• 터널과지하공간
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• 제5권2호
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• pp.95-103
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• 1995

In this paper the stress redistribution around tunnel face was analyzed by using a three-dimensional finite element model. The effects of in-situ stress levels, excavation sequences, stiffness difference between the hard ground and the weak zone on the stress redistributions were considered. Displacement and stress changes at tunnel crown, side wall, and invert were investigated throughout the sequential excavation. To show ground response, percentage of the displacement and stress variations are used as a function of normalized distance that is between the face and monitoring section. Preceding displacements and stress variations were presented to be adopted in the two-dimensional tunnel analysis.

• 패션비즈니스
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• 제17권6호
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• pp.28-43
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• 2013

Recent trends toward the collaborations among various sectors of academia and research areas have brought interests and significances in new activities especially in the fashion and textile areas. One of the collaboration examples is the recent research projects on 3D virtual clothing systems based on the 3D CAD software. The 3D virtual clothing systems provide simulated apparels with high degrees of fidelity in terms of color, texture, and structural details. However, since real fabrics exhibit strong nonlinearity, anisotropy, viscoelasticity, and hysteresis, the 3D virtual clothing systems need fine tuning parameters for the simulation process. In this study, characteristics of silk fabrics, which are woven by using degummed silk and raw silk yarns, are being analyzed and compared. Anisotropic properties may be measured as warp and filling direction properties separately in woven fabrics, such as warp tensile stress or filling bending rigidity. Hysteretic properties may be measured as bending hysteresis or shear hysteresis by using KES measurements. These data provide deformation-force relationships of the fabric specimen. Three-dimensional effects obtained when using these characteristic fabrics are also analyzed. The methods to control the three-dimensional appearance of the sewn fabric specimens when utilizing a programmable microprocessor-based motor device, as prepared in this study, are presented. Based on the physical and mechanical properties measured when using the KES equipment, the property parameters are being into a 3-dimensional virtual digital clothing system, in order to generate a virtual clothing product based on the measured silk fabric properties.

• 한국지반공학회논문집
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• 제24권2호
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• pp.27-36
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• 2008

3차원 수치해석에 의해 굴착면적비(L/B)인 굴착 폭 B와 굴착면의 길이 L의 변화에 따른 흙막이벽체의 변위를 비교하여 지반굴착의 기하학적 형상의 차이와 관련된 영향성을 분석하였다. 흙막이벽체의 변위는 동일한 굴착 폭을 기준으로 굴착면의 길이 L이 증가함에 따라 증가하는 것으로 나타나며, 굴착단면치 중앙부에서 미장부재가 폐합되는 가설구조체계가 형성되는 모서리부로 갈수록 흙막이벽체와 띠장력재의 폐합에 치한 구속효과의 영향으로 인하여 감소하는 것을 알 수 있었다. 또한 흙막이벽체의 변형해석을 굴착평면의 형상을 고려하지 못하는 2차원 수치해석과 굴착평면의 형상을 고려할 수 있는 3차원 수치해석에 영향을 미치는 인자들 중 굴착면적비와 지반변형계수를 고려하여, 두 해석이 일치하는 상관관계를 흙막이벽체의 최대변위를 기준으로 2차원 수치해석 결과로부터 3차원 수치해석 결과가 도출할 수 있는 관계식을 제안하여 현장계측결과와 비교 하였다.

• Geomechanics and Engineering
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• 제35권6호
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• pp.617-626
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• 2023

In this study, three-dimensional numerical parametric study was conducted to explore deformation mechanisms of grouped piled-raft-foundation due to lateral load in clays. Effects of load intensity, loading angle, soil stiffness, pile diameter, pile spacing and pile length on foundation deformations were explored. It is found that the smallest and largest movements of pile foundation are induced when the loading angles are 0° and 30°~60°, respectively. By increasing loading angle from 0° to 30°~60°, the resultant horizontal movements and settlements increase by up to 20.0% and 57.1%, respectively. Since connection beams can substantially increase integrity of four piled raft foundation, resultant horizontal movements, settlements and bending moments induced in the piled raft foundation decrease by up to 54.0%, 8.8% and 46.3%, respectively. By increasing soil stiffness five times, resultant horizontal movements and settlements of pile foundation decrease by up to 61.7% and 13.0%, respectively. It is indicated that effects of connection beam and soil stiffness on settlements of pile foundation are relatively small. When pile diameter is less than 1.4 m, deformations of piled raft foundation decrease substantially as a reduction in the pile diameter. Two dimensional groups are proposed to develop calculation charts of horizontal movements and settlements of pile foundation. The proposed calculation charts can directly estimate movements of piled raft foundation under arbitrary loading, ground and pile conditions.

• Physical Therapy Rehabilitation Science
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• 제6권3호
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• pp.113-119
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• 2017

Objective: The objective of this study was to investigate the effects of Schroth's three-dimensional exercises in combination with respiratory muscle exercise (SERME) on Cobb's angle and functional movement screen (FMS). Design: Randomized controlled trial. Methods: Fifteen subjects with scoliosis were randomly assigned to two groups. Eight subjects were assigned to the experimental group and seven subjects were assigned to the control group. The experimental group underwent SERME using SpiroTiger (Idiag, Switzerland), while the control group performed only the Schroth's three-dimensional exercises (SE). Both groups performed exercises for one hour per day, three times a week for eight weeks. Cobb's angle, pulmonary function (forced vital capacity, forced expiratory volume at one second, and peak expiratory flow) and FMS were measured before and after the experiment. Results: After intervention, the SERME group showed a significant difference in Cobb's angle, FMS scores, and pulmonary function as compared to before intervention (p<0.05). In the SE group, there was a statistically significant difference in Cobb's angle, pulmonary function, and FMS scores compared to before intervention (p<0.05). The SERME group showed a significant difference in Cobb's angle and peak expiratory flow in pulmonary function compared to the SE group (p<0.05). Conclusions: The results suggest that SERME could be a more effective intervention for improvement of the Cobb's angle and pulmonary function for scoliosis patients.

• Computational Structural Engineering : An International Journal
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• 제1권1호
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• pp.1-9
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• 2001

Collapse behavior of Mission-Gothic Undercrossing under Northridge earthquake is studied by performing nonlinear time-history analysis and three-dimensional nonlinear finite element method for flared columns. Bridge structural model is characterized as three-dimensional with consideration of columns, superstructures, and abutment conditions. Three components of ground motion, corresponding to bridge's longitudinal, transverse, and vertical direction and their combinations are used to investigate bridge collapse. Studies indicate that bridge collapse is dominantly caused by transverse ground motion and the consideration of three-dimensional ground motion leads to a more accurate assessment. Failure mechanism of flared columns is analyzed applying nonlinear finite element method. Reduction of column capacity is observed due to orientation of flare. Further investigation demonstrates that the effects of flare play an important role in predicting of bridge failure mechanism. Suggestions are offered to improve the performance of bridges during severe earthquake.

• 동력기계공학회지
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• 제18권3호
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• pp.79-86
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• 2014

Mixed convective vortex flow in the three-dimensional rectangular channel filled with high viscous fluid(Pr=909) is investigated computationally under various operating conditions. The Reynolds number is varied from 0 to $5{\times}10^{-1}$, the Rayleigh number from $10^3$ to $5{\times}10^4$. The three-dimensional governing equations are discretized using the finite volume method. The effects of Reynolds number and Rayleigh number are presented and discussed. From a parametric study, it is found that vortex flow pattern of mixed convection in rectangular channels can be classified into three flow patterns basically, but the new vortex flow structures containing wave rolls are found, which are affected by Rayleigh number and Reynolds number. From this results, we can draw a flow regime map to delineate various vortex flow patterns in the high viscosity fluid mixed convective flow.

• 한국게임학회 논문지
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• 제10권1호
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• pp.135-146
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• 2010

방송과 영화 등에서의 영상 기술의 발전은 최근 3차원 입체 영상에 대한 관심을 증가시켜 왔다. 뿐만 아니라 2차원 영상의 한계로 인하여 3차원 콘텐츠에서의 입체 영상 표현 기술 개발이 시간이 지날수록 더욱 활발해지고 있다. 이는 단지 방송 분야에 국한되는 것이 아니라 의료, 교육 등 다양한 분야에서 폭넓게 접할 수 있도록 입체 영상 기술이 개발, 연구되고 있다. 하지만 입체감 표현에 있어 필요한 정교한 연출과 입체감 인지에 따른 피로감 발생 등의 이유로 예측 불허로 변화하는 게임과 같은 실시간 시스템에서 입체 영상 기술의 접목은 거의 이루어지지 않고 있다. 본 논문에서는 DirectX SDK 그래픽 파이프라인의 기하학적 구조를 바탕으로 입체감을 효율적으로 다룰 수 있고 상황에 따른 자동 시점 간격 조정을 통해 피로감을 해결하는 깊이감 조절 기법을 설계하였다. 이를 통해 입체 영상 기술이 접목된 게임 제작이 활발히 이루어질수 있는 새로운 대안을 제시해보고자 한다.

• 지질공학
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• 제31권1호
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• pp.43-53
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• 2021

본 연구에서는 부동침하 영향을 고려하여 지진 하중을 받는 1,300 ton 규모의 스테인리스 배수지 구조에 대한 3차원 유한요소 해석을 수행하였다. 1,000 ton 규모 이상의 대용량에 대한 지진하중은 한국표준 규격 규정으로부터 확장하여 산정하였다. 부동침하가 발생한 배수지는 특히 지진하중에 대하여 구조적 거동에 중요한 영향이 발생할 수 있다. 다양한 하중 조합에 대하여 정상상태의 경우, 침하가 고려된 경우, 그리고 수평으로 보강된 경우에 대한 응력 및 변위 분포의 변화를 도출하였다. 수치해석 결과로부터 부동침하가 발생된 배수지는 지진하중 조합에 대하여 최대 변위가 크게 증가하게 됨을 확인할 수 있었다.

• Geomechanics and Engineering
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• 제32권4호
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• pp.427-443
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• 2023

Across the globe, rapid urbanization demands the construction of basements for car parking and sub way station within the vicinity of high-rise buildings supported on piled raft foundations. As a consequence, ground movements caused by such excavations could interfere with the serviceability of the building and the piled raft as well. Hence, the prediction of the building responses to the adjacent excavations is of utmost importance. This study used three-dimensional numerical modelling to capture the effects of twin excavations (final depth of each excavation, H_e=24 m) on a 20-storey building resting on (4×4) piled raft. Because the considered structure, pile foundation, and soil deposit are three-dimensional in nature, the adopted three-dimensional numerical modelling can provide a more realistic simulation to capture responses of the system. The hypoplastic constitutive model was used to capture soil behaviour. The concrete damaged plasticity (CDP) model was used to capture the cracking behaviour in the concrete beams, columns and piles. The computed results revealed that the first excavation- induced substantial differential settlement (i.e., tilting) in the adjacent high-rise building while second excavation caused the building tilt back with smaller rate. As a result, the building remains tilted towards the first excavation with final value of tilting of 0.28%. Consequently, the most severe tensile cracking damage at the bottom of two middle columns. At the end of twin excavations, the building load resisted by the raft reduced to half of that the load before the excavations. The reduced load transferred to the piles resulting in increment of the axial load along the entire length of piles.