Persistent Link:
http://hdl.handle.net/10150/289714
Title:
Pipe inspection by cylindrically guided waves
Author:
Guo, Dongshan
Issue Date:
2001
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
In this research the cylindrically guided wave inspection technique is proposed for detecting the anomalies in a pipe. Efficient inspection of pipelines for internal and external damages is a challenging task in the chemical and power industries where long pipelines are used and the pipes are coated by insulating materials. Under traditional methods insulation coatings are removed at selected places, then the pipe wall thickness at these spots is measured by ultrasonic transducers. This is a time-consuming and expensive operation since the operation requires point-to-point examination. Guided wave ultrasonics, proposed in this research, is a much more efficient technique because by this technique long pipes can be inspected by removing insulation at only limited places. Detecting anomalies inside the pipe wall at a specific depth can be realized by correctly selecting a cylindrical guided wave and propagating that mode through the pipe. A new transducer holder mechanism has been designed and fabricated for pipe inspection by cylindrical guided waves. A number of advanced coupling mechanisms developed recently for large plate and pipe inspection require the presence of a coupling fluid between the ultrasonic transducer and the pipe or plate specimen. These mechanisms can be used for inspecting horizontal pipes and plates. Commercially available ultrasonic transducers have been used to generate compressional ultrasonic waves in the coupling medium. Those waves are converted to cylindrical guided waves in the pipe by the new coupling mechanism. The new coupling mechanism presented in this research uses solid material as the coupler and can be used equally well for inspecting horizontal as well as inclined or vertical pipes. The new coupling mechanism has been designed to generate efficiently different guided wave modes in the pipe. Different kinds of anomalies in pipes have been successfully inspected. The preliminary results show that a number of Lamb modes when generated properly by the new coupling mechanism are very sensitive to pipe defects. These experimental results along with the new design of the coupling mechanism are presented in this dissertation.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Applied Mechanics.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Civil Engineering and Engineering Mechanics
Degree Grantor:
University of Arizona
Advisor:
Kundu, Tribikram

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titlePipe inspection by cylindrically guided wavesen_US
dc.creatorGuo, Dongshanen_US
dc.contributor.authorGuo, Dongshanen_US
dc.date.issued2001en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractIn this research the cylindrically guided wave inspection technique is proposed for detecting the anomalies in a pipe. Efficient inspection of pipelines for internal and external damages is a challenging task in the chemical and power industries where long pipelines are used and the pipes are coated by insulating materials. Under traditional methods insulation coatings are removed at selected places, then the pipe wall thickness at these spots is measured by ultrasonic transducers. This is a time-consuming and expensive operation since the operation requires point-to-point examination. Guided wave ultrasonics, proposed in this research, is a much more efficient technique because by this technique long pipes can be inspected by removing insulation at only limited places. Detecting anomalies inside the pipe wall at a specific depth can be realized by correctly selecting a cylindrical guided wave and propagating that mode through the pipe. A new transducer holder mechanism has been designed and fabricated for pipe inspection by cylindrical guided waves. A number of advanced coupling mechanisms developed recently for large plate and pipe inspection require the presence of a coupling fluid between the ultrasonic transducer and the pipe or plate specimen. These mechanisms can be used for inspecting horizontal pipes and plates. Commercially available ultrasonic transducers have been used to generate compressional ultrasonic waves in the coupling medium. Those waves are converted to cylindrical guided waves in the pipe by the new coupling mechanism. The new coupling mechanism presented in this research uses solid material as the coupler and can be used equally well for inspecting horizontal as well as inclined or vertical pipes. The new coupling mechanism has been designed to generate efficiently different guided wave modes in the pipe. Different kinds of anomalies in pipes have been successfully inspected. The preliminary results show that a number of Lamb modes when generated properly by the new coupling mechanism are very sensitive to pipe defects. These experimental results along with the new design of the coupling mechanism are presented in this dissertation.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectApplied Mechanics.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineCivil Engineering and Engineering Mechanicsen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorKundu, Tribikramen_US
dc.identifier.proquest3026571en_US
dc.identifier.bibrecord.b42177637en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.