• 소성∙가공
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• 제31권6호
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• pp.384-393
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• 2022

The flow forming process consists of a split process, a divide process, and a forming process. The split process is a forming process in which rollers radially permeate a simple disc-shaped forging material and split it in both directions to form a top-bottom bidirectional cup. It is advantageous for post-processing to deepen the forming depth in the split process but this characteristic causes the failure near the edge of the mandrel during the actual process. The split process was analyzed using Rigid Plastic FEM, and the stress analysis of the mandrel was conducted to find the cause of the failure. It was found that the failure occurred due to fatigue accumulation damage caused by repeated residual stress.

• 설비공학논문집
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• 제12권1호
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• pp.67-74
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• 2000

One of the important application of a contact melting process is a latent thermal energy storage owing to its high heat flux. In some previous works, the split fins have been employed in order to enhance the melting speed. In the present work, the close contact melting was experimentally investigated using an ice as specimen for both split and non-split fins. It was shown that the contact melting by split fins increases the melting rate compared to that of non-split ones.

• 경영정보학연구
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• 제2권1호
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• pp.151-160
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• 2000

• 한국기계가공학회지
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• 제19권5호
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• pp.91-97
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• 2020

A split-die design for the cold forging of symmetric parts such as those having a hexagonal cross-section is presented in this paper. Parts with a hexagonal cross-section, such as bolt heads and nuts, should be forged with a die that has a hexagonal-shaped hole. A split type die is required to mitigate the buildup of stress concentrations located at the corners of the hexagonal hole. Generally, the insert of a hexagonal die is made by cutting each corner of a cylinder using a hexagonal hole and then combined with the die and shrink-fitted. However, split dies face problems when extruding material at the corners of the hexagonal split die. To address this problem, two types of split dies were evaluated: rounded hexagonal dies and angular hexagonal dies. The effects of the pre-stress ring on the dies were compared and analyzed and results show that using the angular split hexagonal die can extend the lifetime of forging dies.

• International Journal of Precision Engineering and Manufacturing
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• 제7권1호
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• pp.3-8
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• 2006

This paper deals with an automated computer-aided process planning and die design system by which designer can determine operation sequences even if they have a little experience in process planning and die design for axisymmetric products. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. The system can provide a flexible process based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution on the level of the required forming loads by controlling the forming ratios. Especially in die design module optimal design technique and horizontal split of die insert were investigated for determining appropriate dimensions of components of multi-former die set. Results obtained, using the modules, enable the design and manufacture of a die set for a multi-former to be more efficiently performed.

• International Journal of Air-Conditioning and Refrigeration
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• 제9권2호
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• pp.1-7
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• 2001

One of the important applications of a contact melting process is a latent thermal energy storage system owing to its high heat flux and small temperature variation. In some previous works, the split fins have been employed in order to enhance the melting rate. In the present work, the direct contact melting was experimentally investigated using an ice as specimen for both split and non-split fins. It was shown that the contact melting by split fins increases the melting rate compared to that of non-split ones.

• 전자공학회논문지D
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• 제35D권3호
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• pp.28-38
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• 1998

In our paper is reported a new 3D(dimensional) trajectory split approach with greatly improved efficiency for the Monte Carlo simulation of the 3D profiles of implanted ionand point defect concentrations in single-crystal silicon. This approach has been successfully implemented in our TRICSI Monte Carlo code. Combined with the previously developed model for damage accumalation in our TRICSI code, this model allows phasically based dynamic simulation of 3D profiles over an subsequent process simulation such as diffusion modeling and simulation. A typical time saving of over 10 timeshas been achieved for 3D simulation. Our method ensures much better region aground the implanted area. For 1-D simulation, the optimized condition for trajectory split has set to 3,000 pseudoparticles with 2 split branches.

• Journal of Periodontal and Implant Science
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• 제10권1호
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• pp.43.2-43.2
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• 1980

• Composites Research
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• 제14권2호
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• pp.8-12
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• 2001

필라멘트 와인딩 공법(filament winding process)은 회전하는 맨드렐에 로빙(roving)형태의 연속섬유를 감는 비교적 간단한 공정이다. 이것은 저장탱크, 화학용 파이프, 그리고 다른 산업에 사용되는 안정적이고 다양한 공법이다. 본 연구에서는 split disk test 치구와 dress disk test 치구에 의한 필라멘트 와인딩 링 시편의 인장강도 값을 실험에서 얻어진 결과와 혼합법칙에 의해 얻어진 이론적인 값을 비교하였다. 이 논문의 목적은 필라멘트 와인딩 구조물의 인장 특성 평가에 대한 적합한 시험법을 제안하고 있는 것이다. dress disk test 치구로 시험한 링 시험편의 인장강도는 split disk test 치구의 모서리 부분에서 발생하는 응력집중 때문에 split disk test의 시험 결과보다 이론적인 인장강도 간에 잘 근절함을 보여준다. 이 실험 결과 시험 치구의 기하학적 형상과 섬유의 연속성, 섬유 장력 그리고 시험편의 응력 집중에 영향은 받음을 알 수 있었다.

• 한국CDE학회논문집
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• 제1권3호
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• pp.224-233
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• 1996

An automatic mesh generation scheme with triangular finite elements on three-dimensional surfaces has been developed. The surface triangulation process is performed as follows. To begin, surfaces with key nodes are transformed to two-dimensional planes and the meshes with triangular elements are constructed in these planes. Finally, the constructed meshes are transformed back to the original 3D surfaces. For the mesh generation, an irregular mesh generation scheme is employed in which local mesh densities are assigned by the user along the boundaries of the analysis domain. For this purpose a looping algorithm combined with an advancing front technique using basic operators has been developed, in which the loops are recursively subdivided into subloops with the use of the best split lines and then the basic operators generate elements. Using the split lines, the original boundaries are split recursively until each loop contains a certain number of key nodes, and then using the basic operators such as type-1 and type-2, one or two triangular elements are generated at each operation. After the triangulation process has been completed for each meshing domain, the resulting meshes are finally improved by smoothing process. Sample meshes are presented to demonstrate the versatility of the algorithm.