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Non-destructive evaluation with ultrasonic pulse velocity (UPV) in concrete structureLau, Connie K. Y. January 2005 (has links) (PDF)
Thesis (M.Sc.)--City University of Hong Kong, 2005. / At head of title: City University of Hong Kong, Department of Physics and Materials Science, Master of Science in materials engineering & nanotechnology dissertation. Title from title screen (viewed on Sept. 1, 2006) Includes bibliographical references.
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Non-destructive evaluation with ultrasonic pulse velocity (UPV) in concrete structureMong, Seng Ming. January 2005 (has links) (PDF)
Thesis (M.Sc.)--City University of Hong Kong, 2005. / At head of title: City University of Hong Kong, Department of Physics and Materials Science, Master of Science in materials engineering & nanotechnology dissertation. Title from title screen (viewed on Sept. 4, 2006) Includes bibliographical references.
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Ultrasonic Evalutation of Defects and Moisture Content of Lumbervan Dyk, Hermanus H. January 2004 (has links) (PDF)
No description available.
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Optimal Recovery of Elastic Properties for Anisotropic Materials through Ultrasonic MeasurementsSun, Miao January 2002 (has links) (PDF)
No description available.
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Design, development and testing of an automated system for measuring wall thicknesses in turbine blades with cooling channelsJiang, Zhengyi January 2016 (has links)
Cooling channels are designed in blades to protect the blades from damage at high temperature in a gas turbine. ELE Advanced Technology Ltd. is a UK company specialised in machining cooling channels in turbine blades using electro-chemical techniques. The wall thicknesses between these cooling channels and the surface of the turbine blade influences the performance of cooling channels and are required to be accurately machined and then inspected. At present, the company measures the wall thicknesses using a hand-held contact ultrasonic probe, which is time-consuming and not very accurate. In this project, an inspection machine has been designed and built for the purpose of automating the procedure of measuring wall thicknesses in turbine blades. The inspection machine measures wall thicknesses based on immersion ultrasonic testing technique and the actuator is a six-axis industrial robot controlled by a computer. Control algorithms have been developed to automate the entire measuring process. Acquired ultrasonic data is also automatically processed using Matlab scripts for wall thickness evaluation. However, prior to the ultrasonic measurement, the probe path has to be calculated. Matlab script has been developed to automatically calculate a probe path using a point cloud of the blade digitized on a CMM as an input. The calculation of the probe path, in general, involves triangulation, parameterisation and B-spline surface approximation. Normal 3D triangulation methods were tested; nevertheless, the results were unsatisfactory. Therefore, a triangulation algorithm is developed based on B-spline curve and 2D Delaunay triangulation. After the probe path is calculated, a localisation method, based on iterative closest point algorithm, is implemented to transform the probe path from CMM to the inspection machine. Several experiments were designed and conducted to study the capability of the ultrasonic probe. Experimental results confirmed the feasibility of using an immersion ultrasonic probe for measuring the wall thicknesses; however, the experiments revealed several limitations of immersion ultrasonic testing, such as the angle of incidence of ultrasonic waves must be maintained within an angular deviation of ±1° from the surface normal to achieve accurate test results. Wall thicknesses of three turbine blades from one batch were measured on the inspection machine. A CT scan image was used as reference to compare the measured wall thicknesses with results obtained using contact probes. The comparison showed the wall thicknesses measured on the inspection machine were much more accurate than using contact probes.
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Characterization of flaws and structural integrity by ultrasonic spectroscopy /Lewis, David Kent January 1986 (has links)
No description available.
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The effect of ultrasonic irradiation on ethyl alcohol - hydrogen peroxide - water mixturesGray, Walter C. January 1949 (has links)
no abstract provided by author / Master of Science
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Signal processing methods to quantify scattering of angle-beam shear waves from through-holes in platesKummer, Joseph W. 07 January 2016 (has links)
The objective of this thesis is to present analysis techniques that quantify the scattering of angle-beam ultrasonic waves from through-holes in plates. This topic is of interest because increased understanding of the scattering of ultrasonic waves by a defect is important for the development of many nondestructive evaluation (NDE) applications. Angle-beam techniques are commonly used in industry to detect and characterize defects, and many structures of concern have plate-like components. Scattering from through-holes is particularly important because cracks tend to form around fastener holes, which have high stress concentrations. In addition, varying boundary conditions within a fastener hole can change over the course of a structure’s lifetime and may have significant effects on NDE results. In this research, two signal processing techniques are developed to obtain scattering information from through-holes for a variety of fill conditions, including epoxy and complete and partial filling with metal inserts, using experimentally acquired wavefield measurements. Experimental procedures for acquiring wavefields, which measure the out of plane motion of ultrasonic waves on the surface of a specimen and allow for the visualization and characterization of propagating waves, are presented. Methods for obtaining radial and directional energy maps, which quantify scattering as a function of scattered angle and phase velocity, are described. In addition, baseline subtraction is used to obtain scattering patterns for both methods, which quantify scattering as a function of polar angle for each wave mode present in the wavefield. These techniques are applied to wavefield measurements from through-holes with various fill conditions to investigate the effects of boundary conditions on ultrasonic scattering. A comparison of the radial and directional energy mapping techniques, discussing the strengths and weaknesses of each approach, is provided, and recommendations are made for future work.
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Evaluation of adhesively bonded steel sheets using ultrasonic techniquesTavrou, Chrysostomos Kyriacou, stavrou@swin.edu.au January 2005 (has links)
Adhesives have presently reached a stage where they have become part of everyday
life both in a professional sense as well as for household applications. They offer
advantages that in many respects surpass other joining processes such as bonding
of large areas, joining a wide range and dissimilar materials; and without the need for
special tooling or operator training, that is often required by many other joining
processes. They are of course not a panacea to all fastening applications, but they
can easily be described as the most versatile and most widely used joining method at
present.
Engineering applications have also benefited from the advantages offered by
adhesives, but they are not as liberally used due to the severe consequences that
may result from bond failure. Although adhesives can demonstrate their ability to
fulfil the joining strength requirements under laboratory conditions, their application in
industry proved to be not as reliable as expected. A number of parameters that can
easily be controlled under laboratory conditions such as temperature, humidity,
surface preparation and uniform adhesive application are not as easily observed in
industry. Quality assurance during manufacturing can achieve excellent results;
however even in these cases the probability of having adhesive bond defects is still
present. Therefore, there is a need for post process inspection of adhesive bonds
where risk levels require higher reliability than what is offered though process quality
control.
Adhesive bond inspection is a well researched area with respectable outcomes. Non
destructive inspection techniques such as x-ray, thermal, and ultrasonic are well
utilised in the inspection of adhesive bonds. However, despite all the effort in this
area for more than forty years, there is still no singular technique that can achieve the
confidence level required in some engineering applications. Therefore, the need for
continuing research in the area of non-destructive evaluation of adhesive bonds is as
necessary today as it�s ever been. The research presented in this thesis, continues
in the same endeavour as many other researchers; that of achieving the ultimate
technique in adhesive bond inspection, capable of reaching the confidence level
required for all engineering applications.
The research in the thesis commenced with coverage of adhesives used for
engineering applications and a study of the adhesion science that was considered
necessary to enable an informed approach to the problem. Adhesive bond failure is
also analysed through a literature survey as well as experimental tests on standard
specimens. At the completion of the literature survey and preliminary tests, a
decision was taken to follow the ultrasonic path of non-destructive testing of adhesive
bonds. The reasons for this, are clearly outlined in the main body of this thesis but in
summary, the literature has shown that ultrasonic evaluation is the most widely used
technique by industry. Therefore, improvements on data analysis using existing
techniques that exploit ultrasonic inspection have the potential to reach the widest
spectrum of industrial applications.
Ultrasonic inspection equipment was sourced that was capable of achieving
experimental results to the accuracy level required in this research. A precision test
rig was designed and constructed that was subsequently calibrated using computer
based statistical techniques to ensure the validity of all results. Other ancillary
equipment, such as a portable tensile testing device were also designed and
constructed during the research as it became necessary.
Research concentrated on techniques found to be inadequately researched in this
domain. The first technique evaluated was to measure bond quality through the
stress distribution in adherent and adhesive. Computer based Finite Element
Analysis showed that the ability to detect variation in stress distribution at the
adhesion interface is capable of revealing the local bond strength. Having found that
there is no technique available at present that can measure the stress distribution at
the interface, a different direction was taken that showed potential in achieving
excellent quantitative results in the analysis of ultrasonic signals from adhesive
bonds. This technique was rigorously evaluated and the results are systematically
reported in this work.
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The application of ablative laser ultrasonics to an aluminum plate, titanium tube, and welded jointsButler, Chad L. 04 June 1996 (has links)
Laser ultrasonics can be used to nondestructively evaluate structures to determine the existence and location of surface and interior flaws. The goal of this research was to determine if laser ultrasonic techniques can be applied to the inspection of aluminum plate. titanium tubes, and large welded plate structures. The research was carried out with a Q-switched pulsed ruby laser emitting light of 694 nm wavelength. Ultrasonic waves were experimentally generated and recorded in the aluminum plate and the titanium tube. A comprehensive literature study was completed to determine if the technique can be applied to welded structures. For the two experimental cases, the ultrasonic waves were received by a piezoelectric pinducer which was located on the opposite side of the plate. and on the outside of the tube. A digital oscilloscope captured the signals from the pinducer. The signals were then analyzed to determine echo spacing and frequency content. The physical characteristics of the laser pulse such as the energy and full-width-half-height and amplitudes were measured via a photodiode system and a calorimeter. The aluminum plate confirmed that the system was functioning properly, as the ultrasonic echoes that were generated matched the expected results from previous experimentation. The titanium tube data turned out to be difficult to interpret due to the complex geometry and mode conversion. The welding research showed that ultrasound can be used to identify many types of flaws in a welded joint. Currently, few researchers have applied the laser based ultrasound to flaw detection in finished welds, although several have looked at using the laser ultrasound as an input to a control system for a weld in progress. The literature research uncovered the need for further studies on the application of laser based ultrasound to flaw detection in completed welds. / Graduation date: 1997
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