• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.3
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• pp.348-363
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• 2013

The use of I-Core sandwich panel has increased in cruise ship deck structure since it can provide similar bending strength with conventional stiffened plate while keeping lighter weight and lower web height. However, due to its thin plate thickness, i.e. about 4~6 mm at most, it is assembled by high power $CO_2$ laser welding to minimize the welding deformation. This research proposes a volumetric heat source model for T-joint of the I-Core sandwich panel and a method to use shell element model for a thermal elasto-plastic analysis to predict welding deformation. This paper, Part I, focuses on the heat source model. A circular cone type heat source model is newly suggested in heat transfer analysis to realize similar melting zone with that observed in experiment. An additional suggestion is made to consider negative defocus, which is commonly applied in T-joint laser welding since it can provide deeper penetration than zero defocus. The proposed heat source is also verified through 3D thermal elasto-plastic analysis to compare welding deformation with experimental results. A parametric study for different welding speeds, defocus values, and welding powers is performed to investigate the effect on the melting zone and welding deformation. In Part II, focuses on the proposed method to employ shell element model to predict welding deformation in thermal elasto-plastic analysis instead of solid element model.

• Journal of Fashion Business
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• v.20 no.3
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• pp.17-29
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• 2016

To develop baseball catcher leg guards, 3-dimensional (3D) methodologies, which are 3D human body data, reverse engineering, modeling, and printing, optimized guard design for representative positions. Optimization was based on analysis of 3D body surface data and subjective evaluation using 3D printing products. Reverse engineering was used for analysis and modeling based on data in three postures: standing, $90^{\circ}$ knee flexion, and $120^{\circ}$ knee flexion. During knee flexion, vertical skin length increased, with the thigh and knee larger in anterior area compared to the horizontal dimension. Moreover, $120^{\circ}$ knee flexion posture had a high radius of curvature in knee movement. Therefore, guard designs were based on increasing rates of skin deformation and numerical values of radius of curvature. Guards were designed with 3-part zoning at the thigh, knee, and shin. Guards 1 and 2 had thigh and knee boundaries allowing vertical skin length deformation because the shape of thigh and knee significantly affects to its performance. Guard 2 was designed with a narrower thigh and wider knee area than guard 1. The guards were manufactured as full-scale products on a 3D printer. Both guards fit better in sitting than standing position, and guard 2 received better evaluations than guard 1. Additional modifications were made and an optimized version (guard 3) was tested. Guard 3 showed the best fit. A design approach based on 3D data effectively determines best fitting leg guards, and 3D printing technology can customize guard design through immediate feedback from a customer.

• Journal of the Korean Chemical Society
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• v.21 no.5
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• pp.339-352
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• 1977

The authors' theory developed in the preceding Paper 1 was applied to plastic deformation of ceramics, metals, alloys and single crystals. For polycrystalline substances, the flow mechanisms due to dislocation movement and grain boundary movement appear together or separately according to the experimental conditions whereas for single crystals, only the mechanism of dislocation movement appears. The parameters appearing in the flow equations $({\alpha}_{d1},\;1/{\beta}_{d1})and\;({\alpha}_{gj}/X_{gj},\;1/{\beta}_{gj})$ (j = 1 or 2), and the activation enthalpies ${\Delta}H_{k1}^{\neq}$ (k = d or g) were determined and tabulated. Here, the subscript d1 indicates the first kind of dislocation flow units and gj expresses the jth kind of grain boundary flow units. The predictions of the theory were compared with experiment with good agreement. Concerning the activation enthalpies, it was found that ${\Delta}H_{d1}^{\neq}$ 〉{\Delta}H_{g1}^{\neq}$ and that the former agrees with the activation enthalpy for bulk self-diffusion whereas the latter agrees with the activation enthalpy for grain boundary self-diffusion. These facts support the adequacy of the authors' theory which is considered as a generalized theory of plastic deformation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.3
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• pp.593-608
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• 2018

If a problem occurs in the strut during the construction of the braced wall, they may cause excessive deformation of the braced wall. Therefore, in this study, the behavior of the braced wall and existing tunnel adjacent to excavation were investigated assuming that the support function of strut is lost during construction process. For this purpose, a series of model test was performed. As a result of the study, the earth pressure in the ground behind wall was rearranged due to the deformation of the braced wall, and the ground displacements caused the deformation of adjacent tunnels. When the struts located on the nearest side wall from the tunnel were removed, the deformation of the braced wall and the tunnel deformation were the largest. The magnitude of transferred earth pressure depended on the location of tunnel. The increase of the cover depth of tunnel from 0.65D to 2.65D caused the increase of the earth pressure by 25.6%. As the distance between braced wall and tunnel was increased from 0.5D to 1.0D, the transferred earth pressure increased by 16% on average. Horizontal displacements of braced wall by the removal of the strut tended to concentrate around the removed struts, and the horizontal displacement increased as the strut removal position is lowered. The tunnel displacement was maximum, when the cover depth of tunnel was 1.15D and the horizontal distance between braced wall and the side of tunnel was 0.5D. The minimal displacement occurred, when the cover depth of tunnel was 2.65D and the horizontal distance between braced wall and the side of tunnel was 1.0D. The difference between the maximum displacement and the minimum displacement was about 2 times, and the displacement was considered to be the largest when it was in the range of 1.15D to 1.65D and the horizontal distance of 0.5D.

• The Journal of the Petrological Society of Korea
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• v.11 no.2
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• pp.65-73
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• 2002

The wavy extinction of quartz grains can be used as a good indicator to show the degree of rock deformation. To determine degree of the rock deformation, intensity of wavy extinction (IWE) of quartz grains was measured by using polarizing microscope, digital camera, and NIH image (or Scion Image). In this experiment, the measurement was performed along the line perpendicular to the subgrain boundary of wavy extinction. IWE was measured when a quartz grain shows maximum extinction in polarizing microscope. NIH image was represented in terms of 256 gray-scale brightness, which was associated with intensity of the wavy extinction. IWE was determined by the degree of brightness versus the measuring length of a quartz grain. IWE was analysed in the distribution chart with the collection unit of 5. Regarding the characteristics of data distribution, the median between the mode and the median of the histogram is defined as a representative value for the IWE, and this value is subdivided into the five levels of rock deformation zones (lowest- or non-, low-, medium-, high-, and highest deformation) with their respective indices (D1, D2, D3, D4, and D5). The correlation between the Eonyang Granite and the Yangsan Fault was investigated by using the indices. The results indicate that IWE values decreased away from the fault.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.753-756
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• 2005

Rapid prototyping (RP) technologies are mainly performed by layered manufacturing (LM) process which manufactures 3D physical objects by depositing 2D sections in a direction. Thus, deformations are apt to occur in overhanging area of the RP processed part. Also, excessive adhesion between part and platform of the RP apparatus is generated. In order to prevent these problems, most of the RP technologies adopt support structure. Main element to support a part in the support structure is strand. In actual field, however, the number of strand is determined by the software operating reference guide or RP system operator's experience. In this paper, a methodology to determine the optimal strand spacing is presented through experiments and measurements for the SL part deformation by change of strand spacing and part weight in the support structure of the stereolithography.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.2
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• pp.117-121
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• 2005

This paper presents a 3D last design system utilizing an uniform foot pressure FFD method. The proposed uniform foot pressure FFD(UFPFFD) is operated on the rule of foot pressure unbalance analysis and FFD. The deformation factor of the UFPFFD is constructed on the FFD lattice with the foot pressure unbalance analysis on the measured 3D foot bottom shape. In addition, the control points of FFD lattice are decided on the anatomical point and the foot pressure distribution. The 3D last design result obtained from the proposed UFPFFD is saved as a 3D dxf data format. The experimental results demonstrate that the proposed last design guarantees the balanced foot pressure distribution against on the conventional last design method.

• Korean Journal of Remote Sensing
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• v.30 no.6
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• pp.719-730
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• 2014

Small BAseline Subset (SBAS) technique using multi master interferograms can be effective to detect surface deformation in forest area. In this paper, The analysis reveals area of 2-dimension surface deformation at Seguam Island in Aleutian Arc., Alaska. We acquired ERS-1/2 data from track 201 and 473 datasets on Seguam Island from 1992 to 2008. This study analyze surface deformation applying Differential Interferometry Synthetic Aperture Radar (DInSAR) and SBAS time series method using two adjacent tracks. As a results, it was calculated that subsidence -1~2 cm in LOS direction and - 2~3 cm in vertical direction. The horizontal direction was repeated contraction and expansion. The observation of 2-dimension displacements explained the volcanic activity on Seguam island. Also, it is believed to be used for basic data to estimate movements of magma source.

• Transactions of Materials Processing
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• v.20 no.8
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• pp.595-600
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• 2011

This paper investigates the effect of strain rate on the anisotropic deformation behavior of advanced high strength steel sheets. Uniaxial tensile tests were carried out on TRIP590 and DP780 steel sheets at strain rates ranging from 0.001/sec to 100/sec to determine yield stresses and r-values at various loading angles from the reference rolling direction. R-values were determined by the digital image correlation technique. Hill48 and Yld2000-2d yield functions were tested for their capability to describe the plastic deformation anisotropy of the materials. Initial yield loci were constructed using the Yld2000-2d yield function, which adequately described the anisotropic behavior of the materials. The shape of the initial yield loci was found to change with different strain rate, and the anisotropic behavior decreased with increasing strain rate.

• The KIPS Transactions:PartA
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• v.16A no.2
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• pp.61-68
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• 2009

We present a fast 3D shape deformation method that achieves smoothly deformed result by approximating a rigid transformation based on moving least squares (MLS). Our modified MLS formulation reduces the computation cost for computing the optimal transformation of each point and still keeps the rigidity of the deformed results. Even complex geometric shapes are easily, intuitively, and interactively deformed by manipulating point and ellipsoidal handles.