• Ocean Systems Engineering
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• 제12권4호
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• pp.439-459
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• 2022

This paper describes experimental studies of impact pressure generated by breaking regular waves in shallow water on a vertical cylinder. Experimental work was carried out in a shallow water flume using a 1:30 - scale model of a vertical rigid circular hollow cylinder with a diameter 0.2 m. This represents a monopile for shallow water offshore wind turbines, subjected to depth induced breaking regular waves of frequencies of 0.8 Hz. The experimental setup included a 1 in 10 sloping bed followed by horizontal bed with a constant 0.8 m water depth. To determine the breaking characteristics, plunging breaking waves were generated. Free surface elevations were recorded at different locations between the wave paddle to the cylinder. Wave impact pressures on the cylinder at a number of elevations along its height were measured under breaking regular waves. The depth-induced wave breaking characteristics, impact pressures, and wave run-up during impact for various cylinder locations are presented and discussed.

• 한국생산제조학회지
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• 제8권4호
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• pp.45-51
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• 1999

In this study to assess chip breaking characteristics of cold-drawn free machining steels a newly developed non-dimensional parameter chip breaking index CB has been adopted. And for comparison with free machining steels chip breaking characteristics of conventional carbon steels were investigated. Properly controlled chips were produced with the CB value of 0.05-0.2 regardless of steel types. In case of cold-drawn free machining steels however cycle times of chip breaking are relatively shorter than those of conventional steels. And properly controlled chips were obtained from wider range of feed rate.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 춘계학술대회 논문집
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• pp.21-26
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• 1999

In this study, to assess chip breaking characteristics of cold-drawn free machining steels, a newly developed non-dimensional parameter, chip breaking index, C/sub B/ has been adopted. And for comparison with free machining steels, chip breaking characteristics of conventional carbon steels were investigated. Properly controlled chips were produced with the C/sub B/ value of 0.05∼0.2, regardless of steel types. In case of cold-drawn free machining steels, however, cycle times of chip breaking are relatively shorter than those of conventional steels. And properly controlled chips were obtained from wider range of feed rate.

• 한국기계가공학회지
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• 제3권2호
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• pp.25-31
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• 2004

Machinability in metal cutting processes depends on cutting input conditions such as cutting velocity, feed rate, depth of cut, types of work material and tool shape factors. In this study, to assess chip breaking characteristics of a turning process, an equivalent oblique cutting system to this has been established. And the equivalent effective rake angle was determined using side rake angle, back rake angle and side cutting edge angle of the tool. A non-dimensional parameter, Chip breaking index(CB), was used to assess Chip breaking characteristics of chip in conjunction with the equivalent effective rake angle. In case of positive rake angles of the equivalent effective rake, the back rake angle has little effect on the chip breaking characteristics however, in case of negative ones, the side rake angle has some effect on Chip breaking characteristics.

• 한국해양환경ㆍ에너지학회지
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• 제5권1호
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• pp.11-18
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• 2002

방향 및 주파수 성분을 포함하는 파랑집중에 의해 다방향 쇄파를 생성하였으며, 등기울기 및 등진폭 스펙트럼 모델을 적용하였다. 생성된 다방향 쇄파는 초기쇄파, 단일쇄파 다중쇄파로 구분된다. 다방향 쇄파의 특성을 파정 기울기 및 비대칭성으로 정의되는 파형인자들의 함수로 고찰하였다. 또한 파랑집중의 효율성 관점에서 쇄파 파랑특성의 전개를 분석하였다. 파정 전면 기울기 및 연직 비대칭성은 쇄파과정에 영향을 미치는 중요한 인자이나, 파정후면 기울기 및 수평 비대칭성은 쇄파 과정에서 거의 상수 값을 갖는다. 방향 성분의 중첩은 파랑집중의 효율성을 크게 강화하며, 이는 다방향파의 쇄파 특성이 일방향파의 쇄파 특성과 상이함을 나타낸다.

• 한국해양공학회지
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• 제19권2호
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• pp.29-33
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• 2005

The accuracy of predicting wave transformation in the nearshore is very important to wave hydrodynamics, sediment transport, and design of coastal structures. Numerical experiments are conducted to identify the shoaling and breaking characteristics of a fully nonlinear Boussinesq equation-based model. Simulated shoaling showed good agreement with the Shouto's formula, and the results of the breaking experiment agreed well with experimented data, over several beach profile.

• 한국기계가공학회지
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• 제4권2호
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• pp.3-9
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• 2005

In this study, the chip breaking characteristics of S, PbS and BiS free machining steels have been assessed. PbS free machining steel shows the lowest value of chip thickness ($t_c$) under the same cutting conditions. SM10C steel has the largest value of the chip cross-section area ratio ($R_{CA}$). As the feed rate becomes larger the chip breaking cycle time ($T_B$) decreases and the chip breaking index ($C_B$) increases. The properly controlled-C type chip has been obtained with the value of $C_B$ between 0.05 and 0.2. Free machining steel, PbS produces the properly controlled-C type chip in a wider feed rate range than other steels.

• 한국정밀공학회지
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• 제11권6호
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• pp.179-184
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• 1994

In this study a nondimensional parameter, feed/land length(F/L) was introduced, and using this parameter, cutting performance and chip breaking characteristics of the groove and the land angle type chip formers were assessed. Specific cutting energy consumed and shape of broken chip with its breaking cycle time were appraised to find out the ranges of F/L value where efficient cutting and effective chip breaking could be achieved. C type chip was found out to be the most preferable in terms of cutting efficiency.

• 한국산업융합학회 논문집
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• 제2권2호
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• pp.181-186
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• 1999

For an unmanned machining system, the control and disposal of chips is one of the most serious problems at present. In order to perform chip control, feed/land length($F_L$) was introduced, and using this parameter, the cutting performance and chip breaking characteristics of groove-type and the land -angle-type chip formers were assessed. The specific cutting energy consumed and the shape of broken chips with its breaking cycle time were evaluated to find out the ranges of $F_L$ value where efficient cutting and effective chip breaking could be achieved. The C type chip was found to be the most preferable from the view point of cutting efficiency.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 춘계학술대회 논문집
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• pp.264-269
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• 2002

The wave profiles of directional breaking waves are investigated experimentally in a directional wave basin. The directional breaking waves are generated by component wave focusing both in direction and frequency based on constant wave steepness and constant wave amplitude spectrum models. the profile parameters of wave crest steepness and asymmetry are adapted to analyze the evolution of breaking ware characteristics in a view of focusing efficiency. The generated breaking waves are classified into the incipient, single and multi breaking waves.