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
제22권 제6호 (2020년 12월) 30건
1.
2020.12
구독 인증기관 무료, 개인회원 유료
초록 close In this study, the structural analyses were carried out with the old and new wheel models installed at the automotive tires. The stress and deformation at the middle circumference of wheel were seen to be greatest at two models. Also, the stress and deformation were smallest at the edge of wheel. The maximum deformation of the old model B is about five times larger than that of the new model A. The maximum equivalent stress of the old model B can be seen to be twice as large as the new model A. Also, it can be seen that the new model A is more stable than the old model B in terms of strength. It can be seen that the deformation energy of the old model B is 19 times larger than that of the new model A. And it is thought that the new model A is much more durable than the old model B in terms of impact. By utilizing this study result, the stress and deformation are investigated without the strength test of wheel installed at the automotive tire, and the durability can be seen.
4,000원
2.
2020.12
구독 인증기관 무료, 개인회원 유료
In order to satisfy the strengthening automobile exhaust gas regulation and CO2 regulation, the development of eco-friendly vehicles is actively progressing. To cope with these regulations, research on alternative fuel vehicles is being actively conducted. Alternative fuels are one of the best ways to reduce dependence on fossil fuels and respond to emissions and CO2 regulations. Natural gas, one of many alternative fuels, contains methane (CH4) as a main component and has abundant reserves, so it is attracting attention as a fuel that can provide stable long-term supply by replacing fossil fuels. In addition, natural gas has a high octane number, so there is room for improvement in combustion characteristics when used in SI engines, and it has the advantage of reducing harmful emissions and carbon dioxide (CO2) compared to conventional fossil fuels. When using a low-pressure injector in a turbo engine, it is difficult to secure the flow rate of fuel because the pressure difference between the injector and the manifold is small. Therefore, it is necessary to develop a high-pressure injector to improve this. Natural gas is a gaseous fuel and should be developed in consideration of compressible flow, Although the use of a CNG high-pressure injector is required, it is difficult to stabilize the flow due to the Mach disk and shock wave interference caused by compressible flow. If the flow is not stabilized, it is difficult to precisely control the flow. Therefore, it is necessary to develop an injector in consideration of flow characteristics. In this paper, the flow analysis according to the shape change of the injector was conducted to improve the fuel flow rate injected from the 800 kPa high pressure CNG injector.
4,000원
3.
2020.12
구독 인증기관 무료, 개인회원 유료
The bead geometry according to the welding conditions was analyzed through the laser fillet welding experiment of 9% Ni steel, and the relationship between the shear strength and the five bead geometry measured by selecting the main bead geometry of the fillet weld was analyzed. Among the welding conditions, the welding conditions that directly affect the penetration depth are welding speed and laser power, and the working angle and beam position have a great influence on the formation of leg of vertical and horizontal members. The bead shape, which greatly affects the shear strength, is the horizontal member length, neck thickness, and weld length, and has a proportional relationship with the shear strength. As a result of confirming the relationship between shear strength and bead shape through the derivation of the trend line, it was confirmed that the length of the vertical member, whose R2 value was 0.92, was most closely related to the shear strength.
4,000원
4.
2020.12
구독 인증기관 무료, 개인회원 유료
In this study, we studied the method of using general architectural glass instead of using the existing acrylic material for high luminance flat lighting. The flat panel lighting used the side illumination method to increase the ease of installation and aesthetic satisfaction. In general, glass has an amorphous structure with a lower angle of refraction than acrylic, so it is not suitable for use in flat panel lighting as a light guide, but in this study, the role of light distribution characteristics and diffusion patterns in the case of using such a glass light guide. Quantitative simulations were conducted to confirm new possibilities. In the simulation, the backlight estimation method was used, and about 10,000,000 rays were placed within a unit area in order to obtain a result similar to the real thing. As a result of the simulation, the geometry of the diffusion pattern could be specified, and the value of the geometry could be quantified using the ratio of the diameter and height of the pattern. As a result of the calculation, it was found that the maximum amount of light was generated around 75 degrees by quantitatively calculating the ratio and the outgoing light angle at which the maximum value of the outgoing light occurred between 05 and 1.0. As a result of these studies, it was confirmed that it is possible to use ordinary glass at the same time as a transparent window and light-emitting lighting at night.
4,000원
5.
2020.12
구독 인증기관 무료, 개인회원 유료
Using lanthanum zinc oxide (LZO) film with the ion-beam irradiation, uniform and homogeneous liquid crystal (LC) alignment was achieved. To fabricate the LZO thin film on glass substrate, solution process was conducted as a deposition method. Cross-polarized optical microscopy (POM) and the crystal rotation method reveal the state of LC alignment on the ion-beam irradiated LZO film. Between orthogonally placed polarizers, POM image showed constant black color with regular transmittance. Furthermore, collected incidence angle versus transmittance curve from the crystal rotation method revealed that the LC molecules on the ion-beam irradiated LZO film were aligned homogeneously. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were conducted to reveal the relationship between the ion-beam irradiation and the LC alignment. The ion-beam irradiation changed the LZO film surface to rougher than before by etching effect. Numerical roughness values from AFM analysis supported this phenomenon specifically. XPS analysis showed the chemical composition change due to the ion-beam irradiation by investigation of O 1s, La 3d and Zn 2p spectra. The ion-beam irradiation induced the breakage of chemical bonds in the LZO film surface and this occurred surface chemical anisotropic characteristics for uniform LC alignment.
4,000원
6.
2020.12
구독 인증기관 무료, 개인회원 유료
The brake system drives the vehicle by converting the kinetic energy into thermal energy. The heat energy generated during the braking process increases the temperature of the structure. It causes thermal deformation due to overheating and causes cracks, noise, and vibration that degrade performance. However, it is not possible to fundamentally prevent the temperature rise of the brakes. There is a need for research on improving the heat dissipation performance by improving the shape of the brake. Therefore, this study analyzed the concentrated stress caused by overheating of the brake disc. In order to improve the performance of the disk, shape optimization design was performed. For stress and thermal analysis, the analysis was conducted using the finite element program ANSYS Transient Thermal and Structural tools. PIAnO (Process Integration and Design Optimization) was used to perform optimal design. In the formulation of the optimum design, the stress was minimized by satisfying the constraints. This study intends to present a new brake disc model by performing perforated shape and arrangement.
4,000원
7.
2020.12
구독 인증기관 무료, 개인회원 유료
This study analyzes the internal temperature characteristics of heater module using a numerical method when the constant heat flux and heat flux time are applied to the surface heating element. The horizontal and vertical dimensions of heater module are 100mm, and the height is 5mm. The heat flux is 10,000W/m2, 15,000W/m2, and 20,000W/m2, and heat flux time is 5 seconds, 10 seconds, 15 seconds, 20 seconds, 30 seconds and 50 seconds, respectively. When the heat flux time was 50 seconds, the temperature of the surface heating element rose to 120.5°C, while the skin epidermis temperature rose 1.7°C. As a result, the surface temperature of the surface heating element increased greatly in the horizontal direction, while it increased low in the depth direction. This is because the heat conduction of the surface heating element is transmitted in the X-Y plane direction, and the thermal conductivity of the pet(polyethylene terephthalate) film and insulation sheet under the surface heating element is very low. when the heat flux at the surface heating element is 20,000W/m2, the skin's epidermal temperature rises up to 0.82℃ compared to 10,000W/m2 and 15,000W/m2.
4,000원
8.
2020.12
구독 인증기관 무료, 개인회원 유료
In this research, carbon nanotubes(CNT) and graphene nanoplates(GnP) are deposited on the surface of carbon fibers(CF) at once. Investigating the effect between CNT and GnP on increasing the interfacial and mechanical properties of carbon fiber reinforced epoxy composites(CFRP). The cross section of the CFRP composites indicates that the GnPs/CNTs hybrid coating exhibits significantly higher mechanical performance in all coating samples. The interlayer shear strength of the GnPs/CNT hybrid coated CFRP composite was 90% higher than that of the uncoated CF composite. The flexural and tensile strength of CFRP composites using GnPs /CNT hybrid coatings were improved by 52% and 70%, respectively, compared to uncoated CF.
4,000원
9.
2020.12
구독 인증기관 무료, 개인회원 유료
In this paper, the injectors with normal quantity, over quantity of +10%, under quantities of -10% and –30%, were mounted on S-ENG and P-ENG in order to measure the voltage energy, current energy and power supplied to the injectors and the fuel economy under several speed of rpm conditions. The voltage and current energy of S-ENG was greater than P-ENG, and the power of S-ENG was measured and analyzed 4.8 times higher than that of P-ENG at all injectors, and the tendency of carbon dioxide emissions calculated from fuel efficiency measurement results was not significantly affected by the type of injectors, but P-ENG was measured to be slightly affected by the type of injectors. It is assumed that the model year and mileage of the test vehicle affects this tendency.
4,000원
10.
2020.12
구독 인증기관 무료, 개인회원 유료
In this study, in order of to reflect the mold deformation in the injection molding process to design of mold, the mold deformation was analyzed by performing flow and structural analysis. The 5 inch LGP(light guide plate) mold, platen and tie bar were modeled and applied to the analysis. The result of melt pressure from flow analysis was extracted for use as boundary conditions acting on the mold surface in the structural analysis. In order to evaluate the accuracy of simulation analysis results, injection molding was performed under the process conditions of simulation. As a results, the mold deformation during injection molding tends to be similar that of injection pressure, and it is confirmed that it shows the behavior and properties of melt resins. Compared with the simulation and experiment, the error of the maximum mold deformation in the injection phase was 4.20%.
4,600원
11.
2020.12
구독 인증기관 무료, 개인회원 유료
In turbopump type liquid rocket engines, ignition and starting are known to be the most unstable and risky section among all operating sections of the projectile. The operation of the liquid rocket engine is the process of ignition and combustion of the main combustor after the turbo pump is driven into a stable section due to the turbine driving of the turbo pump and the ignition and combustion of the gas generator by the pyro starter. In this process, the driving of related components directly influences each other, so each component must be operated with sufficient reliability. In particular, if the igniter does not supply sufficient ignition energy at a predetermined time, an explosion may occur due to stagnation of the fuel/oxidant mixture, so reliability is more important. In this study, the fracture analysis of the gas generator igniter rupture disk according to the shape was performed using computational analysis. As a result, comparative analysis was performed to obtain the optimal dimensions according to each variable condition.
4,000원
12.
2020.12
구독 인증기관 무료, 개인회원 유료
LNG makes cryogenic conditions, so metals without low-temperature brittleness must be used. The International Maritime Organization (IMO) defines 9% Nickel steel, STS304L, 36% Nickel steel and Al5083 as metals that can be used in cryogenic conditions through the IGC Code. In this study, Al5083-O was studied to minimize welding distortion, and verified through finite element analysis and experiments. The block dumping method, which is advantageous in terms of analysis time and cost, was used, not the continuous heat source method. The constraint models with the thickness direction and the tensile force model were compared with the reference model, it was confirmed that the tensile force model had no significant effect. After verifying through the experiment, it was confirmed that the trend of the finite element analysis model was consistent with the experiment. Through this study, a welding distortion minimization model could be found with the block dumping method. It is judged that simulation of many models through short time analysis will be of great help in the field.
4,000원
13.
2020.12
구독 인증기관 무료, 개인회원 유료
The effect of flow direction on heat transfer in water cooling channel of lithium-ion battery is numerically investigated. Battery Design StudioⓇ software is used for modeling electro-chemical heat generation in the battery and the conjugated heat transfer is analyzed with the commercial package STAR-CCM+. The result shows that the maximum temperature and temperature difference of battery with Type 1 are the lowest because the heat transfer in the entrance region near the electrode is enhanced. As the inlet velocity is increased, the maximum temperature and temperature difference of battery decreases but the pressure loss increases. The pressure loss in Type 2 channel is the lowest due to the shortest channel length, while the pressure loss with Type 3 or 4 channel is the highest because of the longest channel length. Considering heat transfer performance and pressure loss, Type 1 is the best cooling channel.
4,000원
14.
2020.12
구독 인증기관 무료, 개인회원 유료
In this study, we compared of control characteristics at two-stroke marine diesel engine by MAN B&W. It was found that MC and ME type of engine largely divide fuel injection & exhaust valve actuator by cam-shaft controlled and electro-hydraulic controlled. Computer based type of engine ME-B type is only operated exhaust valve by driving camshaft, the fuel injection system is fuel oil booster and ELFI valve by Electro-hydraulic. ME-C type is composed of a multi-way valve or FIVA valve. Therefore fuel injection system and exhaust valve system is operated by Electro-hydraulic. ME type engine was shown that the optimization of the combustion process can be achieved for any load on the engine by Electro-hydraulic control system according to the computer based.
4,000원
15.
2020.12
구독 인증기관 무료, 개인회원 유료
In this study, the fatigue properties of press die steel, such as SKD11, and three high-durability die steel for the cold forming of ultra-high-strength steel sheets are evaluated. Specimens for fatigue, tensile, and hardness tests are manufactured through the heat treatment recommended by steelmakers and ultra-high precision processing. The general mechanical properties and fatigue properties are derived from hardness, tensile, and fatigue tests for four die steel. The tensile and fatigue properties of die steel derived through the tests are compared and analyzed. In particular, the correlation between the fatigue limit and the general mechanical properties such as tensile strength and elongation is analyzed, which allows relational expressions to be obtained through regression analysis. Finally, the study confirms that applying high-durability die steel is necessary for improving the die life in the manufacturing of press dies for ultra-high-strength steel sheets.
4,000원
16.
2020.12
구독 인증기관 무료, 개인회원 유료
In this study, the flow analyses were carried out on three kinds of front wing models. The down forces of front wings which influence the stability, cornering at driving were investigated with three models. At model 1, the maximum pressure shown on the main plate of front wing is 3177.539Pa. The maximum pressures at models 2 and 3 are shown to be 3429.677Pa and 3506.494Pa, respectively. The higher the pressure, the more resistance. So, the lower the pressure, the less resistance the model gets. At model 1, the maximum velocity of stream that flows under the front wing was shown to be the smallest among three models. In case of all three models, the pressure at which the air passes through the front wing is high in the upper part of the front wing. Among three models, model 1 is thought to be the most appropriate model to give the effect of the down force while reducing the flow resistance at driving. By utilizing this study result, the flow velocity and pressure are investigated without the flow experiment at driving due to the configuration of automotive front wing, and the flow resistance can be seen.
4,000원
17.
2020.12
구독 인증기관 무료, 개인회원 유료
Refrigerators used in homes occupy a large portion of the power consumption. In addition, most of the power consumption of the refrigerator is used by the compressor. Therefore, it is necessary to study on the improvement of compressor efficiency to save energy. In this study, the suction system was changed to improve the efficiency of the linear compressor. For this, numerical analysis was performed by linking the 1 dimensional lumped model and the 2 dimensional axisymmetric CFD model. The numerical analysis results were also compared with the experimental results. As a result of the numerical analysis, the model with modified suction system increased EER by about 0.25% compared to the basic model, which was also confirmed by experiment.
4,000원
18.
2020.12
구독 인증기관 무료, 개인회원 유료
As the International Maritime Organization (IMO)'s environmental regulations on ship emissions become strict, the demand for ships powered by Liquefied Natural Gas (LNG) is rapidly increasing worldwide. Compared to other materials, high manganese steel has the advantages of superior impact toughness at cryogenic temperatures, a small coefficient of thermal expansion, and low cost of base materials and welding rods. However, there is a limitation in that the mechanical properties of the filler material are lower than the base material having excellent mechanical properties. In this study, after performing a high manganese steel laser butt welding experiment, the welding performance was evaluated through mechanical property (yield strength, tensile strength, hardness, cryogenic impact strength) tests of the weld. As a result, it was observed that the yield strength and tensile strength of the high manganese steel laser welding part was 97.5% and 93.5% of the base metal respectively. Also the hardness of welding part was 84.2% of the base metal. The cryogenic impact strength of the welding part and the base metal were over the 27J, the level of welding part is 76.1% of the base metal.
4,000원
19.
2020.12
구독 인증기관 무료, 개인회원 유료
The paper studied the climbing structure and magnet selection method of exploration platform utilized for large-scale steel structures such as vessel surface. With respect to wall climbing robots, the study proposed a stable operation structure even in rapid incline change of vessel surface. Since the wheel-based operating method is hard to work flexibly in inclination changes, we employed joints and designed the robot to have a rotation joint in the center. The arrangement of wheels is an important aspect of this structure. Viewed from the side, the robot wheels should overlap with each other to have intersection points. The wheels here are ring-type permanent magnets and serve as a tool of attachment on walls. Based on the conditions identified through formula modeling, we proposed the required magnetic force. Important factors needed for magnetic force setup include platform weight, angle between ground and inclined plane, and friction coefficient. We considered only the required magnetic force for the stable adhesion of circular magnet while making not a separate mention about the necessary force for directional locomotion. The analysis results of ANSYS Maxwell are applied to magnetic attachment. Based on the final analysis results, we built a platform and found it did not slip and stayed attached on steel plate.
4,000원
20.
2020.12
구독 인증기관 무료, 개인회원 유료
Numerical analysis has been carried out to investigate the flow field characteristics for exhaust gas in automobile engine DPF system. The DPF system performance is largely affected by exhaust gas flow while it passes through the complicated geometry of DOC/DPF system, fan shape structure, and perforated can with air for fuel combustion. Hence the characteristics of fluid velocity, pressure, and streamline are analyzed with velocity uniformity in front of DOC and swirl flow near the fan. It can be seen that the velocity uniformity increases with the gas flow rate including flow acceleration near the lower area of the fan. The air flow also influences the gas flow distribution close to the impeller and fan structure with complicated swirl flow. These results are expected to be applicable as fundamental design data for automobile engine exhaust system.
4,000원
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