• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.734-738
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• 2012

A comprehensive vibration assessment program for the Advanced Power Reactor 1400 reactor vessel internals is established in accordance with the United States Nuclear Regulatory Commission Regulatory Guide 1.20 Revision 3. This paper is related to instruments and measurement locations based on the vibration and stress response analysis results at the inner barrel assembly top plate in the reactor. The analysis results of the inner barrel assembly top plate in the reactor show that the deterministic stress and deformation due to the reactor coolant pump induced pressure pulsations are larger than the random stress and deformation induced by the flow turbulence. The selection of the instruments and measurement locations at Inner barrel assembly top plate in the reactor is essential requirements and very important study process for the vibration and stress measurement program in comprehensive vibration assessment program for the Advanced Power Reactor 1400 reactor vessel internals.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.5
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• pp.474-479
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• 2012

A comprehensive vibration assessment program for the advanced power reactor 1400(APR1400) reactor vessel internals is established in accordance with the united states nuclear regulatory commission regulatory guide 1.20 revision 3. This paper is related to instruments and measurement locations based on the vibration and stress response analysis results of the inner barrel assembly top plate in APR1400. The analysis results of the inner barrel assembly top plate in the reactor show that the deterministic stress and deformation due to the reactor coolant pump induced pressure pulsations are larger than the random stress and deformation induced by the flow turbulence. The selection of the instruments and measurement locations at inner barrel assembly top plate in the reactor is essential requirements and very important study process for the vibration and stress measurement program in comprehensive vibration assessment program for APR1400 reactor vessel internals.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.6
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• pp.555-562
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• 2019

This paper presents soil deformation measurement in model chamber based on photogrammetry. We created an aluminum framed acrylic model chamber with soil inside and applied photogrammetry to measure soil deformation caused by loading tests. The soil consists of 40% black and 60% regular sand to create image contrast in soil images. In preprocessing, the self camera calibration was carried out for IOPs (Interior Orientation Parameters), followed by the space resection to estimate EOPs (Exterior Orientation Parameters) using control points located along the aluminum frame. Image matching was applied to measure the soil displacement. We tested different matching window sizes and the effect of image smoothing. Experimental results showed that 65x65 pixels of window size produced better soil deformation map and the image smoothing was useful to suppress the matching outliers. In conclusion, photogrammetry was able to efficiently generated soil deformation map.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.335-342
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• 2003

The method of measuring ground deformation modulus, in situ-testing has the disadvantage where the exam number is limited because it needs counter weight and a lot of measurement times. Recently, it has supplemented this problem and the equipments by which measurement can be made quickly are developed and applied in field., That is Falling Weight Deflectometer(FWD), Light Drop Weight Tester(LDWT), Geogauge. Light Drop Weight Teste.(LDWT) is introduced firstly in the name of ‘a lightweight fall circuit tester for a railroad public corporation’ by KTX. Since KTX introduced LDWT, a number of research organizations have used LDWT to find out domestic standard for quality management of base ground. In this study we used ZFG 02 which was manufactured by Stendal in Germany and measured the dynamic deformation modulus in soil box and in-situ. And we analyzed the correlation of the dynamic deformation modulus with static deformation modulus based on plate test in the same ground.

• Polymer(Korea)
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• v.38 no.5
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• pp.645-649
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• 2014

The causes of residual stress in an injection molded part are high temperature variation and shear stress during molding process. Chemical cracking test is one of the methods of measuring residual stress and cracks are developed according to the degree of residual stress. In this study, the relationship between chemical cracking and exerted stress have been investigated. Deformation jig was designed and used to give a stress through deformation in a specimen. Specimens were molded by a hot press using polycarbonate (PC) and annealed to remove residual stresses in the specimens. Specimens were fixed in the deformation jig and immersed into the solvent to create cracks in the specimens. Solvents were prepared by using tetrahydrofuran and methyl alcohol. As stress accordance with the deformation in the specimen increased, the frequency and density of cracks in the specimen also increased. The results of this study can be used for the measurement of residual stress quantitatively in an injection molded PC product using a chemical cracking method.

• Journal of the Korean GEO-environmental Society
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• v.17 no.8
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• pp.39-44
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• 2016

Ground deformation around construction site in urban area where typically adjacent structures are located needs to be strictly controlled. Accordingly, it is very important to precisely monitor the ground deformation. Settlement beacon is typically employed to measure the ground deformation, but meanwhile the rapid development in electronic technology enables 3D image scanner to become available for measuring the ground deformation profile in usual construction sites. With respect to the profile measurement, the 3D scanner has an advantage, whereas its accuracy is somewhat limited because it does not measure the displacement directly. In this paper, we developed a conditional merging technique to combine the ground displacement measured from settlement beacon and the profile measured by the 3D scanner. Synthetic ground deformation profile was generated to validate the proposed technique. It is found that the ground deformation measurement error can be reduced significantly via the conditional merging technique.

• Structural Engineering and Mechanics
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• v.9 no.4
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• pp.339-347
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• 2000

The creep deformation of pure bending (hold constant moment for a period of time) tests were conducted in this paper. Thin-walled tubes of 304 stainless steel were used in this investigation. The curvature-ovalization measurement apparatus, designed by Pan et al. (1998), was used for conducting the present experiments. It has been found that as soon as the creep deformation is started, the magnitudes of the tube curvature and ovalization of tube cross-section quickly increase. The magnitudes of the creep curvature and ovalization of tube cross-section increase fast with a higher hold moment than that with a lower one. Owing to the continuously increasing curvature during the creep deformation, the tube specimen buckles eventually.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.157-163
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• 2006

Vibration and deformation sensing control of lightweight structures using optical fiber sensor technology is introduced in this presentation. This paper shows several examples of vibration control and deformation estimation for structures using these optical fiber sensor systems. Among various optical fiber sensors, in this paper, two types of optical fiber sensors, Fabry-Perot Interferometer(EFPI) and Fiber Bragg Grating(FBG) sensors, are mainly dealt with. Fiber optic sensors show many advantages over conventional strain gages for the measurement of vibration and deformation of lightweight structures.

• Transactions of Materials Processing
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• v.10 no.1
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• pp.42-52
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• 2001

The static softening mechanisms of 304 stainless steel were studied by hot torsion test. The interrupted deformation tests were performed In the range of 900~$1100^{\circ}C$ and 5.0$\times$$10^{-2}$- 5.0$\times$$10^0$/sec. The metadynamic recrystallization (MDRX) could be distinguished from the static recrystallization (SRX). Comparison of the softening kinetics between MDRX and SRX showed that the rate of MDRX was more rapid than that of SRX for the same deformation variables. To the exact prediction of MDRX, the MDRX parameter, which could be simultaneously estimated by the interpass time and Zener-Hollomon parameter, was developed. The time lot 50% MDRX, $t_{0.5} was modeled using the deformation parameters : $t_{0.5} = 1.33\times10^{-11}$ $\.\varepsilon^{-0.41}$ D exp(230.3kJ/mol/RT) and the predicted value was very correspondent with the measurement. It was found that the static parameters such as interpass time can control the dynamic states in the several successive deformation process.

• Tunnel and Underground Space
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• v.12 no.2
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• pp.99-106
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• 2002

To use the early measured data of tunnel deformation in but analysis, the relationship between these values find final deformation data were studied. Panet\`s exponential and fraction equations successfully approximate the convergence of the hard rock tunnels. Measured deformation data of ID location, $U_{1D}$ show that they can be lilted to linear equations but should not be used to estimate potential deformation before measurement, $C_{0}$. Early measured data $U_{1D}$ $U_{2D}$ , and final deformation $ U_{L}$ showed linear correlations. It proved that estimated data of final deformation from early measured ones can be used as input parameters for back analysis.