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
제21권 제4호 (2019년 8월) 31건
<학술연구>
1.
2019.08
구독 인증기관 무료, 개인회원 유료
The spray characteristics of two working fluids operating with a bi-fuel injector were investigated. A bi-fuel injector simultaneously sprays two working fluids, both of which possess different properties. An effervescent atomizer containing two separated aerator tubes was employed as the bi-fuel injector. Vegetable oil and kerosene were the working fluids. The mixing ratio and ALR were the experimental parameters. The mixing ratio is the mass fraction of vegetable oil in the total amount of working fluids. The ALR represents the ratio of the atomizing gas to the working fluid mass flow ratio. In order to examine spray characteristics, the spray angle, droplet size distribution, cumulative volume fraction, Sauter Mean Diameter and span factor were measured using a high resolution video camera and a Laser Diffraction Particle Analyzer. From the experimental results, spray angle is decreased with as the ratio of kerosene to vegetable oil in working fluid is increased. Regardless of ALR, SMD was the smallest when the only working fluid was kerosene and uniformity was the most stable when the only working fluid was vegetable oil.
4,000원
2.
2019.08
구독 인증기관 무료, 개인회원 유료
In this study, we investigated the properties of adhesive materials with different lightweight materials such as CFRP and Al-foam. The specimens were tested and analyzed using DCB (Double Cantilever Beam) specimens. In order to secure the reliability of the finite element method, the test and analysis were carried out, and the reliability of the finite element method was secured by using the graph of reaction force to displacement based on the experiment and analysis. The study on the adhesive failure characteristics according to the position of notch hole proceeded. Notch holes were generated at the locations of 40, 110, 150 and 190 mm from the beginning of the specimen near the bonding interface, and the analysis conditions used were the same as those used for securing reliability. The obtained study results are compared with reaction force and equivalent stress. In the case of reaction force, the overall tendency is similar but the difference in maximum reaction force is found. It was found that higher reaction forces appeared at the beginning than at the end of the bonding interface. When the equivalent stresses in the specimens were examined, the value of CFRP was seen to be 30 times higher as much as that of Al-foam.
4,000원
3.
2019.08
구독 인증기관 무료, 개인회원 유료
Magnetic abrasive finishing (MAF) process is a surface improvement method, which the magnetic field of permanent magnet or electromagnet is used to control the abrasive particles during the finishing process. The magnetic abrasive tools are filled between the N-pole and S-pole of Nd-Fe-B type permanent magnets. Tungsten carbide bar (WC) is a high hardness material and its compressive strength is much higher than the other materials. Therefore, due to its superior mechanical properties, it has been widely used in cutting or machining process. Because the smooth surface of tungsten carbide is required in cutting tools, thus the magnetic abrasive finishing process was applied for achieving its surface accuracy and dimensional accuracy. The results showed that the surface roughness of tungsten carbide bar was improved from Ra: 0.23㎛ to Ra: 0.02㎛ in 120 sec by magnetic abrasive finishing process.
4,000원
4.
2019.08
구독 인증기관 무료, 개인회원 유료
An aluminium sandwich sheet is the composite adhered by rolling two aluminum panels to one plastic core. If it has the same bending stiffness as an steel sheets, it is about 65% lighter than steel sheet and 30% lighter than aluminum sheet. In present study, we intend to develop application technologies of an aluminum sandwich sheet for auto body panels from selecting composed materials of aluminium sandwich sheets to fabricating prototype. For this study, for the application of a light sandwich sheet to an automotive hood part, ribbing process so called, hemming for which joined between an inner and an outer panel was introduced. From these results, it was found that the sandwich sheet could improve the weight and maintain the flexural rigidity simultaneously comparing to the steel sheet.
4,000원
5.
2019.08
구독 인증기관 무료, 개인회원 유료
In order to enhance the utilization of underground heat including underground water, the comparison between the existing high density polyethylene underground heat exchanger and the newly developed metal heat exchanger was conducted to suggest the potential use of geothermal energy corresponding to the geological characteristics of Jeju Island. When the acquired heat of the underground loop system test condition of the KS B 8292 water-water geothermal heat pump unit was compared by installing heat exchanger of HDPE material and the heat exchanger of STS material under the same bore hole condition, the total heat area of the heat exchanger of STS material was about 15% less than HDPE, but the acquired heat was estimated to be about 4 times or more.
4,000원
6.
2019.08
구독 인증기관 무료, 개인회원 유료
In case of a low speed gearing in the automatic transmission, since the torque is increased, it is difficult to secure a good feeling on gear shift of transmission. It is possible to improve the shift feeling on transmission by applying a one-way clutch in case of the gear shift from the first stage to the second stage. But in case of the gear shift from the second stage to the third stage, it is difficult to secure a good feeling on gear shift of transmission because the hydraulic components are directly controlled simultaneously. In this study, a shift performance of an automatic transmission was investigated as a basic study to solve these problems. The subjects of this study are 2-3 step upshifting gearing process and the performance data such as the pressure characteristics and torque of the transmission according to the amount of the throttle valve opening are analyzed on basis of experiment with an actual vehicle. As a result, the transient time of the shift is closely related to the amount of the throttle valve, opening and the time point at which the shifting ends is shortened when the throttle valve opening reaches 30% of the opening amount.
4,000원
7.
2019.08
구독 인증기관 무료, 개인회원 유료
At a two phase flow, according to gas and liquid phase flow rates, various flow regimes are developed such as bubbly, slug/plug, churn, annular, droplet flow and so on. At a two phase flow in small scaled channels, among various flow regimes, the intermittent flows such as bubbly, slug/plug flow are developed in the broad regions of two phase flow pattern map. In particular, the flow regimes are influenced by surface wettability. In a case of slug flow in hydrophobic small scaled channels, gas and liquid phases are perfectively separated by interfaces and contact line. The pressure drop of the two-phase flow is largely generated at moving contact line. Therefore, to well design two-phase flow system with small scales, it is important to estimate the pressure drop at moving contact line. In this study, on the basis of previous research, the pressure drop at moving contact line is experimentally measured for a various fluids (0-40% water-ethanol mixtures). And, the previous correlation to estimate pressure drop at moving contact line is verified by experimental data. In an addition, we discuss interfacial broken phenomena of slug flow in a minichannel. (D=1.555mm).
4,000원
8.
2019.08
구독 인증기관 무료, 개인회원 유료
In this research, a simulation program is developed in order to investigate non steady-state cornering performance of 6WD/6WS special-purpose vehicles. 6WD vehicles are believed to have good performance on off-the-road maneuvering and to have fail-safe capabilities. But the cornering performances of 6WS vehicles are not well understood in the related literature. In this study, 6WD/6WS vehicles are modeled as a 18 DOF system which includes non-linear vehicle dynamics, tire models, and kinematic effects. Then the vehicle model is constructed into a simulation program using the MATLAB/SIMULINK so that input/output and vehicle parameters can be changed easily with the modulated approach. Cornering performance of the 6WS vehicle is analyzed for brake steering and pivoting, respectively. Simulation results show that cornering performance depends on the middle-wheel steering as well as front/rear wheel steering. In addition, a new 6WS control law is proposed in order to minimize the sideslip angle. Lane change simulation results demonstrate the advantage of 6WS vehicles with the proposed control law.
4,000원
9.
2019.08
구독 인증기관 무료, 개인회원 유료
Angiography has excellent advantages to visually observe the internal morphology of the stenosed blood vessel. For OCT(Optical coherence tomography), it is possible to directly provide a reliable two-dimensional cross-sectional information as compared to conventional angiography. In the present study, both velocity and wall shear stress distributions were numerically investigated using stenosed blood vessel models (0%, 25%, 50%, and 75% stenotic expansion rate). The blood vessel geometry was prepared based on the human stenotic aorta from OCT image. Commercially available software (CATIA V5) was used to reconstruct 3D blood vessel for numerial analysis. Pulsatile blood flow boundary condition was applied. The numerical study could help our understanding of the hemodynamic differences in a stenosed blood vessel.
4,000원
10.
2019.08
구독 인증기관 무료, 개인회원 유료
The curvature of spacetime represented by Einstein field equation has many physical implications, including gravity. As light is deflected by the curvature of spacetime, a magnetic field will also be influenced by the curved spacetime. A permanent magnet is generally known to maintain its persistent magnetic field on the ground as long as there is no external magnetic interference. However, a series of experiments find that there are noticeable changes in the magnetic fields distribution while the permanent magnet rotates. The magnetic field lines of the permanent magnet are deflected towards Earth’s centre, implying a possibility that we can use magnetic field, a more efficient tool than a satellite, to measure the curvature of spacetime. However, comparing the experimental results of this study with theoretically obtained values of the curvature of spacetime remains a vast area of research for future studies.
4,000원
11.
2019.08
구독 인증기관 무료, 개인회원 유료
A deburring system using the joint of revolute robot manipulator with a tool holder was developed for deburring automation. The tool holder composed of the plunger with spring was developed for freedom of three degree operation. The tool holder was applied for compensation of position errors during trajectory tracing or deburring the workpiece of ununiform. To reduce interacting forces between the high stiffness tool at the end effecter and the workpiece during deburring operation, it was developed to operate flexibly to the direction of tangent line on the revolute axis and to the direction of axis.
In this paper, using the deburring system attached at the revolute robot manipulator, deburring experiments were performed. According to the experimental results, the good performance of the proposed deburring system using the revolute robot manipulator was shown.
4,000원
12.
2019.08
구독 인증기관 무료, 개인회원 유료
This paper is concerned to develop a fluid pressure system for the control of artificial bladder urine discharge. The primary goal is to force the fluid into the space between the inner wall and the outer wall by using a pump in the artificial bladder having a double structure of inner and outer walls and to form the urine discharge pressure by the contraction of the bladder inner wall due to the movement of the fluid. The ANSYS_CFD analysis is used to confirm the delivery of fluid pressure in the artificial bladder model, and the ANSYS_FSI analysis is used to identify the deformation and internal pressure of the artificial bladder through the delivery of fluid pressure, and to identify the discharge of urine. As the design parameters of the modeling of the artificial bladder and the fluid flow field, the capacity of the flow field, and the pump pressure input value were selected.
4,000원
13.
2019.08
구독 인증기관 무료, 개인회원 유료
In this study, the temperature, the absolute humidity, and the turbulent flow characteristics of exhaust air and supply air in the mixer were studied while changing the shape of the mixer of the white smoke reducing heat exchange system. Using Solidworks, the mixer of the white smoke reduction heat exchange system was created by 3-D model. Also, the mixed flow of supply air and exhaust air inside the mixer under the uniform inlet conditions was computed, using the solidworks flow simulation. Two types of improvement models were selected by using a perforated plate and a guide vane as a turbulent mixing flow control method of the mixer. The mean temperature and mean absolute humidity of the mixture were greatly decreased according to the internal shapes of Case 1, 2, and 3. The temperature difference between the inlet and outlet of the mixer Case 3 was 26℃. The exit temperature and absolute humidity reduction rates of Case 3 were 26.2% and 48.1%, respectively, compared with Case 1.
4,000원
14.
2019.08
구독 인증기관 무료, 개인회원 유료
Excellent plastic moldings is possible through optimization of many molding parameters. In particular, the deformation of a plastic part is affected by various factors during molding. Therefore, it is very important to select the optimum molding conditions that minimize the deformation of the molded part. Experimental design is used to select optimal molding conditions. In this study, the molding conditions were selected to minimize the deformation of the electric plastic plug of the electric vehicle using the Taguchi method in the experimental design method. Using the Taguchi Method, we found that the deformation of the plug moldings was reduced by about 7.2% compared to before optimization.
4,000원
15.
2019.08
구독 인증기관 무료, 개인회원 유료
CNC cutting process has been mainly used for processing metal materials, and wood processing is also changing to machining by CNC machine. But the researches on the CNC machining of wood and its characteristics were rarely carried out.
In this study, we analyzed the machined surface according to the cutting conditions such as the cutting direction, spindle speed, feed rate, cutting depth, chip removal in the CNC machining of wood. The consideration of cutting conditions and their effects on the surface finish will provide possibilities for improving the wood machining processes.
4,000원
16.
2019.08
구독 인증기관 무료, 개인회원 유료
One simple way of increasing the heat transfer for a fin-and-tube heat exchanger is to increase the fin surface area. In this study, a series of tests were conducted on wide slit fin heat exchangers having an increased fin area (Pl/Pt = 0.87), and the results were compared with those of standard slit fin heat exchangers (Pl/Pt = 0.6). Thermal performances of wide silt-finned samples were superior to those of standard slit fin samples. For one row configuration, the j factor of the wide slit fin sample was 11% larger, and the f factor was 33 % smaller than those of the standard slit fin sample. The difference decreased as the number of tube row increased, although wide slit fin sample always yielded superior performance, The reason was attributed to the many narrower slits formed on the wide fin sample. Furthermore, the effect of fin pitch on j and f factor was not significant, and j factor decreased with the increase of the number of tube row.
4,000원
17.
2019.08
구독 인증기관 무료, 개인회원 유료
Damping and sound absorption not only reduce environmental pollution caused by vibration and noise, but also improves processing accuracy, resolution of precision measuring instruments and fatigue life of machine parts in various precision machines. The vibration-damping plate is largely divided into a constrained type in which the resin is confined by a plate and a non-constrained type in which a plate is made of a polymer material mainly composed of polymer. The external vibration energy is absorbed by the thermal energy required for friction, stretching and compression of resin, so that the noise and vibration generated by resonance are reduced. The vibration damping ability of the sandwich plate produced in this study was found to be somewhat superior, which may be due to the difference in adhesive force during the manufacture of the sandwich plate. In the experimental results, it was confirmed that the sandwich plate material is superior to the vibration damping ability than the 5182 aluminum single plate material, it can be seen that the sandwich plate is effective for vibration damping of the aluminum alloy plate material.
4,000원
18.
2019.08
구독 인증기관 무료, 개인회원 유료
LDV(laser Doppler velocimetry) measurements were conducted at a total of four planes at 0.4 speed ratio. The speed ratio of 0.4 is 1600rpm of impeller and 633rpm of turbine speed. Even at the speed ratio 0.4, fluid flow at the gap region between the impeller and turbine and impeller exit was leaving the impeller and flowing up behind the turbine, and flows were affected by the turbine blade as it passed, negatively effecting converter efficiency. In the gap region, fluctuations make a clear sinusoidal trend unclear. The rise and fall of the flow rates in a broad sense, indicate a dependency based on the passage of the turbine blade in front of the impeller passage exit but a sinusoidal trend is not evident from this data.
4,000원
19.
2019.08
구독 인증기관 무료, 개인회원 유료
This study examines the domestic and international bulletproof test standards of armor and plate which are supplied to the domestic market. In addition, improvements and suggestions for the test standard were presented. Experiments were conducted to clarify the distances to the edge, the difference between ammunition makers, and the position of the impact point of the bulletproof plate, which have been discussed in the conventional bulletproof test. As a result of the study, it was confirmed that the bulletproof performance is excellent as the distance from the edge increases. Next, performance differences between ammunition makers were not found. Finally, plates should be applied to the US ESAPI test specification to provide a clear and reproducible test method.
4,000원
20.
2019.08
구독 인증기관 무료, 개인회원 유료
In this study, the experiments and analyses were carried out in order to investigate the fracture characteristics on the adhesive at the specimen bonded with aluminum and aluminum-foam. The same conditions were given for the experiments and analyses. The results are investigated by the graph of reaction force according to displacement. It was found that the experimental and the analytical data were very similar to each other. On the basis of the data, the reliability of the analysis data could be confirmed. The notches were produced at the distances of 40, 110, 150, and 190 mm from the front of the test specimen, and the maximum reaction force was compared accordingly. It was found that the highest reaction force was generated at the front end of the adhesive and the lowest reaction force was found at the middle of the adhesive interface. Finally, when the equivalent stress in the test specimen was examined, it was found that the highest stress was obtained at the distance of 110 mm. It can be deduced. As the notch formation point are similar to the point when stress is dispersed as the adhesive is peeled off, it is possible to infer the high stress compared to other test specimens.
4,000원
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