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RISS 인기검색어
- 검색키워드
- 저자 : Krishnan Balasubramaniam (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
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Long Range Cylindrically Guided Ultrasonic Wave Technique for Inspection
Balasubramaniam, Krishnan 한국비파괴검사학회 2003 한국비파괴검사학회지 Vol.23 No.4
In this paper, a review of the current status, on the use of long range cylindrically guided wave modes, and their interaction with cracks and corrosion damage in pipe-like structures will be discussed. Applications of cylindrically guided ultrasonic wave modes have been developed for inspection of corrosion damage in pipelines at chemical plants, flow-accelerated corrosion damage (wall thinning) in feedwater piping, and circumferential stress corrosion cracks in PWR steam generator tubes. It has been demonstrated that this inspection technique can be employed on a variety of piping geometries (diameters from 1 in. to 3 ft, and wall thickness from 0.1 to 6 in.) and a propagation distance of 100 meters or more is sometimes feasible. This technique can also be used in the inspection of inaccessible or buried regions of pipes and tubes. Like any non-destructive examination (NDE) method, the guided wave inspection method will have a defined false alarm rate and probability of detection, which will have to be determined. The associated signal-to-noise ratio of the NDE system under a field operating condition is also a factor that must be considered. The effects of the various parameters that influence the technique must be determined, such as accuracy, precision, and sensitivity guidelines, before attempting this technique for solving practical problems. Also, the procedures and limitations of applying this technique must be well understood for the successful implementation of this powerful technique. The method will substantially improve efficiency and reduce the inspection time and cost, especially when utilized as a precursor to a more detailed local inspection. Also, for critical have to be inspected, this technique provides an opportunity to perform NDE which otherwise may not be possible.
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Muralidharan, Ajith,Balasubramaniam, Krishnan,Krishnamurthy, C.V. Techno-Press 2008 Smart Structures and Systems, An International Jou Vol.4 No.4
An array based, outward monitoring, ultrasonic guided wave based SHM technique using a single transmitter and multiple receivers (STMR), with a small footprint is discussed here. The previous implementation of such SHM arrays used a phase-reconstruction algorithm (that is similar to the beam-steering algorithm) for the imaging of reflectors. These algorithms were found to have a limitation during the imaging of defects/reflectors that are present in the "near-field" of the array. Here, the "near-field" is defined to be approximately 3-4 times the diameter of the compact array. This limitation is caused by approximations in the beam-steering reconstruction algorithm. In this paper, a migration-based reconstruction algorithm, with dispersion correction in the frequency domain, is discussed. Simulation and experimental studies are used to demonstrate that this algorithm improves the reconstruction in the "near-field" without decreasing the ability to reconstruct defects in the "far-field" in both isotropic and anisotropic plates.
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A Simulation Tool for Ultrasonic Inspection
Krishnamurthy, Adarsh,Mohan, K.V.,Karthikeyan, Soumya,Krishnamurthy, C.V.,Balasubramaniam, Krishnan The Korean Society for Nondestructive Testing 2006 한국비파괴검사학회지 Vol.26 No.3
A simulation program SIMULTSONIC is under development at CNDE to help determine and/or help optimize ultrasonic probe locations for inspection of complex components. SIMULTSONIC provides a ray-trace based assessment for immersion and contact modes of inspection. The code written in Visual C++ operating in Microsoft Windows environment provides an interactive user interface. In this paper, a description of the various features of SIMULTSONIC is given followed by examples illustrating the capability of SIMULTSONIC to deal with inspection of canonical objects such as pipes. In particular, the use of SIMULTSONIC in the inspection of very thin-walled pipes (with 450 urn wall thickness) is described. Ray trace based assessment was done using SIMULTSONIC to determine the standoff distance and the angle of oblique incidence for an immersion mode focused transducer. A 3-cycle Hanning window pulse was chosen for simulations. Experiments were carried out to validate the simulations. The A-scans and the associated B-Scan images obtained through simulations show good correlation with experimental results, both with the arrival time of the signal as well as with the signal amplitudes.
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