• 대한치과보철학회지
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• 제33권2호
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• pp.241-268
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• 1995

Splint therapy, the immobilization of teeth, has been done for patient's masticatory comforts and an adjunctive aid in periodontal therapy. Mandibular premolars are frequently splinted in many distal extension removable partial denture cases. But splinting is an extensive restoration that may not be conservative of tooth structure and may prove to be quite costly to the patient. The two dimensional finite element analysis method was used to determine the magnitude and mode of distribution of the stresses of the periodontal ligament and supporting alveolar bone when abutments with different periodontal supports were splinted and distal-extension removable partial denture was subjected to different loading schemes. The results were as follows : 1. When abutments were splinted, stresses moved from apico-distal to apico-mesial of terminal abutment on a vertical force and from disto-alveolar crest to apex on a distally directed force. But stresses were generally diminished on a mesially directed force. 2. As vertical bone loss was proceeding, most of stresses were transmitted to residual ridge and the rest of stresses were concentrated on apex of distal abutment. But these apical stresses were minimized when abutments were splinted. 3. As mesially inclined bone loss was proceeding, it seemed to be dangerous that many stresses were concentrated on the distal alveolar crest, especially in the distally directed load case. Abutments splinting decreased the alveolar crestal stresses but not enough. 4. For all vertical stresses were effectively decreased on splinting, stresses were concentrated as highly on apico-mesial area of distal abutment in distally directed load cases as the distal inclination of bone level was severe. 5. The directions and magnitudes of abutment movements were decreased with teeth splinting.

• Steel and Composite Structures
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• 제9권2호
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• pp.131-158
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• 2009

This paper presents a modelling technique for the nonlinear analysis of composite steel-concrete beams with partial shear interaction. It extends the applicability of two stiffness elements previously derived by the authors using the direct stiffness method, i.e. the 6DOF and the 8DOF elements, to account for material nonlinearities. The freedoms are the vertical displacement, the rotation and the slip at both ends for the 6DOF stiffness element, as well as the axial displacement at the level of the reference axis for the 8DOF stiffness element. The solution iterative scheme is based on the secant method, with the convergence criteria relying on the ratios of the Euclidean norms of both forces and displacements. The advantage of the approach is that the displacement and force fields of the stiffness elements are extremely rich as they correspond to those required by the analytical solution of the elastic partial interaction problem, thereby producing a robust numerical technique. Experimental results available in the literature are used to validate the finite element proposed in the paper. For this purpose, those reported by Chapman and Balakrishnan (1964), Fabbrocino et al. (1998, 1999) and Ansourian (1981) are utilised; these consist of six simply supported beams with a point load applied at mid-span inducing positive bending moment in the beams, three simply supported beams with a point load applied at mid-span inducing negative bending moment in the beams, and six two-span continuous composite beams respectively. Based on these comparisons, a preferred degree of discretisation suitable for the proposed modelling technique expressed as a function of the ratio between the element length and depth is proposed, as is the number of Gauss stations needed. This allows for accurate prediction of the nonlinear response of composite beams.

• Steel and Composite Structures
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• 제25권5호
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• pp.625-638
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• 2017

This paper presents a novel approach that describes the first-order (linear elastic) partial interaction analysis of members formed by multi-components based on the Generalised Beam Theory (GBT). The novelty relies on its ability to accurately model the partial interaction between the different components forming the cross-section in both longitudinal and transverse directions as well as to consider the cross-sectional deformability. The GBT deformations modes, that consist of the conventional, extensional and shear modes, are determined from the dynamic analyses of the cross-section represented by a planar frame. The partial interaction is specified at each connection interface between two adjacent elements by means of a shear deformable spring distributed along the length of the member. The ease of use of the model is outlined by an application performed on a multi-component member subjected to an eccentric load. The values calculated with an ABAQUS finite element model are used to validate the proposed method. The results of the numerical applications outline the influence of specifying different rigidities for the interface shear connection and in using different order of polynomials for the shape functions specified in the finite element cross-section analysis.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.861-866
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• 2004

A numerical flow analysis has been performed on the partial admission turbine of KARI turbopump to support the aerodynamic and structural dynamic assessments. The flow-field in a partial admission turbine is essentially three dimensional and unsteady because of a tip clearance and a finite number of nozzles. Therefore the mixing plane method is generally not appropriate. To avoid heavy computational load due to an unsteady three dimensional calculation, a frozen rotor method was implemented in steady calculation. It adopted a rotating frame in the grid block of a rotor blade by adding some source terms in governing equations. Its results were compared with a mixing plane method. The frozen rotor method can detect the variation of flow-field dependent upon the blade's circumferential position relative to the nozzle. It gives a idea of wake loss mechanism starting from the lip of a nozzle. This wake loss was assumed to be one of the most difficult issues in turbine designers. Thus, the frozen rotor approach has proven to be an efficient and robust tool in design of a partial admission turbine.

• 한국지진공학회논문집
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• 제24권1호
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• pp.39-47
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• 2020

Lightly reinforced concrete (RC) moment frames may suffer significant damage during large earthquake events. Most buildings with RC moment frames were designed without considering seismic loads. The load-displacement response of gravity load designed frames could be altered by masonry infill walls. The objective of this study is to investigate the load-displacement response of gravity load designed frames with masonry infill walls. For this purpose, three-story gravity load designed frames with masonry infill walls were considered. The masonry infilled RC frames demonstrated larger lateral strength and stiffness than bare RC frames, whereas their drift capacity was less than that of bare frames. A specimen with a partial-height infill wall showed the least drift capacity and energy dissipation capacity. This specimen failed in shear, whereas other specimens experienced a relatively ductile failure mode (flexure-shear failure).

• 한국멀티미디어학회논문지
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• 제7권8호
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• pp.1097-1106
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• 2004

전형적인 웹 클러스터 시스템은 여러 대의 실제서버와 클라이언트에 작업을 분배하는 가상서버로 구성된다. 본 논문에서는 고 가용성 웹 클러스터를 구성하기 위한 부하예측방식을 사용한 동적 작업 분배 방식을 제안하였다. 가상서버는 적절한 주기로 상태요청 메시지를 실제서버에 전송하여 부하 상태를 알아낸다. 하지만 작업분배 과정에서 실제의 부하상태의 변화를 정확히 알 수 없으므로 클라이언트의 요청에 대하여 실제서버의 부하상태를 예측하여 최소 부하상태 인 서버에 작업을 할당한다. 제안된 작업 분배방식은 실제서버의 부분적 고장과 무관하게 동작하며 부분적인 고장이 발생하여도 전체 시스템에 영향을 주지 않고 계속적인 서비스를 제공한다. 또한 다양한 성능평가를 수행하여 실제서버 확장에 따른 성능확장능력과 작업처리능력이 향상되었음을 보였다.

• Geomechanics and Engineering
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• 제6권2호
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• pp.195-211
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• 2014

Stone columns (or granular column) have been used to increase the load carrying capacity and accelerating consolidation of soft soil. Recently, the geosynthetic reinforced stone column technique has been developed to improve the load carrying capacity of the stone column. In addition, reinforcement prevents the lateral squeezing of stone in to surrounding soft soil, helps in easy formation of stone column, preserve frictional properties of aggregate and drainage function of the stone column. This paper investigates the improvement of load carrying capacity of isolated ordinary and geotextile reinforced sand column through field load tests. Tests were performed with different reinforcement stiffness, diameter of sand column and reinforcement length. The results of field load test indicated an improved load carrying capacity of geotextile reinforced sand column over ordinary sand column. The increase in load carrying capacity depends upon the sand column diameter, stiffness of reinforcement and reinforcement length. Also, the partial reinforcement length about two to four time's sand column diameter from the top of the column was found to significant effect on the performance of sand column.

• International Journal of Railway
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• 제8권1호
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• pp.5-9
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• 2015

Reliability based limit state design method is replacing traditional deterministic designs such as allowable stress design and/or ultimate strength design methods in world trends. European design code(Eurocode) has adopted limit state design, and Korea road bridge design standard has also recently been transferred to limit state design method. In this trend, Korea railroad design standard is also preparing for adopting the same design concept. While safety factors are determined empirically in traditional design, load combinations as well as load factors are determined by solving limit state equations. General partial safety factors are evaluated by using AFORM(Advanced First Order Reliability Method) in the reliability based limit state design method. In this study sensitivity analysis is carried out for a dead load factor and a live load factor. Relative precisions of the dead load and the live load factors are discussed prior to the AFORM analysis. Furthermore the sectional forces of design and the material quantities required by two different design methods are compared for a PSC box girder railway bridge.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제29회 춘계학술대회
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• pp.38-46
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• 1999

Numerical methods are procured for evaluating the contact stresses, the dissipation of friction energy density and the fatigue cracking emanated from the contact surface under the partial slip condition. A rounded punch is used for the indenter pressing and slipping on the elastic half plane. Plane strain condition is assumed for the present analysis. Several sample calculations are carried out to investigate the effect of the punch roundness, the shear load path, and the crack obliquity and closure on the failure. It is found that the present methods can be a useful tool for studying the physical failure of the of the contacting materials such as fretting wear and fretting fatigue cracking.

• 전자공학회논문지 IE
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• 제43권2호
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• pp.49-53
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• 2006

본 논문은 비디오 코딩에서 조절된 부분 영상 블럭의 차이값을 이용한 빠른 움직임 추정 알고리즘을 제안한다. 제안된 방법은 적은 계산량을 통하여 매우 정확한 움직임 벡터를 구할 수 있다. 실험을 통하여 제안된 방법은 전역 검색 방법(Full Search)가 매우 유사한 정확도를 보인 반면, 전역 검색 방법 보다 6에서 28배의 속도 향상을 보여주고 있다.