• 지질공학
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• 제30권1호
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• pp.1-15
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• 2020

본 연구에서는 국내 지반굴착에 의한 지반거동 수치해석 평가 시 주로 사용되고 있는 Mohr-Coulomb 모델의 한계점을 분석하고, 실제 지반굴착 거동에 잘 부합되는 Hyperbolic 모델과 수치해석 결과를 비교하였다. 최근 국내에서 Mohr-Coulomb 모델 사용 시 지반굴착면이 실제보다 과다하게 융기되는 현상을 제어하기 위해서 특별한 경계조건을 임의대로 부과해서 해결하는 경향이 있다. 이러한 결과는 굴착면의 융기량의 크기만 제어할 뿐 지반거동이 실제와 왜곡되어 나타나는 문제점을 내포하고 있다. 본 연구에서 Hyperbolic 모델(Hardening Soil model)을 사용한 결과와 Mohr-Coulomb 모델을 사용한 결과를 비교하여, Hyperbolic 모델이 굴착 지반 융기량 및 실제 지반의 응력-변형거동에 더 잘 부합됨을 확인하였다. 지반굴착에 관한 수치해석 분석 시 Hyperbolic 모델을 사용하는 것이 실제 지반거동에 부합되는 결과를 얻을 수 있을 것으로 판단된다.

• 호남수학학술지
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• 제29권3호
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• pp.481-493
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• 2007

We will construct several types of semi-regular tilings of a hyperbolic unit disk model by defining geometric features of the definition of distance in a hyperbolic plane, area of triangle, and isometry of inversions. We researched the method of regular tilings and semi-regular tilings of hyperbolic unit disk model and wrote an semi-regular tiling construction algorithm using Cabri2 program and Cinderella program. Lastly, We want to make a product related to traditional heritage cultural patterns using Photoshop, so we'll model the advertising photos of cites; Seoul, Gwangju.

• 대한토목학회논문집
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• 제11권1호
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• pp.167-176
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• 1991

본 연구에서는 기존의 구성 모델인 hyperbolic모델과 Cam-clay모델을 적용하는 유한요소해석 프로그램을 개발하였다. hyperbolic모델에서는, 전단중의 체적 변형을 고려하는 새로운 모델을 제시하였으며, 또한 기초 아래 지반의 밀도 증가로 인한 매개 변수값의 변화를 고려하는 새로운 개념을 제안하고자 했다. 이와 더불어 보다 타당하다고 생각되는 계산 알고리즘을 제안하였다. 또한 Cam-clay모델을, 연구 사례가 많지 않은 모래질 흙에 적용함으로써 모래질 흙의 거동을 한계 상태 개념의 관점에서 분석해 보고자 하였다. 이를 위해 일반적인 압밀 배수 삼축 압축 시험과 모형 기초 재하 실험을 실시하였다. 그 결과, 본 논문에서 제안한 수정 hyperbolic모델을 사용함으로써 기존 모델보다, 기초에 작용하는 하중의 크기가 극한 지지력의 50%일때, 기초의 침하량 예측에 있어서 약 60% 정도, 결과의 향상을 기할 수 있었다. Cam-clay모델을 모래에 적용하는 경우에는 과압밀 효과를 고려할 수 있는 모델 및 변형률 연화를 고려할 수 있는 계산 알고리즘이 필요하다고 생각된다. 초기 포아송비의 크기는 Cam-clay모델의 경우 결과에 큰 영향을 미치지 않았으나, hyperbolic모델의 경우 결과에 큰 영향을 미치므로, 초기값의 선정에 신중하여야 함을 알 수 있다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.644-655
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• 2008

Conventional hyperbolic model does not satisfactorily predict the overall stress-strain behaviors of various geomaterials. Tatsuoka and Shibuya(1992) suggest the generalized hyperbolic equation(GHE) considering strain dependency and calculated performance is in good agreement with precise triaxial compression test results of stress-strain relations over wide range of strains before peak stress condition in some cases, but GHE model also does not satisfactorily predict stress-strain relations as strain goes on state of peak stress in most cases. For improve a weak point of the GHE, in this study, modified form of generalized hyperbolic equation (MGHE model) is proposed which can predict highly nonlinear stress-strain behavior for various geomaterials from small strain to peak stress condition.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1479-1482
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• 2003

The shock absorber is a part having a direct influence on the ride comfort, stability and dynamic load prediction of a vehicle. Thus, a rationally modeled shock absorber should be required in the dynamic analysis of vehicles. This thesis presents a modified model, based on Worden's hyperbolic tangent function, in order to fit experimental data on the velocity-damping force of a shock absorber. The hyperbolic tangent function correctly indicates the characteristics of a shock absorber. and has the advantage of containing physical causality. To evaluate the method, comparative evaluations of the linear model. the 5th polynomial model and Worden's model were carried out. The function presented in this paper is not only simple but also makes it possible to estimate the function coefficients easily and visually. In addition, it has the advantage of containing physical causality. Lastly, it effectively models the damping force of a shock absorber.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.805-812
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• 2003

The purpose of this study is to evaluate the behavior of a reinforced earth wall by modeling the properties of the interface between soil and reinforced elements as well as the non-linear stress-strain characteristics of soil. The effect of lateral earth pressures induced during construction is also included in the analyses. The interface element used to evaluate the relative movement of the interface between soil/reinforcement and soil/wall- facing has a zero thickness and essentially consists of normal and shear springs. The behavior of soil element is calculated based on the hyperbolic model. The computer program SSCOMPPC which includes the interface element, hyperbolic model and bi-linear model is applied in this study. From the analyses, it is showed that the locus of maximum tension were closed to the hi-linear failure line of theoretical analyses. The lateral displacement of SSCOMPPC is larger than that of the FLAC which adopts the elastic model. This means the analysis which is adopted the hyperbolic model and interface element induced more larger displacement.

• Geomechanics and Engineering
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• 제37권5호
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• pp.527-538
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• 2024

This study proposes a two-dimensional hyperbolic soil spring model for mat foundations in clays subjected to vertically uniform loads to simplify the complexity of three-dimensional finite element analysis on mat foundations. The solutions from three-dimensional finite element analysis were examined to determine the hyperbolic model parameters of the soil springs underneath the slab. Utilizing these model parameters, normalized functions across the middle section of the mat were obtained. The solutions from the proposed model, along with the approximate finite difference analysis of the mat in clays under vertical load, were found to be consistent with those from the three-dimensional finite element analysis. The authors conclude that the proposed method can serve as an alternative for the preliminary design of mat foundations.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제20회 춘계학술대회 논문집
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• pp.98-101
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• 2003

본 연구는 극초음속으로 비행하는 탄도발사체의 선두부분의 유동현상에 대해 기술하였다. 호주국립대학의 자유 피스톤 충격파 관 T3을 이용하여 수행한 Hyperbolic 선두형상의 실험 모델에 대해 이를 수치적으로 해석하였다 98%의 $N_2$와 2%의 $O_2$의 유동조건에 대해 전엔탈피 8MJ/kg에서의 실험결과를 수치결과와 비교를 하고, 2-temperature 모델링을 적용하여 1-temperature 모델링과의 차이를 확인하였다.

• Water Engineering Research
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• 제5권4호
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• pp.177-183
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• 2004

This paper introduces an eigenvalue method of transforming the hyperbolic partial differential equations of a particular unsteady friction water hammer model into characteristic form. This method is based on the solution of the corresponding one-dimensional Riemann problem that transforms hyperbolic quasi-linear equations into ordinary differential equations along the characteristic directions, which in this case arises as the eigenvalues of the system. A mathematical justification and generalization of the eigenvalues method is provided and this approach is compared to the traditional characteristic method.

• Current Optics and Photonics
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• 제1권4호
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• pp.336-343
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• 2017

A wide field-of-view (FOV) image contains more visual information than a conventional image. This study proposes a new type of hyperbolic mirror for wide FOV image acquisition. The proposed mirror consists of a hyperbolic cylindrical section and a bowl-shaped hyperbolic omnidirectional section. Using an imaging system with this mirror, it is possible to achieve a $213.8^{\circ}$ horizontal and a $126.94^{\circ}$ vertical maximum FOV. Parameters of each section of the mirror are designed to be continuous at the junction of the two parts, and the resultant image is seamless. The image-acquisition model is obtained using ray-tracing optics. To rectify the geometrical distortion of the original image due to the mirror, an image-restoration algorithm based on conformal projection is presented in this study. The performance of the proposed imaging system with the hyperbolic mirror and its image-restoration algorithm are verified by experiments.