간행물
한국기계기술학회지 KCI 등재 Journal of the Korean Society of Mechanical Technology 韓國機械技術學會誌
- 발행기관 한국기계기술학회
- 자료유형 학술지
- 간기 격월간
- ISSN 1229-604X (Print)2092-0385 (Online)
- 수록기간 1999 ~ 2024
- 주제분류 공학 > 기계공학 공학 분류의 다른 간행물
- 십진분류KDC 550DDC 620
권호리스트/논문검색
제20권 제5호 (2018년 10월) 30건
학술연구
1.
2018.10
구독 인증기관 무료, 개인회원 유료
An elliptic blending Reynolds stress transport equation model for Newtonian fluids has been extended to predict polymer-induced drag reduction FENE-P fluids. The conformation tensor equation which is related to the polymer stress is adopted from the model form of Resende et al., and the models of redistribution and dissipation rate terms for the Reynolds stress transport equation are considered by the elliptic blending equation. Also, the new model terms for viscoelastic turbulent transport and viscoelastic dissipation in the Reynolds stress transport equation are introduced to consider the polymer additives effect. The prediction results are directly compared to the DNS data to assess the performance of the present model predictions.
4,000원
2.
2018.10
구독 인증기관 무료, 개인회원 유료
In a sheet metal forming process, fracture and wrinkle are the most difficult task in new parts launching. The variation in process condition generates the fracture and wrinkle fluctuation. The fracture and wrinkle are very sensitive to the process conditions, then the main effects of the design variables cannot be obtained from the standard mean analysis. Therefore, in order to minimize the fracture and wrinkle in parts of automobile, a special method to counterpart is required. In this study, a new design method to achieve the optimal in the sheet metal forming process is proposed. The effectiveness of the proposed methods is shown with an example of the parts of fracture and wrinkle.
4,000원
3.
2018.10
구독 인증기관 무료, 개인회원 유료
In the case of the visually impaired, in order to pick up an object, the entire shape is grasped while straddling the object first. When we grasp the characteristics of the object sufficiently by using the tactile sense of the hand, we touch the point which is the center of gravity and listen to the object once. When you want to perform object-graping with only the tactile sense under the conditions of other senses, such as vision, a series of actions is repeated. This paper deals with the behavior based control study of the robot hand using the tactile sense and applied to the 4 DOF hand developed by our laboratory by evolving the subsumption architecture (SA) proposed by R.Brooks.
4,000원
4.
2018.10
구독 인증기관 무료, 개인회원 유료
In this study, the fatigue and vibration analysis were performed by using Solidworks program to investigate the damage percentage, life cycle and vibration mode depending on the types and positions of load applied to the table (Cases 1, 2, 3, 4). The farther the point of action of the load was, the more the fatigue damage and stability of the table were greatly reduced. The life cycles of Case 1 and 4 were over 100,000 cycles and the fatigue damage was less than 70%. From the vibration analysis, five modes and natural frequencies of Case 1 were confirmed. As the natural frequency increases, the shape of the corresponding mode is predicted not to be deformed.
4,000원
5.
2018.10
구독 인증기관 무료, 개인회원 유료
This Study is carried out to stabilize the system according to the change of superheat and subcooling in binary refrigeration system by applying cascade system. When the system on 1 st stage was started and the system on the other side was operated, a temperature reversal phenomenon occurred in which the temperature of the 1 st cascade outlet was temporarily lowered. This means that the condensate heat exchange on the 2 nd is not good, which can cause the compressor to overheated. In order to maintain stable system operation, the opening degree of the expansion valve is controlled to increase the refrigerant circulation amount, thereby facilitating the condensation heat exchange on the 2 nd stage system. We have found that the most suitable refrigerant circulation amount is found by stabilizing the operation of the system while lowerning the super low temperature from -65℃ to -70℃ and increasing again to -60℃.
4,000원
6.
2018.10
구독 인증기관 무료, 개인회원 유료
This study describes the effects of palm oil biodiesel (PD) blended with diesel on the combustion performance, emission characteristics and soot morphology in a 4-cylinder CRDI diesel engine. 5 kinds of fuels are used with blending as diesel/biodiesel volume ratio 0%, 10%, 20%, 30%, 100%. The engine is operated under idle speed, 750rpm and load conditions of the engine are 0 Nm and 40Nm. The Coefficient of Variation(COV) of Indicated Mean Effective Pressure(IMEP) shows that the engine operates very steadily in the idle state. But fuel consumption is increased. And Emission results show that the oxygen in biodiesel has a great influence on the production of exhaust emissions. The nitrogen oxides(NOx) is decreased because of high viscosity and low heating values of biodiesel at low blend ratio. But NOx and Carbon monoxide(CO) are increased above a certain blend ratio. Particulate matter(PM) and Hydrocarbons(HC) is decreased according to increase of blend ratio. The size of soot is decreased and the morphology of soot is developed to cluster with increasing blend ratio.
4,000원
7.
2018.10
구독 인증기관 무료, 개인회원 유료
The wavy fins have been widely used on the compact heat exchangers in aero system, automotive, air-conditioner and cooler system. The Special Purpose Vehicle has many oil used system and it need cooling system by air in form of fin-flat tube heat exchanger. The objective of this work is to evaluate the performance of wavy fin by Computational Fluid Dynamics(CFD) analysis. 3 modified models were suggested to change protrude direction or to remove blocked surface bot and top of corrugated fin. The base model shows the lowest performance in pressure drop, and modified model 3 shows the highest performance in heat transfer rate. But, modified model 2 has the highest value in the Area goodness factor results, and modified model 3 has the highest value in the Volume goodness factor results.
4,000원
8.
2018.10
구독 인증기관 무료, 개인회원 유료
In this study, Equivalent fracture strain and Fracture energy were evaluated with the small punch test(SP test) for friction stir welded(FSW) Al6061-T6 sheets. With the three rotation speeds and the three feeding rate, The nine different conditions of FSW were prepared for the SP test. The SP test specimens were manufactured and tested on the advancing side, center, and retreating side to the tool rotation direction. From the SP test data, the equivalent fracture strain and the fracture energy were analyzed. The high value of equivalent fracture strain was attained form tool rotational speed 900RPM and feeding rate 330mm/min. It is found that its characteristic is about 14% higher than the value of condition 1100RPM-330mm/min that have the lowest value. The high value of fracture energy was obtained from the tool rotation speed 900RPM and feeding rate 330mm/min. The lowest fracture energy, which from 1000RPM-300mm/min, was approximately 16% difference to the highest value.
4,000원
9.
2018.10
구독 인증기관 무료, 개인회원 유료
The effect of water vapor addition on the ignition delay of iso-octane/air mixture was numerically investigated with detailed chemical reaction mechanism. The Chemkin-III was utilized to evaluate the delay time of autoignition for isobaric conditions. By dilution effect and thermal effect, water vapor addition increases the ignition delay time. However, the chemical effect by adding water vapor makes the ignition delay shortened. The ignition delay by the chemical effect is reduced by two ways. Dissociation of water vapor increases the quantities of OH and H. One way is that OH directly makes the rate of iso-octane oxidation reaction 2 increase. The other is that HO2 is produced more by three-body reaction, H+O2+M →HO 2+M, which makes the rate of iso-octane oxidation reaction 3 increase. All trends of three effects are similar according to water vapor addition.
4,000원
10.
2018.10
구독 인증기관 무료, 개인회원 유료
In this paper, Fly robot with electric power, a kind of Unmanned aerial vehicle (UAV), is considered as an autonomous hovering platform, capable of vertical lift-off, landing and stationary hovering. This aircraft has four rotor and DC motors of electrical Power, which is capable of Omni-direction for indoor application. In the earlier days of vertical flight experimentation developers looked at the intuitively easy control functionality of 4 rotor designs. But we need to obtain design method of suitable structures and adequate components because the existing prototypes of 4 rotor-craft don't analyze the propeller, motor characteristic and propose a methodology to optimize this system. In design of propeller, experimental results show that thrust and power are relatively efficient at a pitch angel of 20 degree. To the conclusion, the design method and optimization method of the propeller, motor, frame, Blimp, which are the main design elements of the blimp type 4 rotor craft, were studied to optimize the existing Blimp 4 rotor craft body design method.
4,000원
11.
2018.10
구독 인증기관 무료, 개인회원 유료
Cooling operation characteristics of multi-A/C(air conditioner)s were experimentally investigated for combination of indoor units (A+B, A+C, B+C) and operating conditions (standard, overload, low temperature and low temperature freezing). The operating data and performance of the air conditioner were measured using a multi-calorimeter. We also observed compressor frequency and pressure variations. From the experimental results, it was found that the cooling performance and the operating characteristics depend on operation combination of indoor units, in the case of 2 room simultaneous operation. In the four types of cooling tests, the cooling capacity and COP of the 3 room simultaneous operation and 2 room simultaneous operation were similar. Through this experimental study, data on the simultaneous operation characteristics of 2 room simultaneous operation according to the changes of indoor and outdoor temperature of four kinds were obtained.
4,000원
12.
2018.10
구독 인증기관 무료, 개인회원 유료
In this paper, the long-term reliability of swash plate type hydraulic pump is studied by prognostics method. For the purpose, the pumping power of hydraulic pump is measured for 00 cycles and the performance after 00 cycles is estimated using the particle filter method. To verify the predicted 00 cycle's performance, the actual test results are compared with the estimated result and the trend of estimation is well matched with actual test results. The long-term reliability evaluation using the prognostics method performed in this study shows the feasibility that can be utilized in development phase of tracked vehicle to improve the quality of initial products.
4,000원
13.
2018.10
구독 인증기관 무료, 개인회원 유료
In this study, the whole process of 6xxx series aluminum extruded alloy for high speed train interior and exterior parts are characterized. The mechanical properties, and chemical composition of the case materials were evaluated for the 6063, 6061 and 6N01 alloy profiles and compared to the commercial materials and the evaluation results satisfied the standard. The cast product was extruded using the air slip(AS) casting method and the direct casting(DC) method and these were again heat-treated conditions with T5 or T6. The remarkable point is that the extrusion temperature and pressure of 6061 alloy were somewhat higher than those of other alloys. The reason is that 6061 alloy exhibited brittle fracture due to grain boundary segregation even at the tensile fracture surface and the fact that the product used a billet by the direct casting method instead of air slip one. The mechanical properties were evaluated for the 6063, 6061, 6N01 extruded alloys and the evaluation results were analyzed and satisfied the standard properties.
4,000원
14.
2018.10
구독 인증기관 무료, 개인회원 유료
Numerical analysis has been carried out to investigate seawater flow field characteristics with various current directions near the manganese nodule mining device. Seawater flow near the collecting device is largely influenced by the sea current direction, especially along the downstream of the rear system. Predicted flow velocity distributions are analyzed with turbulent kinetic energy and drag force. There is big flow field variation when the direction angle between the mining device and seawater current flow approaches to 30°~ 120°, and flow velocity along the rear region of 60° becomes faster than 180°. Averaged turbulent kinetic energy at 180° also becomes low, about 57% higher at 60°. These results from the study can be applicable to the optimum design of manganese nodule collecting system in the deep seawater flow.
4,000원
15.
2018.10
구독 인증기관 무료, 개인회원 유료
During indoor air conditioning, cold condensate is generated. But until recently, this condensate has not been recycled. This experiment and research is on the technology of the condensed water recycling in air conditioning. This study demonstrates the effect of condensate recycling, contributes to energy saving and water use reduction. For this purpose, the test equipment was installed to measure the temperature of the condensate generated in the fan-coil unit, and the performance of the high-pressure pump to be applied to the cooling pipe was examined. As a result, the water quality and energy saving effect.
4,000원
16.
2018.10
구독 인증기관 무료, 개인회원 유료
The objective of this study is to construct the inspection standards of motorcycle brake system performance. Based on the Korean Motor Vehicle Safety Standards (KMVSS), the Korean Motor Vehicle Inspection Standards (KMVI), the inspection standards of the International Motor Vehicle Inspection Committee (CITA), United Kingdom and Japan, three alternative brake performance criteria were suggested. The brake performance tests for 129 various models of used motorcycles were conducted for verifying the developed test equipment and suggested three alternative criteria. The total brake performance criterion is appropriately suggested to set at 50 %. Considering the KMVI or the CITA, the brake performance criterion of rear axle may suggested to set at 20 % or 25 %, either.
4,000원
17.
2018.10
구독 인증기관 무료, 개인회원 유료
In this study, we have investigated the optimal control method and the energy saving possibility when the dimming control for lighting and the suspended particles display(SPD) glass for window were applied to reduce the lighting load and the cooling load in office buildings. Simulations were carried out during from 8:00 am to 7:00 pm of typical one day on summer, winter and intermediate season. Simulation results showed that the cooling and lighting energy usage was reduced to 21.2% compared to the baseline model. Therefore, it was possible to predict the optimum control method of the suspended particles display(SPD) window to control the transmittance for energy saving and the dimming control for lighting during summer season.
4,000원
18.
2018.10
구독 인증기관 무료, 개인회원 유료
In this paper, we analyze various types of racing lines and search for the optimum time to pass through the chicane, which are corners smaller than 90 degree. “Best” means the minimum time at maximum speed. This indicates that the inside and outside of the running line is not able to never win the internal between the connected lines. Even in the case of Chicane driving, the vehicle can accelerate at a high speed by increasing the turning radius near the straight line. In the study, the turning angle is inevitable if the angle is large because the turning angle is 44.3 because there is no straight running width. Therefore, by keeping the speed close to the straight line along the path of the incinerator, the speed of escape from the line can be shortened.
4,000원
19.
2018.10
구독 인증기관 무료, 개인회원 유료
Vortex tubes are simple tubes that can separate hot and cold air from compressed air without any internal device configuration and are used in many industries. If the vortex tube with these advantages is applied to an air conditioning system, it will be free from the use of refrigerant. In this study, basic study on discharge flow rate and temperature separation characteristics was carried out by varying the number of generator nozzle hole in various shapes of the vortex tube according to the inlet pressure of the vortex tube. Experimental results show that as the number of nozzles increases, the discharge flow rate tends to decrease and the temperature separation characteristics were excellent in the number of nozzles 6~7.
4,000원
20.
2018.10
구독 인증기관 무료, 개인회원 유료
Recently the incidence of rollover accidents has increased due to the increase of SUV, and the probability of occupant injury in rollover accidents is very high, so research is needed accordingly. In this study, PC-CRASH, which is a program used for traffic accident analysis, is used for checking rollover speed and rollover angle of each situation in case of rollover accident, and applied to design variables of LS-DYNA which is finite element analysis program, so deformation displacements of roof according to collision velocity and angle were derived. Also, it is possible to predict rollover vehicle speed by using the derived value and the measured deformation displacement of roof in actual rollover accident, and it is possible to reconstruct accident more accurately by applying to PC-Crash which is traffic accident reconstruction program, so it is thought that it can be utilized analyzing traffic accident usefully.
4,000원
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