• Journal of the Korean Society of Safety
• /
• v.31 no.6
• /
• pp.1-5
• /
• 2016

A bicycle is one of the most popular sporting goods in view of a sport activity and a human health. Metallic materials such as steel, aluminum, etc. were mainly used to the bicycle fork in the past. Nowadays, the carbon fiber reinforced composite materials are widely used to the manufacturing of a bicycle fork to reduce the weight and to increase the efficiency. Safety is a most important design parameter of a bicycle fork even if the weight and cost reduction are important. Bicycle failure may happen at the critical spot of a bicycle fork and cause the accident. In this paper, the composite bicycle fork will be analyzed to secure the safety and detect a critical spot by using the finite element method with Tsai-Wu failure criterion. The stress data were obtained for the laminated composites with various number of plies and fiber orientation under the bending load. Thus, design concept of a bicycle fork was proposed to secure the safety of a bicycle. The finite element analysis results show that the connection area between a steer tube and a fork blade is critical spot, and 75 or more layers of 0 degree are needed to secure the safety of a bicycle fork.

• Journal of Power Electronics
• /
• v.8 no.2
• /
• pp.109-120
• /
• 2008

In this paper, a novel delta/double-fork transformer based 18-pulse full-wave AC-DC converter is designed, modeled, simulated and developed to feed isolated DC varying loads. The proposed AC-DC converter is used for low voltage and large current DC loads in applications such as electrowinning, where isolation is required mainly for stepping down the supply voltage. The proposed converter improves power quality at AC mains and meets IEEE-519 standard requirements at varying loads.

• 전기의세계
• /
• v.13 no.2
• /
• pp.1-4
• /
• 1964

Phase transformation is used to change some phase from phase in A.C. system. We have been used Scott or Fork connection in phase transformation the otherwise phase transformation was constructed from M-G set. From this M-G set, we could make phase shift facilities by mannual. Now, I can derive more easy phase transformation from taking another method. I believe this new phase transformation method in the first thing in the world. And so, I am going to explain about phase transformer construction process. The first, we could devide into equal part of core around the iron core as to be same size. The second, you will make primary and secondary winding on the core. The third, when you will supplied three phase A.C. at the terminal of primary winding you can get e.m.f. inducing of some phase at secondary. And so, we could make phase change from some phase A.C. We can apply this principle in many fields, i.e., freequency changer, phase leader of no use condenser, voltage regulator in keeping balance, and D.C. generator. And more, I will introduce in details concerning main pinciple and theory through following chapter.

• Journal of the Korean Institute of Rural Architecture
• /
• v.5 no.2
• /
• pp.20-32
• /
• 2003

In this study, I grasped the actual conditions of folk exhibition hall in Chungbuk area. From this data I researched basically as the fundamental role of regional museum, eco-museum core center facilities, the connection with islanded and various inheritances, and central facilities whole area to the museum. And I could get following conclusion. First, on the studied result of folk exhibition hall in chungbuk area, it is not enough the activity of unearthing, collection, study etc. that is basic activity of the museum because the museum just permanently displayed historical contents of the area and simple life folk data. Second, add to existent museum concept and have to widen viewpoint to the museum which whole area is no roof, and utilize folk exhibition hall as the central facilities. Specially, there are a lot of difficulties to communicate information to visitors because of the absence of cultural heritance exponent. So a plan that local resident participate actively in museum activity may have to be considered. Third, the concept of inheritance limited in historical culture of area has to be widening by nature and industry etc. And we should keep up study that is the linked plan to scattered conservation remains, inheritance and tourist place in area.