• Structural Engineering and Mechanics
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• v.72 no.5
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• pp.653-673
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• 2019

This work investigates a novel quasi-3D hyperbolic shear deformation theory is presented to discuss the buckling of new type of sandwich plates. This theory accounts for both shear deformation and thickness stretching effects by a hyperbolic variation of all displacements through the thickness. The enhancement of this formulation is due to the use of only five unknowns by including undetermined integral terms, contrary to other theories where we find six or more unknowns. It does not require shear correction factors and transverse shear stresses vary parabolically across the thickness. A new type of FGM sandwich plates, namely, both FGM face sheets and FGM hard core are considered. The governing equations and boundary conditions are derived using the principle of virtual displacements. Analytical solutions are obtained for a simply supported plate. The accuracy of the present theory is verified by comparing the obtained results with quasi-3D solutions and those predicted by higher-order shear deformation theories. The comparison studies show that the obtained results are not only more accurate than those obtained by higher-order shear deformation theories, but also comparable with those predicted by quasi-3D theories with a greater number of unknowns.

• Structural Engineering and Mechanics
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• v.61 no.1
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• pp.49-63
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• 2017

This paper presents an original hyperbolic (first present model) and parabolic (second present model) shear and normal deformation theory for the bending analysis to account for the effect of thickness stretching in functionally graded sandwich plates. Indeed, the number of unknown functions involved in these presents theories is only five, as opposed to six or even greater numbers in the case of other shear and normal deformation theories. The present theory accounts for both shear deformation and thickness stretching effects by a hyperbolic variation of ail displacements across the thickness and satisfies the stress-free boundary conditions on the upper and lower surfaces of the plate without requiring any shear correction factor. It is evident from the present analyses; the thickness stretching effect is more pronounced for thick plates and it needs to be taken into consideration in more physically realistic simulations. The numerical results are compared with 3D exact solution, quasi-3-dimensional solutions and with other higher-order shear deformation theories, and the superiority of the present theory can be noticed.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.663-666
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• 2008

For a fill dam, when a long time has passed since its completion, it is very hard to judge its safety and to maintain effectively it due to limitation and restriction in data showing safety status. Conventional method based on a specific point data by surface settlement gauge is commonly used to define deformation characteristic of dam. However, point data-based deformation analysis cannot provide deformation data of the entire dam. In this study a state-of-the-art terrestrial laser scanning technology is introduced to analyze the entire deformation of dam. As a result, it is known that 3D scanning technique can also be effectively used in evaluating dam safety and then establishing adequate maintain plan.

• Smart Structures and Systems
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• v.22 no.3
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• pp.303-314
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• 2018

An original quasi-3D hyperbolic shear deformation theory for simply supported functionally graded plates is proposed in this work. The theory considers both shear deformation and thickness-stretching influences by a hyperbolic distribution of all displacements within the thickness, and respects the stress-free boundary conditions on the upper and lower surfaces of the plate without using any shear correction coefficient. By expressing the shear parts of the in-plane displacements with the integral term, the number of unknowns and equations of motion of the proposed theory is reduced to four as against five in the first shear deformation theory (FSDT) and common quasi-3D theories. Equations of motion are obtained from the Hamilton principle. Analytical solutions for dynamic problems are determined for simply supported plates. Numerical results are presented to check the accuracy of the proposed theory.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.4
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• pp.365-374
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• 2004

Steel bridges, which have been damaged by load and corrosion, need repair or strengthening. That is a cause of decreasing the durability of structure. In order to solve these problems, welding repair and strengthening methods can be considered. In general, cutting and welding procedure is carried out during the repair welding. Therefore, the investigation of the behavior of residual stress and deformation generated by cutting and welding is very important for safety of structure. Residual stress and deformation produced by gas cutting and arc welding were analyzed using 2D and 3D thermal elasto-plastic FEM. According to the results, the magnitude of temperature was analyzed by 2D-FEM is smaller than that was analyzed using the 3D-FEM at the start and end edge of flange. And the magnitude and distribution of residual stress of perpendicular direction of the cutting line and welding line was analyzed by the 2D-FEM was similar to that was analyzed by 3D-FEM. Therefore, it is possible to predict cutting and welding residual stress by 2D and 3D FEM.

• Journal of Fashion Business
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• v.16 no.2
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• pp.151-162
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• 2012

The industry-wide development of digital technologies has also affected the textile and fashion industries immensely. The applications of 3D technology, virtual reality, and/or augmented reality systems have helped to create novel fashion brands based on the marriage of IT and textile/fashion industries. 3D digital virtual clothing systems have been developed to help the textile and fashion industries in terms of the planning, manufacturing, marketing and sales sectors. So far, most of the development effort for the 3d virtual clothing systems has been focused on the woven fabrics. The characteristics of woven fabrics differ from those of knitted fabric. Since the physical structures and mechanical properties of the knitted fabrics are definitely different from those of woven fabrics, the simulation process for the knitted fabrics should follow different approaches. The loops in a knitted fabric deform easily. The deformation results in a readily stretchable fabric appearance. Cloth simulation mostly employs models that approximate the mechanical properties of linear elastic planes. This simulation scheme does not, however, describe well enough the behavior of knitted fabrics, which deviate largely from the linear isotropic material characteristics. This study aims at characterizing the tensile deformation and surface textures of a knitted fabric product. Tensile deformation curves for the wale, course, and bias direction are analyzed. The surface texture of the knitted fabric is analyzed by using a 3-dimensional scanning device.

• The Journal of the Petrological Society of Korea
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• v.23 no.2
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• pp.105-117
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• 2014

The Ogcheon and Joseon Supergroups are distributed in the Bonghwajae area, Jecheon-si, Chungcheongbuk-do, Korea which is located in the northeastern fore-end of the Ogcheon Metamorphic Zone. This paper researched the geological structures based on the geometric and kinematic characteristics and the forming sequence of the major multi-deformed rock and microstructures. Most of regional foliations are not the S0 bedding but the S0-1 composite foliations defined by the preferred orientation of stretching minerals, some are recognized as the S0-1-2 composite foliations by the preferred orientation of insoluble opaque minerals and cleavage lamella. The geological structures were formed at least by three phases of deformations i.e. NNE-SSW trending D1, E-W trending D2, N-S trending D3 compressions. The S0-1 composite foliation, which shows a similar zone-distribution trend of the constitution strata of the Ogcheon and Joseon Supergroups, trended WNW before D2 deformation, but it was reoriented into N-S which was parallel to the trend of S2 foliation by D2 deformation, and it was rearranged into NW, NE, N-S trends as it is now by D3 deformation. The structural characteristics of each deformation phase and the deformation history are very similar to those in the eastern domain of Busan area into which the Ogcheon and Joseon Supergroups in this area are extended as NNW trend. It is expected to be very valuable data in interpreting the tectonic evolution of the northeastern fore-end of the Ogcheon Metamorphic Zone.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.13 no.1
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• pp.69-76
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• 1995

This study is the 3-D precision deformation measurement of a bridge, obtain results of precision control points by GPS and 3-D measurement system and develope efficientlty technices which can solve precision 3-D analysis by CRP In the result, we could overcome the problems of former control point measurement in the way of the combination system of GPS and 3-D measurement system to positioning decision of reference points and control points. Then we could symplify old measurement process on the 3-D deformation analysis of a linear structure and complement parted analysis fault of measurement instrument.

• Economic and Environmental Geology
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• v.45 no.4
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• pp.385-396
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• 2012

The geochemical high-grade uranium anormal zone has been reported in the Shinbo mine and its eastern areas, Jinan-gun, Jeollabuk-do located in the southwestern part of Ogcheon metamorphic zone, Korea. In this paper is reported the time-relationship between deformation and growth of metamorphic minerals in the eastern area of Shinbo mine, which consists of the Precambrian metasedimentary rocks (quartzite, metapelite, metapsammite) and the age-unknown pegmatite and Cretaceous porphyry which intrude them, and is considered the relative mineralization time on the basis of the previous research's result. The D1 deformation formed the straight-type Si internal foliation which is defined mainly as the arrangement of elongate quartz, biotite, opaque mineral in andalusite porphyroblast. The D2 deformation, which is defined by the microfolding of Si foliation, formed S2 crenulation cleavage. It can be divided into two sub-phases, early crenulation and late crenulation. The former occurs as the curvetype Si foliation in the mantle part of andalusite. The latter occurs as S1-2 composite foliation which warps around the andalusite. The andalusite porphyroblast began to grow under non-deformation condition after the formation of S1 foliation which corresponds to the straight-type Si foliation. It continued to grow before the late crenulation phase. The age-unknown pegmatite intruded after the D2 deformation and grew the fibrous sillimanite which random masks the S1-2 composite foliation. The D3 deformation formed F3 fold which folded the S1-2 composite foliation, D2 crenulation, fibrous sillimanite. It means that the intrusion of pegmatite related to the growth of the fibrous sillimanite took place during the inter-tectonic phase of D2 and D3 deformations. The retrograde metamorphism is recognized by the chloritization of biotite and two-way cleavage lamellae which is parallel to the S1-2 composite foliation and the F3 fold axial surface in the andalusite porphyroblast. It occurred during the D2 late crenulation phase and D3 deformation. In considering of the previous research's result inferring the most likely candidate for the uranium source rock as pegamatite, it indicates that the age-unknown pegmatite intruded during the inter-tectonic phase of D2 and D3 deformations, i.e. during the retrograde metamorphism related to the uplifting of crust, and formed the uranium ore zone around the Shinbo mine.

• 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.