Ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2005
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| Online Access: | http://hdl.handle.net/1721.1/7964 |
| _version_ | 1826207899661107200 |
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| author | Wang, Ji-yong, 1967- |
| author2 | Shi-Chang Wooh. |
| author_facet | Shi-Chang Wooh. Wang, Ji-yong, 1967- |
| author_sort | Wang, Ji-yong, 1967- |
| collection | MIT |
| description | Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003. |
| first_indexed | 2024-09-23T13:56:43Z |
| format | Thesis |
| id | mit-1721.1/7964 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T13:56:43Z |
| publishDate | 2005 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/79642019-04-11T00:49:31Z Ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials Wang, Ji-yong, 1967- Shi-Chang Wooh. Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering. Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering. Civil and Environmental Engineering. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003. Includes bibliographical references (leaves 141-145). Characterization of defect is one of the important objectives of nondestructive evaluation (NDE) for condition assessment of structures. Among many other NDE techniques, ultrasonic methods play a prominent role in the both quantitative and qualitative assessment of discontinuities in reinforced cementitious materials. Due to the heterogeneous nature of concrete, ultrasonic waves are highly scattered and attenuated, leading to the difficulty of concrete inspection using conventional ultrasonic techniques, including those that work well on relatively homogeneous materials such as metals. This thesis presents an advanced method for sizing and imaging of defects in reinforced cementitious materials. A two-dimensional, three-phase composite model of concrete is proposed to study the propagation and interaction behaviors of ultrasonic waves in concrete structures, and to gain a knowledge about wave diffraction with multiple cylindrical obstacles. The response of the modeled concrete structure to an incident ultrasonic pulse input signal (pulsed ultrasonic P-wave) is analytically investigated and simulated. A characteristic profile of the defect sizing as a function of focal depth is formulated via the synthetic focusing technique. A defect sizing parameter, called characteristic width, is obtained empirically to represent the defect sizing information for the concrete. Conventional 2-D ultrasonic B-scan imaging, for example, by migration, may introduce artifacts. In this thesis, the fundamental theory for synthetic aperture beam-forming through synthetic steering and focusing of array transducers is investigated. It is possible to achieve high spatial and temporal resolution ultrasonic image free of artifacts. A time-frequency signal processing and image reconstruction algorithm are also studied. The proposed defect sizing and imaging methodology is tested with numerically simulated ultrasonic waveform signals based on the mechanical properties of a custom-made concrete specimen. Experimental works confirm the feasibility of defect sizing and imaging of the method. With the knowledge about the concrete structures being tested this method may provide a useful tool for ultrasonic NDE application to reinforced cementitious materials. by Ji-yong Wang. Ph.D. 2005-08-24T23:19:25Z 2005-08-24T23:19:25Z 2003 2003 Thesis http://hdl.handle.net/1721.1/7964 54688858 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 156 leaves 7775811 bytes 7775571 bytes application/pdf application/pdf application/pdf Massachusetts Institute of Technology |
| spellingShingle | Civil and Environmental Engineering. Wang, Ji-yong, 1967- Ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials |
| title | Ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials |
| title_full | Ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials |
| title_fullStr | Ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials |
| title_full_unstemmed | Ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials |
| title_short | Ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials |
| title_sort | ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials |
| topic | Civil and Environmental Engineering. |
| url | http://hdl.handle.net/1721.1/7964 |
| work_keys_str_mv | AT wangjiyong1967 ultrasonicnondestructiveevaluationandimagingofdefectsinreinforcedcementitiousmaterials |