid flow conditions, which were fixed for ~1000 h to analyze the effect of the pH. The measurement system operated without failure for ~3000 h and the pipe thickness was found to be reduced by ~10% at pH 9 compared to that at pH 7. The thickness of the pipe was measured using a microscope after the experiment, and the reliability of the system was confirmed with less than 1% error. This technology is expected to also be applicable to the thickness-reduction monitoring of other high-temperature materials.

Investigation of Online Corrosion Monitoring for Grounding Materials Based on Electromagnetic Ultrasonic Technology

Power grounding is a key aspectofensuringsafety in power facilities.However, the corrosion of grounding materials can cause accidentsduringpower facility operation. Therefore, monitoring the corrosion status of grounding materials can eliminate hidden risks in the grounding network and ensure safe poweroperation. In this paper, electromagnetic ultrasonic thickness measurement technology was used to develop an online corrosion monitoring system for grounding materials via the installation of electromagnetic ultrasonic measurement probes on in-service power grounding materials. The results from a substation grounding networkdemonstrate that the online corrosion monitoring system can obtain more precise grounding corrosion data and has more extensive application prospects compared with other monitoring methods.

Aerial Robots for Contact-Based Ultrasonic Thickness Measurements for Field Inspections

Aerial robotic systems, also referred to as drones, enable the collection of data on a scale and scope heretofore unimaginable. Field inspections at industrial sites using an aerial robotic inspection system that makes physical contact with a structure or asset as part of a nondestructive testing (NDT) or nondestructive evaluation (NDE) routine is safer than placing humans at elevation and enables more data to be gathered in less time. These aerial robotic systems are highly extensible and agile enabling safer, faster, and better inspections. Robotic inspection systems are forecast to grow exponentially this decade and beyond, as asset owners and service providers realize their economic value creation, increased data collection, and safety contributions.