AbstractThis paper presents the development of a steel-climbing bicycle robot integrated with an ultrasonic sensing device towards autonomous thickness measurement of steel bridge members. The ...bicycle-like robot has two magnetic wheels controlled by two independent steering actuators, which navigates on various steel surfaces (flat, curved, rough, concave, and convex). The compact ultrasonic sensing device is capable of high-voltage pulse excitation, filtering/amplification of the received ultrasonic signal, and high-speed analog-to-digital conversions (up to 80 MHz). Along with the ultrasonic sensing device, the robot carries a dual element transducer, an automatic gel couplant dispenser, a position tracking sensor, and a camera. A mounting/retrieving mechanism of the transducer is designed to ensure the reliable contact of the transducer on steel surfaces. The camera view assists an operator to safely navigate the robot to measurement locations, properly dispense gel couplant, and firmly press the transducer on a measurement surface. The automated robot localization provides accurate thickness measurement locations, which are mapped real-time in three-dimensional (3D) space together with the robot’s travel path. We validate the performance of the developed system in several indoor and outdoor tests. Weblink to a supplementary video demonstrating the robot’s maneuverability and ultrasonic thickness measurements is available in the Data Availability Statement of this article.
•The research investigates parameters in Ultrasonic Thickness Measurement (UTM).•Each parameter has an impact on measurement result.•The measurement results should be stated with associated ...measurement uncertainty.•This paper presents mathematical model for UTM uncertainty estimation.
Ultrasonic thickness measurement (UTM) is regularly applied and important NDT (Non destructive) method in structure and component integrity assessment. This method provides wall thickness determination by measuring the transit time of ultrasonic pulses between two walls. This widely applicable ultrasonic technique provides quantitative information about specimen wall thickness and belongs to the area of metrology activities.
In NDT laboratory accreditation process, the EA 4/15 guideline is required, which defines estimation of measurement uncertainty in those methods which quantitatively display the measurement result. However, in the area of ultrasonic measurement of the wall thickness, the result is displayed without the relevant estimation of measurement uncertainty, so there is no specified doubt in the obtained measurement result.
This paper presents mathematical model for ultrasonic thickness measurement uncertainty estimation by using Monte Carlo simulation.
•FAC experiment at same working condition as NPP secondary pipe materials.•Wall thinning rate measurement using high precision ultrasonic.•Wall thinning rate of materials with different chromium ...content.
Wall thinning rate is an important issue during design of CAP1400 nuclear power plant (NPP) secondary loop. A single-phase flow accelerated corrosion (FAC) test loop was established to simulate the typical working condition of the secondary loop. The wall thinning rate of A335P11 and 20# steel elbow was measured using high precision ultrasonic sensor on the test loop. The results show that elbow part has higher thinning rate than that at straight part, especially at intrados of elbow. Wall thinning rate of 20# steel elbow is about three to four times of that A335P11 steel because of the high contents of Chromium at A335P11. According to the FAC test results it shows that A335P11 could be one of the preferred pipe material of CAP1400 secondary loop.
The electromagnetic-acoustic method is applied in the control of the electrically conductive products thickness. This method is based on the electrodynamic interaction of eddy currents induced in an ...electrically conductive material with an external magnetic field. Acoustic waves are generated with multiple reflections from the media interface. The recorded signal reflected allows determining the product thickness. Electromagnetic-acoustic transducer includes a magnetic system, generating and receiving coils. Thickness measurement accuracy of the control object is determined by the geometry of the generating and receiving coils, as well as the size of the gap between them. To assess this effect by the experimental data is rather difficult task. The acoustic wave propagation numerical model in a plate with electromagnetic-acoustic thickness measurement is proposed and developed for the problem solution. The numerical model is implemented in the COMSOL Multiphysics software environment using a discontinuous high-order Galerkin method with time explicit integration scheme. Model adequacy was confirmed using the results of a full-scale experiment, for which a specialized electromagnetic-acoustic thickness gauge with a transducer and a thickness gauge were used. To estimate the uncertainty of thickness measurements, an array of values of the received signal was processed in the MathCad software environment. The adequacy of the model has been confirmed by comparing the simulation results with a full-scale experiment. The influence of the transducer design on the thickness measurement accuracy was estimated. Conclusions are drawn, as well as general recommendations for the development of an electromagneticacoustic transducer, and methods for object thickness measuring are given based on the investigation results. The results can be used in the design of an electromagnetic-acoustic transducer and in the development of thickness measurement techniques.
A three-dimensional surface mapping method for ultrasonic thickness measurements is proposed to enable the dimensions and positions of measured values obtained by the conventional ultrasonic ...thickness gauges and flaw detectors on curved surfaces to be determined. The proposed system
consists of a laser pattern generator and image processing methods. The laser grid produced by the pattern generator is projected onto the surface of the item to be inspected, mathematical relationships are developed to localise the grid nodes on the inspection surface and images are then
captured using a complementary metal-oxide semiconductor (CMOS) camera. An image processing algorithm is developed to plot the scanned surface. The measurements performed using a thickness gauge are correlated with the plotted surface, which will enable thickness mapping. The experiments were
carried out on a pipe with an artificial metal loss defect and the results showed that the developed method can accurately locate measured thickness values on a three-dimensional plotted surface.
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.
The North Sea, with a coast length of 1590 km, is amongst the most active commercial shipping route in the world, and is subject to harsh environmental conditions throughout the year. Coastal ...protecting measures defend waterways around the North Sea coast against storms, rising sea levels, and corrosion. Quay walls, one of the most widely used coastal protection system, have been one of the fundamental building blocks of the economic system. They are designed to enable ship moorings and absorb impacts from vessels. Further, quay walls are used to allow shipment of goods to the vessels using heavy equipment. They must withstand varying water levels, environmental conditions, loads being carried in and out of the ports. Periodic asset maintenance of quay walls is therefore crucial to ensure uninterrupted services and minimum downtimes, and to prevent catastrophic damages and loss of lives.Quay walls are subject to numerous structural damages including interlock damage, scouring, impact damage, and corrosion of concrete, reinforcement, and steel components. Continuous inspection programs are required to timely maintain, and repair associated infrastructure. Conventionally, the underwater sections of the quay wall are inspected by professional divers carrying underwater cameras and sensors to perform visual and ultrasonic thickness measurement. However, diver-based methodologies are often restricted by limited operational durations, depths, and safety risks. Further, the waterways connected to the North Sea are subjected to numerous challenges including as dense marine growth, dynamic variations in water visibility, underwater currents or flow, and operation in confined spaces. To overcome these challenges and inherent risks associated with manned underwater operations, an alternative inspection approach using remotely operated robotic vehicles (ROV) indigenously developed by Planys BV is proposed in this paper. ROVs have several key advantages in comparison to the conventional-manned operations including unlimited endurance, and depth of operation, live video streaming, improved data quality, and defect geotagging to improve result repeatability.These ROVs are controlled remotely from a safe location by a pilot. They are also compact and lightweight, deployable by a crew of two personnel. They carry underwater cameras and lights for live visual inspection, sonic and ultrasonic transducers for sonar surveys and ultrasonic thickness measurement, respectively. This paper presents a case study of inspecting sheet pile infrastructure using ROVs in waterways connecting the North Sea in Western Europe. Key details explaining the components of the ROV, and methodology of operation are discussed. Exemplary results from visual inspection and ultrasonic thickness measurement are depicted, showing satisfactory quality of data collected. Furthermore, details of data analysis and representation implementing state-of-the-art digital analysis dashboard to enable rapid and accurate interpretation, are presented.Key limitations of using freely swimming ROVs are described from the viewpoint of operational efficiencies and rate of inspection. Recommendations on development of next generation of robotic crawler devices for enhanced commercially viable inspection routines are discussed. The work presented in the paper may be of interest to authorities, asset owners and managers of marine assets, operating both, inland and nearshore.
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