• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.199-202
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• 2003

The dynamic characteristics of composite tool bars depend on the clamping conditions such as clamping force, stiffness and surface characteristics of clamping parts as well as the basic structures. Therefore, in this work, the effects of clamping part conditions on the dynamic characteristics of cantilever type composite machine tool structures with clamped joint were investigated because the cantilever type machine tool structures are ideal cases for composite application to increase the natural frequency and damping of structures. New design of the clamping part was developed in order to improve shear properties of the clamping part and dynamic characteristics of composite tool bars. From FE analysis and Impulse response tests, dynamic characteristics were obtained with respect to the clamping part conditions of the new design.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.183-188
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• 2002

Co-cured composite materials has its own characteristics, so its thermal expansion is different each other. The selection of tool material for co-cured composite part in high temperature more over $350^{circ}F$ and 50 Psi pressure have to consider part thermal expansion, size, shape, and economic aspect in production line. So it is important choose tooling material in manufacturing composite parts. We called the tool for airplane composite parts as BAJ (Bonding Assembly Jig). Composite parts are cured on the BAJ in autoclave. BAJ have to stable at high temperature over $350^{circ}F$ and 50 Psi pressure, Considering composite parts' dimensional tolerance compare to heat up in autoclave. This paper come from the results of the experiment at the composite parts production line and review other aircraft company's method for tooling This is for the engineer engaged in composite parts manufacturing.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.189-196
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• 2001

Machine tools of high-speed and high-precision are required for various fields of industry such as semiconductor, automobile, mold fabrication and so on. Light-weight machine tool structure is essential for reduction of production time through rapid transportation. Also, high damping capacity of the structure is required to obtain precise products without vibration during manufacturing. Composite materials have high potential for machine tool structures due to its high specific stiffness and good damping characteristics. In this study, the design and the manufacture of a hybrid machine tool structure using composite materials was attempted and the damping capacity was investigated experimentally.

• Steel and Composite Structures
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• 제18권5호
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• pp.1239-1258
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• 2015

This paper presents a master-slave constraint method, which may substitute the conventional transformed-section method, to account for the changes in cross-sectional properties of composite members during construction and to investigate the time-dependent performance of steel-concrete composite bridges. The time-dependent effects caused by creep and shrinkage of concrete are considered by combining the age-adjusted effective modulus method and finite element analysis. An efficient computational tool which runs in AutoCAD environment is developed to simulate the construction process of steel-concrete composite bridges. The major highlight of the developed tool consists in a very convenient and user-friendly interface integrated in AutoCAD environment. The accuracy of the proposed method is verified by comparing its results with those provided by using the transformed-section method. Furthermore, the computational efficiency of the developed tool is demonstrated by applying it to a steel-concrete composite bridge.

• Composites Research
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• 제33권5호
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• pp.262-267
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• 2020

고속 가공과 저중량 설계에 대한 수요가 증가함에 따라, 공작기계 주축의 진동 발생 가능성이 증가하고 있다. 또한 초정밀 가공에서 주축의 진동은 공작물 표면 형상에 큰 영향을 끼치게 된다. 다양한 가공 공정의 가공 정밀도를 향상시키기 위해, 공작기계 주축 진동 문제를 해결하여야 한다. 이 논문에서, 공작기계 주축의 진동 억제를 위해 TiC-SKH51 금속 기지 복합재가 사용되었다. TiC-SKH51 복합재의 동적 특성을 확인하기 위해 충격 망치 시험을 수행하였다. FEA의 모드 분석 결과와 충격 망치 시험 결과를 비교하여 FEA의 신뢰성을 확인한 후, 공작기계 주축 모델의 해석이 실행되었다. FEA 결과로부터 진동 발생 억제를 위해 TiC-SKH51 복합재를 적용한 공작기계 주축이 사용될 수 있음을 확인하였다.

• 대한기계학회논문집
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• 제14권1호
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• pp.37-42
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• 1990

본 연구에서는 수직 밀링에서 탄소섬유 에폭시 복합재료를 절삭할 경우 절삭 조건에 따른 공구마멸 형태를 조사하였으며, 여유면 마멸량을 측정하여 Taylor 지수를 구하였다. 또한 절삭조건 및 측정 방향에 따른 표면거칠기를 조사하여 탄소섬유 에 폭시 복합재료의 가공특성을 조사하였다.

• Composites Research
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• 제27권6호
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• pp.231-235
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• 2014

오토클레이브 성형은 성형제품의 품질은 우수하나 생산비용이 비싸다는 단점이 있다. 생산비용 중에서도 큰 비중을 차지하는 것이 성형툴의 제작공정이다. 따라서 본 연구에서는 생산비용 절감을 위한 선행 연구로서 성형툴의 재질 및 표면상태에 따라 L-shape 제품의 성형후 Spring-in을 Abaqus user subroutine을 이용하여 계산하였고, 열팽창계수와 마찰계수에 따른 결과를 나타내었다. 또한 성형툴 제작시 재질 및 표면상태의 기준점을 제시하여 생산비용을 줄이는데 기여하고자 한다.

• 한국CDE학회논문집
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• 제6권4호
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• pp.244-253
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• 2001

For more complete process planning, machining sequence determination is critical to attain machining economics. Although many studies have been conducted in recent years, most of them suggests the non-unique machining sequences. When the tool approach directions(TAD) are considered fur a feature, both machining time and number of setups can be reduced. Then, the unique machining sequence can be extracted from alternate(non-unique) sequences by minimizing the idle time between operations within a sequence. This study develops an algorithm to generate the best machining sequence for composite prismatic features in a vertical milling operation. The algorithm contains five steps to produce an unique sequence: a precedence relation matrix(PRM) development, tool approach direction determination, machining time calculation, alternate machining sequence generation, and finally, best machining sequence generation with idle times. As a result, the study shows that the algorithm is effective for a given composite feature and can be applicable fur other prismatic parts.

• 열처리공학회지
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• 제28권6호
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• pp.315-321
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• 2015

Friction stir processing (FSP) was applied to fabricate AZ31/CNT (Carbon Nano Tube) surface composite for improvement of surface hardness of AZ31 Mg-based alloy. The effects of traverse speed of rotating tool and volume fraction of CNT (i.e., groove depth of 3 mm and 4 mm) on the soundness and hardness of the composite layer were investigated. Multi-walled CNTs were fully filled in a machined groove and stirring tool was rotated at the speed of 1400 rpm. Only under the tool traverse speed of 25 mm/min for the specimen with a groove depth of 3 mm, surface composite layer with no defect was successfully produced. Increased hardness of about 35% was observed in the composite layer.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.223-226
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• 2002

To maximize the productivity in machining molds and dies, machine tools should operate at high speeds. However, the productivity of mold manufacturing has not increased significantly because CNC milling machines have massive slides, which do not allow rapid acceleration and deceleration during the frequent starts/stops encountered in machining molds and dies. This paper presents the use of composites for these slides to overcome this limitation. The vertical and horizontal slides of a large CNC machine were constructed by bonding high-modulus carbon-fiber epoxy composite sandwiches to welded steel structures using adhesives. These composite structures reduced the weight of the vertical and horizontal slides by 34% and 26%, respectively, and increased damping by 1.5 to 5.7 times without sacrificing the stiffness. Without much tuning, this machine had a positional accuracy of $\pm5\mu\textrm{m}$ per 300 m of the slide displacement.