• 한국정밀공학회지
• /
• 제32권11호
• /
• pp.969-976
• /
• 2015

In the present study, a numerical investigation of an insert injection molding process was carried out for the development of thermoplastic microfluidic chip plates with metal electrodes. Insert injection molding technology enables efficient realization of a plastic-metal hybrid structure and various efforts have been undertaken to produce novel components in several application fields. The microfluidic chip with metal inserts was proposed as a representative example and its molding process was analyzed. The important characteristics of the filling stage, such as the effects of filling time and thickness of the part cavity, were characterized. Furthermore, the detailed distributions of pressure and temperature at the end of the filling stage were investigated, revealing the significance of metal insert temperature.

• 자원환경지질
• /
• 제19권spc호
• /
• pp.97-102
• /
• 1986

Concepts on mineral association, mineral paragenesis, and mineralization stage relating to macrostructures of vein filling in ore veins are briefly discussed. As an example of plutonic ore vein, macrostructures of vein filling of plutonic tungsten-tin-copper vein at the Ohtani mine, Kyoto Prefecture, Japan, one of representatives of plutonic tungsten-tin vein related genetically to acidic magmatism of late Cretaceous in the Inner zone of Southwest Japan, are examined. Based on macrostructures of vein filling, three major mineralization stages, are distinguished by major tectonic breaks. Sequence of mineralization, characteristic features of each mineralization stage, and variations of filling temperature and salinity ranges of fluid inclusions in minerals from stage I to stage III are summarized.

• 한국지반환경공학회 논문집
• /
• 제15권12호
• /
• pp.97-107
• /
• 2014

현장에서 널리 활용하고 있는 침하예측기법으로는 Hyperbolic법, Hoshino법, Monden법 등이 있다. 이들 기존 침하예측법은 최종침하량 예측이 최종 성토단계가 완료된 이후 가능하다는 단점을 가지고 있다. 본 연구에서는 이와 같은 기존 예측법의 단점을 보완할 수 있는 새로운 침하량 예측법(SPSFC: Settlement Prediction for Staged Filling Construction)을 제안하였다. 이 방법은 연약지반에서 성토 완료 후뿐만 아니라, 초기 성토단계에서 단계성토별 시간-침하곡선을 예측할 수 있다. SPSFC법을 검증하기 위해 연약지반 개량을 위한 배수공법이 적용된 낙동강 하구 지역 두 개 현장에서 계측된 자료를 이용하여 기존 예측기법과 함께 SPSFC법으로 장래침하량을 예측하였다. 비교 결과, SPSFC법으로 예측된 침하량이 기존 예측법과 비교해서 신뢰성이 있음을 확인하였다. 또한 SPSFC법으로 초기 성토 단계에서 침하계측자료를 분석하여 예측에 필요한 지반상수를 구하고 이것을 이용하여 나머지 단계 성토 시 발생할 시간-침하량 곡선을 도시하였다. SPSFC법으로 예측된 침하량이 계측치와 잘 일치하는 것으로 나타나 SPSFC법으로 초기 성토단계의 침하계측 값만을 가지고 장래 침하량 예측이 가능함을 확인하였다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1995년도 춘계학술대회 논문집
• /
• pp.620-625
• /
• 1995

Finite element analysis tool was developed to analyze the casting process. Generally, casting processes consists of mold filling and solifification. In order to investigate the effects of process variables and to predict the defects, both filling and solidiffication process were simulated simultaneously. At filling process, especiallywe consider thermal coupling to investigate thermal history of material during the filling stage. And thermal condition at the final stage of filling is used as the initial conditions in a solidification process for the exact simulation of the actual casting processes. At mold filling process, Lagrangian-type finite element method with automatic remashing scheme was used to find the material flow. To avoid numerical instability in low viscous fluid, a perturbation method with artificial viscosity is adopted. At solififfication process, enthalpy-based finite element method was used to solve the heat transfer problem with phase change. And elastic stress analysis has been performed to predict the thermal residual stress. Through the FE analysis, solidiffication time, position of solidus line, liquidus line and thermal residual stress are studied. Finite element tools developed in this study will be used process design of casting process and maybe basic structure for total CAE system of castigs which will be constructed afterward.

• 한국산학기술학회논문지
• /
• 제18권12호
• /
• pp.57-64
• /
• 2017

오늘날 EU환경규제로 포장용 완충재로 사용되는 EPS(스티로폼) 대체용 공기 충진 완충재는 출시 이후 점진적으로 시장이 확대되는 포장업계 블루칩이다. 공기충진형 완충재는 뛰어난 완충능력과 친환경성으로 EPS를 대체하여 빠르게 시장을 확장하고 있다. 기존 공기 충진 완충재에 대비하여 원료절감과 공정향상, 직관적 미관 향상을 모두 충족하는 새로운 선택 충진형 공기 충진재 제조기술이다. 본 연구는 다단 에어셀 충진 밸브성형기술은 선택충전 기술을 바탕으로, 밸브형성 구조기술을 적용하여 선택적으로 다양한 형태로 충진이 가능한 기술이다. 다단 에어셀 충진 밸브성형기술의 구조도는 밸브단이 구분된 제1주입필름, 밸브필름, 제2주입필름 등 3겹의 필름을 적층하여 복수의 주입구를 형성한 기술이다. 기존의 기술은 연결된 다수의 공기주머니에 공기를 주입하기 위한 별도의 외부 공기주입로가 필수적으로 구성되어야 하나, 본 연구는 공기 주머니의 내부에 외부 공기주입로가 형성되어 공기를 주입하기 위한 외부 공기주입로가 외견상 없어짐으로써 그에 따른 원재료 및 공정이 감소하고, 공기가 주입되어 원형 튜브로 팽창하는 과정에서 단면의 길이가 63~66%로 축소되는 공기주머니와 다르게 공기주입 후 내부 공기가 배출되고 단면이 원래의 길이를 유지하여 불필요하게 접힌 채 붙어 있는 외부 공기주입로를 내부에 일체화 하여 완충재의 미관이 향상되는 기술적 특징과 다수의 연속된 공기주머니에 선택적으로 공기를 충전할 수 있는 선택충전에 관한 것으로 기존 기술대비 뛰어난 차별성을 갖는 스마트한 공기충전형 완충재 제조 기술이다.

• Geomechanics and Engineering
• /
• 제36권1호
• /
• pp.27-37
• /
• 2024

The roof-filling body system stability plays a key role in gob-side entry retained (GER). Taking the GER of the 1103 belt transportation roadway in Heilong Coal Mine as engineering background, stability analysis of roof-filling body system was conducted based on the cusp catastrophe theory. Theoretical results showed that the current design parameters of 1103 belt transportation roadway could ensure the roof-filling body system stable during the resistance-increasing support stage of the filling body and the stable support stage of the filling body. Moreover, a verified global numerical model in FLAC3D was established to analyze the failure characteristics including surrounding rock deformation, stress distribution, and plastic zone. Numerical simulation indicated that the width-height ratio of the filling body had a great influence on the stability of the roof-filling body system. When the width-height ratio was greater than 0.62, with the decrease of the width-height ratio, the peak stress of the filling body gradually decreased; when the width-height ratio was greater than 0.92, as the distance to the roadway increased, the roof stress increased and then decreased. The theoretical analysis and numerical simulation findings in this study provide a new research method to analyze the stability of the roof-filling body system in GER.

• 한국정밀공학회지
• /
• 제13권3호
• /
• pp.110-122
• /
• 1996

Finite element analysis tool was developed to analyze the casting process. Generally, casting process consists of mold filling and solidification. Both filling and solidication process were simulated simultaneously to investigate the effects of process variables and to predict the defect. At filling process, thermal coupling was especially considered to investigate thermal history of material during the filling stage. And thermal condition at the final stage of filling is used as the initial conditions in a solidification process for the exact simullation of the actual casting processes. At mold filling process, Lagragian-type finite element method with automatic remeshing scheme was used to find the material flow. A perturbation method with artificial viscosity is adopted to avoid numerical instability in low viscous fluid. At solidification process, enthalpy-based finite element method was used to solove the heat transfer problem with phase change. And elastic stress analysis has been performed to predict the thermal residual stress. Through the FE analysis, solidification time, position of solidus line, liquidus line and thermal residual stress are found. Through the study, the importance of combined analysis has been emphasized. Finite element tools developed in this study will be used process design of casting process and may be basic structure for total CAE system of castings which will be constructed afterward.

• Journal of Welding and Joining
• /
• 제18권2호
• /
• pp.191-191
• /
• 2000

The mechanism of the blowhole and the pit formation in lap-jointed fillet CO₂ arc welds of Zn-coated steel sheet was established by the direct observation of the gas behavior in the molten pool with the high speed camera system. Main conclusions obtained are as follows1) Some blowholes were formed by incomplete back-filling to the pits at the last stage of the solidification. This type of blowhole was formed through four stages of gas in the molten pool, incubation, explosion, back-filling and completion of back-filling stage.2) Most of the pits was back-filled at the last stage of their formation. (Received September 27, 1999)

• Journal of Welding and Joining
• /
• 제18권2호
• /
• pp.64-68
• /
• 2000

The mechanism of the blowhole and the pit formation in lap-jointed fillet Co₂arc welds of Zn-coated steel sheet was established by the direct observation of the gas behavior in the molten pool with the high speed camera system. Main conclusions obtained are as follows: 1) Some blowholes were formed by incomplete back-filling to the pits at the last stage of the solidification. This type of blowhole was formed through four stages of gas in the molten pool, incubation, explosion, back-filling and completion of back-filling stage. 2) Most of the pits was back-filled at the last stage of their formation.

• 지질공학
• /
• 제29권4호
• /
• pp.393-403
• /
• 2019

취수보의 저류성능은 유량과 수심의 관계로 평가될 수 있다. 돌망태 취수보의 유량과 수심의 관계는 채움재의 물리적 특성에 따라 달라진다. 본 연구에서는 인공함양 원수확보를 위한 돌망태 취수보의 저류성능을 평가하는데 활용할 기존의 방류량 산출식들을 검토하였다. 채움재의 물리적 특성을 실험변수들과 관계식으로 표현한 기존의 방류량 산출식은 유량과 수심의 관계를 잘 표현하였다. 또한 채움재의 평균입경은 수심확보와 간접취수에 영향을 미치기 때문에 저류성능 뿐 아니라 취수성능에도 중요한 인자임을 알 수 있었다.