• 터널과지하공간
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• 제2권1호
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• pp.152-163
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• 1992

The study of rock mass behaviour through a numerical analysis is important for the design, construction and maintenance of large rock caverns. The objectives of the numerical analysis are to design reasonably and construct safely the underground structures, to maintain them soundly after construction and to extend them securely for a desired period of time. Methods of numerical analyses included in this case study are the finite element method, the boundary element method, and the distinct element method. The numerical models are purely elastic, elastoplastic, visco-elastic, visco-plastic, easto-visco-plastic and jointed-discontinuous materials. The results of this case study indicate that the rock mass behaviour could be predicted exactly through continuous comparisons of the numerical results with the in-situ measurements.

• 한국강구조학회 논문집
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• 제16권4호통권71호
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• pp.471-478
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• 2004

이 연구의 목적은 노출형 원형강관 주각이 중심축압축력을 받을 때 그 역학적 거동을 실험적으로 조사하고 탄성수치해석을 통하여 실험결과를 검토하고자 함에 있다. 실험에 앞서 AISC의 제안식 및 기존 연구에 관한 문헌조사를 실시하였다. 실험으로 중심축압축가력을 실시하였으며 베이스 플레이트 두께를 변수로 하여 두께 9mm부터 35mm까지의 9개의 시험체를 제작하였다. 실험결과는 하중 - 베이스 플레이트 수직변위관계, 하중 - 베이스 플레이트 변형도관계 등으로 정리하였다. 실험결과를 검토하기 위하여 탄성수치해석을 실시하였으며 탄성수치해석 프로그램으로는 Ansys version 6.1을 사용하였다. 실험 및 해석결과는 향후 실시할 비탄성해석결과와 함께 설계식 제안에 사용될 것이다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.1060-1065
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• 2002

In this paper, the numerical analysis of beam rest ing on hyperbolic Winkler elastic foundation by differential transformation is performed. Accordig to the change of parameter of hyperbolic Winkler elastic foundation, beam deformation is computed when the boundary conditions are clamped-clamped, pined-pined and clamped-free.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.402.2-402
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• 2002

In this paper, the numerical analysis of beam resting on hyperbolic Winkler elastic foundation by differential transformation is performed. Accordig to the change of parameter of hyperbolic Winkler elastic foundation, beam deformation is computed when the boundary conditions are clamped-clamped, pined-pined and clamped-free.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 봄 학술발표회 논문집
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• pp.11-18
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• 1999

For the proper design of a slender compression member, the exact determination of the elastic critical load is crucial, In the cases of non-prismatic compression members, the determinations of the elastic critical load cannot be usually expressed in closed forms. h this paper, the non-symmetrically tapered compression members with arbitrary boundary conditions me analysed by using the finite element method to determine the elastic critical load. The main parameters considered in the numerical analysis are the In Parameter, $\alpha$ and the sectional property parameter, m. To generaliza the unmerical analysis, of the computed results for each sectional parameter, m are presented in algebraic equations, which agrees fairy well with those by F.E.M in most cases.

• Geomechanics and Engineering
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• 제34권4호
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• pp.437-447
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• 2023

Inclined piles are commonly used in civil engineering constructions where significant lateral resistance is required. Many researchers proved their positive performance on the seismic behavior of the supported structure and the piles themselves. However, most of these numerical studies were done within the framework of linear elastic or elastoplastic soil behavior, neglecting therefore the soil non-linearity at low and moderate soil strains which is questionable and could be misleading in dynamic analysis. The main objective of this study is to examine the influence of the pile inclination on the seismic performance of the soil-pile-structure system when both the linear elastic and the nonlinear soil models are employed. Based on the comparative responses, the adequacy of the soil's linear elastic behavior will be therefore evaluated. The analysis is conducted by generating a three-dimensional finite difference model, where a full interaction between the soil, structure, and inclined piles is considered. The numerical survey proved that the pile inclination can have a significant impact on the internal forces generated by seismic activity, specifically on the bending moment and shear forces. The main disadvantages of using inclined piles in this system are the bending forces at the head and pile-to-head connection. It is crucial to account for soil nonlinearity to accurately assess the seismic response of the soil-pile-structure system.

• Journal of Theoretical and Applied Mechanics
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• 제3권1호
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• pp.16-33
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• 2002

A concept of hierarchical modeling, the newest modeling technology. has been introduced early In 1990. This nu technology has a goat potential to advance the capabilities of current computational mechanics. A first step to Implement this concept is to construct hierarchical models, a family of mathematical models which are sequentially connected by a key parameter of the problem under consideration and have different levels in modeling accuracy, and to investigate characteristics In their numerical simulation aspects. Among representative model problems to explore this concept are elastic structures such as beam-, arch-. plate- and shell-like structures because the mechanical behavior through the thickness can be approximated with sequential accuracy by varying the order of thickness polynomials in the displacement or stress fields. But, in the numerical analysis of hierarchical models, two kinds of errors prevail: the modeling error and the numerical approximation errors. To ensure numerical simulation quality, an accurate estimation of these two errors Is definitely essential. Here, a local a posteriori error estimator for elastic structures with thin domain such as plate- and shell-like structures Is derived using element residuals and flux balancing technique. This method guarantees upper bounds for the global error, and also provides accurate local error Indicators for two types of errors, in the energy norm. Comparing to the classical error estimators using flux averaging technique, this shows considerably reliable and accurate effectivity indices. To illustrate the theoretical results and to verify the validity of the proposed error estimator, representative numerical examples are provided.

• Structural Engineering and Mechanics
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• 제8권5호
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• pp.513-529
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• 1999

A concept of hierarchical modeling, the newest modeling technology, has been introduced in early 1990's. This new technology has a great potential to advance the capabilities of current computational mechanics. A first step to implement this concept is to construct hierarchical models, a family of mathematical models sequentially connected by a key parameter of the problem under consideration and have different levels in modeling accuracy, and to investigate characteristics in their numerical simulation aspects. Among representative model problems to explore this concept are elastic structures such as beam-, arch-, plate- and shell-like structures because the mechanical behavior through the thickness can be approximated with sequential accuracy by varying the order of thickness polynomials in the displacement or stress fields. But, in the numerical, analysis of hierarchical models, two kinds of errors prevail, the modeling error and the numerical approximation error. To ensure numerical simulation quality, an accurate estimation of these two errors is definitely essential. Here, a local a posteriori error estimator for elastic structures with thin domain such as plate- and shell-like structures is derived using the element residuals and the flux balancing technique. This method guarantees upper bounds for the global error, and also provides accurate local error indicators for two types of errors, in the energy norm. Compared to the classical error estimators using the flux averaging technique, this shows considerably reliable and accurate effectivity indices. To illustrate the theoretical results and to verify the validity of the proposed error estimator, representative numerical examples are provided.

• Tribology and Lubricants
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• 제12권3호
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• pp.63-71
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• 1996

The connecting rod bearing, which is subjected to periodical dynamic loading, is an impoRant component of the reciprocating engine. In the operation of this bearing, significant parameters are the oil film thickness and the film pressure. Peak film pressures of 20-30 MPa are not uncommon. So the elastic deformation of the bearing housing can have a significant effect on the bearing performance. In this study, a numerical analysis of connecting rod bearing is investigated. Elastic deformation of the bearing housing is considered in the analysis. Separate hydrodynamic and structural analysis are coupled through a direct iterative process. It is shown that as the result of the elastic deformation of the bearing housing, the eccentricity ratio is increased, and the minimum value of the minimum film thickness and the maximum value of the maximum film pressure are decreased. The variations of rotational speed and cylinder pressure affect the minimum film thickness and the maximum film pressure variations of the connecting rod bearing.

• 한국정밀공학회지
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• 제28권11호
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• pp.1288-1296
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• 2011

Effective elastic constants of bone-like biocomposites are investigated numerically. The bone-like materials are composed of strong layers and weak layers, and hierarchically structured. The unit cell model is employed to obtain the effective elastic constants. The effective anisotropic elastic constants of bone-like composites are obtained by using the potential energy method and finite element analysis. The effects of the Poisson's ratio, elastic modulus, hierarchical level, volume fraction and aspect ratio of the strong layer composed of the composites on the effective elastic constants are discussed.