• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.3
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• pp.73-81
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• 1998

In this paper, the necessity of developing effective nondestructive testing and monitoring techniques for the evaluation of structural integrity and performance is described. The evaluation of structural integrity and performance is especially important when the structures and subject to abrupt external forces such as earthquake. A prompt and extensive inspection is required over a large area of earthquake-damaged zone. This evaluation process is regarded as a part of performance-based design. In the paper, nondestructive testing and monitoring techniques particularly for concrete structures are presented as methods for the evaluation of structural integrity and performance. The concept of performance-based design is first defined in the paper followed by the role of evaluation of structures in the context of overall performance=based design concept. Among possible techniques for the evaluation, nondestructive testing methods for concrete structures using radar and a concept of using fiber sensor for continuous monitoring of structures are presented.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.3
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• pp.157-162
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• 2005

In order to evaluate the corrosion of reinforcing steel-bars (rebar) in concrete, a nondestructive evaluation by the half-cell potential method is currently applied. In this study, potentials measured on a concrete surface are compensated into those on the concrete-rebar interface by the inverse boundary element method (IBEM). Because these potentials are obtained three-dimensionally (3-D), 3-D visualization is desirable. To this end, a visualization system has been developed by using VRML (Virtual Reality Modeling Language). As an application, results of a reinforced concrete (RC) slab with corroded rebars are visualized and discussed.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.4
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• pp.317-322
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• 2013

This paper presents a new laser lock-in thermography (LLT) technique for nondestructive evaluation. LLT utilizes a modulated continuous wave laser beam as a heat source to obtain high fidelity thermal wave images even at the presence of background heat disturbances. The thermal waves propagating along the surface and through-the-thickness directions of a structure are visualized using newly developed laser lock-in amplitude and phase images, enhancing the detectability of surface and subsurface defects. The LLT technique is numerically investigated and experimentally validated using thermal images obtained from a steel specimen with low emissivity.

• Near Infrared Analysis
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• v.1 no.2
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• pp.9-20
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• 2000

Recently, near-infrared (NIR) spectroscopy and Raman spectroscopy have received keen interest as powerful techniques for nondestructive analysis of biological materials. The purpose of this review paper is to compare the advantages of NIR and Raman spectroscopy in the nondestructive analysis. Both methods are quite unique and often complementary. For example. NIR spectroscopy is very useful in monitoring in situ the content of components inside biological materials while Raman spectroscopy is very suitable for identifying micro-components on the surface of biological materials. In this article specific characters of the two spectroscopic methods are discussed first and then several examples of applications of NIR and Raman spectroscopy to the biological nondestructive analysis are introduced.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.2
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• pp.198-209
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• 2012

The present paper reviews the widely used surface microstructural investigation technique and micro/nano nondestructive evaluation(NDE) technique which is able to evaluate the surface and subsurface. In general, the micro/nano defects and microstructural state of surface have great influence on the mechanical, physical, and chemical properties of bulk materials. The investigation technique of surface microstructure is possible to evaluate the defects and microstructural state with high reliability. The various applications and developments of each inspection technique have been introduced. Consequently, it is thought that the technique developments and applications of micro/nano NDE in nondestructive industries are extensively possible hereafter.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.4
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• pp.418-430
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• 2012

The present paper reviews the micro and nano nondestructive evaluation(NDE) technique that is possible to investigate the surface and measure the acoustic properties. The technical theory, features and applications of the ultrasonic atomic force microscopy(UAFM) and scanning acoustic microscopy(SAM) are illustrated. Especially, these technologies are possible to evaluate the mechanical properties in micro/nano structure and surface through the measurement of acoustic properties in addition to the observation of surface and subsurface. Consequently, it is thought that technique developments and applications of these micro/nano NDE in advanced industrial parts together with present nondestructive industry are widely possible hereafter.

• Journal of the Korean Society for Nondestructive Testing
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• v.5 no.2
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• pp.58-70
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• 1986

• Journal of the Korean Society for Nondestructive Testing
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• v.5 no.2
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• pp.49-52
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• 1986

• Journal of the Korean Society for Nondestructive Testing
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• v.6 no.1
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• pp.31-38
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• 1986

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.2
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• pp.121-132
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• 1998