성형 공정을 수정한 SCM435H 볼트의 초기 2단계까지의 공정 해석

안교철(Ahn, Kyo-Chul),최취경(Choi, Chui-Kyung) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.11

본 연구에서는 볼트의 원활한 성형이 이루어지도록 볼트의 성형 공정 중 2단계에서 시행하던 압출공정을 4 단계로 옮기고 2단계와 3단계에서는 볼트 머리부 성형만 이루어지도록 공정을 조정하여 해석하였다. 그 결과 약간의 수정으로 원활한 성형이 이루어 졌으며 접촉압력은 수정 전보다 1단계에서는 감소하고 2단계에서는 증가하였으며, 최 대유효응력, 유효변형율, 성형력은 수정전보다 1, 2단계에서 모두 증가함을 알 수 있었다. For a easier bolt molding, an extrusion process, the 2nd step of the molding process, was moved to step 4, and the bolt head section was exclusively molded in steps 2 and 3. As a result, the molding process was made easier thanks to the minor modification, and the contact pressure decreased in step 1 and increased in step 2 over its earlier intensity. Also, the maximum effective stress, effective strain, and molding force were all increased in both steps 1 and 2.

유한요소법을 이용한 SCM435 Bolt의 성형 공정에 관한 해석 및 공정 개선 방안

안교철(Ahn, Kyo-Chul),최취경(Choi, Chui-Kyung) 한국산학기술학회 2012 한국산학기술학회논문지 Vol.13 No.11

볼트의 제작 공정은 연속적인 단조 작업에 의해서 완성되는데 각 공정의 기술적, 경제적인 성공은 적절한 공정설계와 각 작업에 필요한 금형 설계에서 좌우된다. 본 연구에서는 다단 공정에 의해서 이루어지는 SCM435 볼 트의 성형과정 중에서 1, 2단계의 성형을 유한요소법을 이용하여 해석하여 합리적인 공정이 이루어지도록 개선 방향 을 제시하고자 하며 유한요소법을 이용하여 해석한 1, 2단계의 공정은 축대칭이 성립되므로 소재의 변형 형상이 공 정에서 기대했던 치수를 만족할 수 있었으며 소재에 형성된 단류선이 전 공정을 통하여 부드럽게 연속적으로 형성됨 을 알 수 있었으므로 소재의 성형 뿐 아니라 내부의 결함도 없을 것으로 예상되었다. A bolt manufacturing process is completed with continuous forging. Technical and economical success of each process will depend on the appropriate process design and metal mold design for each procedure. This study aims to analyze the moldings of first and second steps among the multi-step molding processes of SCM435 bolt by use of the finite element method in order to achieve the reasonable process. Since the processes of first and second steps analyzed by use of the finite element method consist of axial symmetry, the transformed configuration of material satisfy the dimensions expected in process. In addition, the uniflow line formed in material becomes smooth and consistent over the entire process. Therefore neither molding of material nor inherent defect is expected.

강수량 변화에 따른 중수도설비를 이용한 절수대책

안교철 ( Kyo Chul Ahn ) 대한설비관리학회 2012 대한설비관리학회지 Vol.17 No.2

In this study, we intend to propose the policy to supply water, and its problems and the measures for utilizing the wastewater reclamation and reusing system with analyzing the amount of the rainwater that can be secured in recent. Seen with the conditions of Korea, which has been appointed as a country with lack of water by U·N, it is necessary to prepare measures for saving water by using the rainwater without any introduction of additional equipment or systems for the preparation of the unexpected change of precipitation amount and heavy rain in the near future. In addition, to expand the supply of the wastewater reclamation and reusing system, some strong national policies should be taken. As to the technical problems, the existing sewage treatment method should be promptly converted to the advanced treatment method that has been already applied in the advanced countries. As prospective tasks, the standards of calculating the pipe diameter, which has been previously used, should be reviewed again to prwpare the amount of precipitation that has dramatically changed due to the climate change.

에너지 절감을 고려한 열쾌적성,실내공기질 컨트롤러 개발

안교철 ( Kyo Chul Ahn ) 대한설비관리학회 2011 대한설비관리학회지 Vol.16 No.4

It was developed temperature comfortable indoor air quality controller controlled ventilation according to cooling load, heating load and CO2 concentration in the time of cooling and heating of building. The application of controller was programed by neuron C, in order to increase field tailorability of the controller was manufactured to module type that can be applied to RS422, power line and Zigbee com- munication without reference to the filed network environment. The controller reduced waste energy by controlling ventilation and analyzing temperature, humidity and CO2 concentration, the communication traffic was decreased by multicast type of the controller.

배압에 따른 에어커튼형 냉동용 전시케이스의 성능변화

성순경(Sun-Kyung Sung),안교철(Kyo-Chul Ahn) 대한설비공학회 2013 설비공학 논문집 Vol.25 No.11

Vertical open display cases are widely used in shopping malls, supermarkets, or retail stores to sell frozen and refrigerated products. Open display cases use air curtains to maintain a reasonable temperature within the storage space, prevent insects from breaking in, and reduce energy usage. In this research, computational fluid dynamics was used to find the optimal condition for reducing energy by considering various conditions such as discharge speed or temperature of air curtains. Results of the study showed that the amount of energy consumed in the display cabinet is influenced by the discharge speed and temperature of the slots installed on the upper area and the amount of air supplied to the storage area inside the shelf. This shows that the amount of discharged air supplied from the storage area influences the formation of air curtain and also the amount of energy consumption. As a result of this study, we learned that the amount of energy used can be reduced by increasing the amount of discharged air within the storage area and enhancing back pressure.

전력선 통신에 의한 공기조화설비 제어네트워크 구축

김명호(Kim, Myungho),안교철(Ahn, Kyochol) 한국정보전자통신기술학회 2008 한국정보전자통신기술학회논문지 Vol.1 No.2

로컬 레벨의 표준화 및 시스템간의 상호운용성을 높이기 위하여 공기조화설비 제어 계통도를 지하층(8포인트)과 기준층(15포인트)으로 구분하여 설계하고 전력선통신으로 제어 네트워크를 구축하였다. 공기조화 시스템의 각 디바이스는 개방형 프로토콜인 뉴런 C로 프로그램 하였다. 연구 결과 프로토콜로 각 디바이스들의 자율분산제어가 가능하게 되었고 통신선의 길이와 회선수를 감소시킬 수 있었다. In order to enhance standardization and interoperability of local level systems, AHU control network was designed with basement(8 point) and basis story(15 point) and then the network was constructed by power line communication. Each devices of AHU system were programed with neuron C of as an open protocol. As a result of a study, each devices of the network were controlled with self dispersion process by protocol and wiring could be reduced by power line communication.

TS볼트체결에서 체결력 , 토오크계수 및 품질관리에 관한 연구

손승요(Seung Yo Son),신근하(Keun Ha Shin),최돈흥(Don Heung Choi),조인습(In Sub Cho),안교철(Kyo Chul Ahn) 한국강구조학회 1994 韓國鋼構造學會誌 Vol.6 No.3

TS(abridged from Torque-Shear) bolts are originaly developed for the purpose of quality assurance in clamping force by means of fracture mechanism due to the stress concentration around the V-type notch at the bolt tip. In the control of tightening a bolt, torque factor as well as geometries of the notch (diameter, angle and roundness) are of prime importance to assure the quality of the joint performance in a structure. Some theoretical aspects of fastening torque and clamping force in a TS bolt are examined with focus on the friction coefficients. A simple relationship between face friction coefficient and thread friction one is derived, and numerical calculations and plots based on the experimental data are presented, which may be used as a complementary guide in a situation to cope with torque factor degradation. It is found that the interaction between friction torque on the thread and the tensile force developed in a bolt leads to an elliptic stress space. The upper limit of thread friction coefficient μ_s and the lower limit of face friction coefficient μ_w are derived and plotted against the axial force ratio.

급수관에서 관재에 따른 부식특성과 미생물 재성장 고찰

김태현 ( Tae Hyun Kim ),이윤진 ( Yoon Jin Lee ),이환 ( Hwan Lee ),이철효 ( Cheol Hyo Lee ),안교철 ( Kyo Chul Ahn ),이우식 ( Woo Sik Lee ) 한국환경과학회 2007 한국환경과학회지 Vol.16 No.1

급수배관의 압력분포와 감압 방법

안교철 경원전문대학 2001 論文集 Vol.23 No.-

The pressure distribution is very important at down stairs in multistory building. Therefore, the method of pressure reducing is essential to cold water piping system. This paper describe pressure distribution and pressure reducing method in cold water piping system of multistory building.