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
제25권 제5호 (2023년 10월) 46건
1.
2023.10
구독 인증기관 무료, 개인회원 유료
It is essential to select materials with excellent mechanical properties to prevent chemical and mechanical damage to the surfaces of materials used in machines and structures and to extend their lifespan. Co-based stellite alloy, which has wear resistance, heat resistance, and corrosion resistance, is essential for products used in harsh environments. However, due to the problem of enormous costs, research on hard facing, which uses a stellite coating layer only on the contact surface, is urgently required. Currently, high-facing research on Stellite coating layers is focused on powder, and GMAW research using wire is relatively lacking. In this study, welding experiments were performed to form stable weld beads using stellite 6 welding wire, and the correlation between parameters and weld beads was analyzed. A CMT welder was used to minimize the heat effect on the base material.
4,000원
2.
2023.10
구독 인증기관 무료, 개인회원 유료
ars using diesel have always had problems with reducing exhaust fumes, and have been studied steadily in this regard. There were studies on the remanufacturing effect of DOC catalyst deactivated by diesel vehicle smoke reduction device, analysis of vehicle fire accident cases caused by damage to diesel vehicle smoke reduction device, and related studies on the remanufacturing effect of diesel vehicle smoke reduction device DPF. This study also developed an optimized system for complete combustion of smoke generated by institutions using diesel engines in low-temperature exhaust gases. The main systems to be developed are high-performance heaters, burner structures that can maintain ignition in exhaust flows, and exhaust flow control units that reduce exhaust gas backflow effects caused by diesel engines.
4,000원
3.
2023.10
구독 인증기관 무료, 개인회원 유료
In general, a large mirror without weight reduction in large optical or space telescope systems can increase the system’s weight or lead to significant deformation of the mirror surface. Thus, it is imperative to pursue lightweight design strategies. In this paper, the structure design of a spherical mirror, a diameter of 600mm and a mirror radius of 2,000mm, was investigated to reduce weight and minimize deformation. To establish load paths for internal and external loads, stiffeners were added across the lateral supports. This approach effectively reduced both weight and deformation caused by gravity. Weight reduction and reduction percentages were quantified, and the mirror deformation was evaluated by using finite element analysis (FEA). The proposed structures were compared with honeycomb structures for weight reduction. This evaluation allowed to assess the deformation characteristics and the potential advantages of the proposed structures for lightweight mirrors.
4,000원
4.
2023.10
구독 인증기관 무료, 개인회원 유료
In this study, when Butyl ether, a type of diether-based oxygenated fuel, is mixed in each volume ratio in a naturally aspirated direct injection diesel engine, the exhaust gas emission characteristics of the oxygenated component in the fuel affect each operating area of the engine I wanted to investigate the effect on. For comparative measurement of engine performance and exhaust emissions, commercial diesel and butyl ether mixed fuels were classified into 4 types according to the mixing ratio and tested. As the content of butyl ether in fuel increases, soot emission reduction increases, and when the maximum mixing amount of butyl ether (diesel 80vol-% + BE 20vol%) is applied, compared to the case of using only diesel as fuel, at 2500 rpm and no load, 39%, and about 32% of smoke reduction effect at full load was confirmed.
4,000원
5.
2023.10
구독 인증기관 무료, 개인회원 유료
The effect of the stacking order of carbon fiber composites on impact damage was studied. The main form of damage was delamination starting at the interface between individual ply. The force-time response when the impact was applied was monitored and the energy absorbed by the panel was analyzed. The energy absorbed during interlayer separation was found to be affected by the stacking order, and the residual energy absorbed by peel propagation increased linearly as the total peel area increased. It was found that the compressive strength after impact was related to the maximum delamination area.
3,000원
6.
2023.10
구독 인증기관 무료, 개인회원 유료
Recently, the International Maritime Organization is strengthening regulations for ships operating in polar regions. Hence, insulated multi-core tubes as components for vessels operating in extreme cold need to be investigated in various aspects. Furthermore, the demand for research on electric propulsion vessels is also increasingly growing. Thus, to utilize a 4-core insulated multi-core tube with glass wool as insulation, which was previously developed for ships operating in polar regions, as a water-cooled electrical cable, this study conducted an experiment on the temperature change when water at normal temperature 25℃ was supplied as a coolant under the overcurrent varied from 10A to 25A. As a result, the temperature increase of the core in 10A condition was 3.3℃, but it increased to 13.05℃ in the 25A condition. This showed that a temperature difference of approximately 9.75℃ occurred according to the overcurrent load. However, the coolant inlet and outlet temperatures were relatively uniform around 1℃ in all conditions. This suggests that increasing the residence time by proper control of the coolant flow in the future could achieve a higher cooling effect.
4,000원
7.
2023.10
구독 인증기관 무료, 개인회원 유료
In this study, numerical analysis was performed for the purpose of analyzing the flow characteristics and performance according to the change in the inflow hydrogen temperature and differential pressure of the receptacle of the hydrogen charging system. The pressure distribution and turbulent kinetic energy in the filter area were analyzed by changing the outlet pressure condition under the inlet hydrogen temperature condition, and the flow velocity change at the outlet was compared and analyzed. As a result of the analysis, as the differential pressure decreased, the flow rate at the outlet of the receptacle decreased by up to about 70% at the 2.86 MPa condition compared to the 1.86 MPa condition, and the mass flow rate decreased by about 56.5% at the maximum. It was found that the standard CV performance was not satisfied when the differential pressure at the inlet and outlet was 1.12 MPa or less under the 363K temperature condition.
4,000원
8.
2023.10
구독 인증기관 무료, 개인회원 유료
A Study on the Revitalization of Marine Tourism in Gyeongsangnam-Do by Futuristic Air Transportation
This study divided the coast of Gyeongsangnam-do into three specialized base areas to revitalize tourism on the southern coast and suggested using AAM for movement within base areas. It analyzes the feasibility of advanced transportation means to revitalize coast tourism. It presents a new perspective and the environmental change in the tourism field. The results of this study are expected to have great implications in that it’s applicable to all marine tourism on the southern coast, including Jeollanam-do and Busan, beyond Gyeongsangnam-do.
4,000원
9.
2023.10
구독 인증기관 무료, 개인회원 유료
In the automotive information display device industry, products with high reliability and wide temperature conditions are required, and interest in products that do not cause lighting defects even under extremely low temperature conditions is increasing. In this experiment, we produced an LED backlight unit for car navigation in a cryogenic environment. And to make this backlight unit, we used 12 side-emitting white LEDs with 3[W] high power LEDs. This backlight unit emits up to 18,000[nits] at a power consumption of 36[W] and has a startup voltage time of less than 1[ms] at -50° ambient temperature.
3,000원
10.
2023.10
구독 인증기관 무료, 개인회원 유료
The need for lightweight yet strong materials is being demanded in all industries. Carbon fiber-reinforced plastic is a material with increased strength by attaching carbon fiber to plastic, and is widely used in the aerospace industry, ships, automobiles, and civil engineering based on its low density. Carbon-reinforced fiber plastic is a material widely used in parts and manufactured products, and structural analysis simulation is required during design, and application of actual material properties is necessary for accurate structural analysis simulation. In the case of carbon-reinforced fiber plastics, it is reported that there is a porosity of around 0.5% to 6%, and it is necessary to check the change in material properties according to the porosity and pore shape. It was confirmed by applying the method. It was confirmed that the change in elastic modulus according to the porosity was 10.7% different from the base material when the porosity was 6.0%, and the Poisson's ratio was confirmed to be less than 3.0%. It was confirmed that the elliptical spherical pore derived different material properties from the spherical pore depending on the pore shape, and it was confirmed that the shape of the pore had to be confirmed to derive equivalent material properties.
4,000원
11.
2023.10
구독 인증기관 무료, 개인회원 유료
The microstructure and mechanical properties of the heat-affected zone welded using the GTAW process on SDSS material used in offshore structures were analyzed. The chemical composition of the specimen material was analyzed using XRF. The microstructure of the heat-affected zone where the plate was welded was examined by SEM, and the ferrite volume fraction was assessed using the point count method of ASTM E562. A lot of ferrite was formed in the overheated weldment region, and In the weld cap where the cooling rate was fast, ferrite was not converted back to austenite and the microstructure was not uniform. From the ferrite phase fraction, it was shown that it can be applied to the pitting resistance equivalent numbers through changes in mechanical properties according to welding conditions.
4,000원
12.
2023.10
구독 인증기관 무료, 개인회원 유료
본 연구에서는 Monopile 방식 풍력발전기 강구조물의 부식을 방지하기 위하여 S355 steel의 표면 거칠기에 따른 용사 코팅 상태에 관한 연구를 수행했다. 일차적으로는 시편별 서로 다른 표면거칠기를 부여하기 위해 밀링머신에 페이스 커터를 결합하여 시편별로 다른 조건의 Ra값 기준 표면거칠기를 부여했다. 실험 조건으로는 시편 가공 시 4가지의 회전속도(60, 400, 1200, 2000 rpm), feed rate 150(mm/min) 조건을 선정했다. 2차로는 와이어 용융 방식의 아크 용사 코팅을 실시했다. 코팅 조건으로는 분사 거리 200mm, 전압 24V, 전류 120A, 분사 압력 5bar, 와이어 삽입 속도 30g/mm, 와이어 직경 2mm이다. 용사 코팅 후 FE-SEM으로 표면을 관찰한 결과 모든 시편의 S355 면과 코팅층(아연-알루미늄) 사이에 유격이 발생하지 않고 성공적으로 안착이 되었음을 확인할 수 있었다.
4,000원
13.
2023.10
구독 인증기관 무료, 개인회원 유료
During the initial construction of Won buddhism, the sound absorbing material and diffusion material were used in the interior of the Won buddhism, so the sound performance at each buddhism could not be secured above a certain level, and even in the case of the Won buddhism Bukil dharma hall, the reverberation and volume of the sound generated inside the sanctum was too loud, and since the establishment of the buddhism continued to be dissatisfied, the improvement of the acoustic performance was very urgent. From this perspective, this study measured acoustic performance of the Bukil dharma hall before remodeling, determined the acoustic defects and status, and used acoustic simulation to present three plans for improving acoustic performance. Taking economic feasibility, construction, and construction duration into account, remodeling was performed on the basis of Plan 1 and post-remodeling acoustic performance was measured for comparative analysis of acoustic performance between before and after the improvement. The results of study, before and after sound performance improvement sound pressure level (SPL500Hz) was 71.9dB at 79.4dB , the weighted sound level (SPLdB(A)) was 79.7dB(A) at 89.4dB(A), reverberation time (RT500Hz) was 1.12sec at 1.49sec, early decay time (EDT500Hz) was 1.39sec at 1.63sec, definition (D50,500Hz) was 34.9% at 32.3%, clarity (C80.500Hz) was 1.0dB at –0.4dB, and RASTI was 60.0%(“Good”) at 51.3%(“Fair”) was evaluated. Therefore, the Bukil dharma hall was after remodeling, neither definition(D50) improved notably but excessive volume and reverberation and sound mixing almost disappeared and acoustic performance improved so much that many different events and services could be held.
4,800원
14.
2023.10
구독 인증기관 무료, 개인회원 유료
In this study, In this study, structural analysis of a fuel tank for an SUV (sports utility vehicle) was performed for crack prevention design. Reservoir tank analysis was conducted for crack prevention design, and improvement measures for weak areas were discovered and reflected in the design. Pressure analysis was performed on the existing model to analyze weak areas. As a result of analysis through various design changes, it was found that the strength problem of the reservoir tank was due to the discontinuity of the rib inside the tank, and to improve this, it was necessary to minimize the discontinuity section.
4,000원
15.
2023.10
구독 인증기관 무료, 개인회원 유료
Recently, many countries are performing researchs about weapon systems or communication systems using laser. Because laser weapons are relatively easy to use and can exert powerful energy with high efficiency versus cost. Also laser communication systems has many advantages compared to RF communication systems, such as big data transmission through giga-bit communication, high security and so on. In these systems, one of highly important key components is Fast Steering Mirror(FSM) to control the laser beam precisely and accurately. Therefore, in this paper, we perform static and dynamic analysis to predict performances of Fast Steering Mirror using voice coil actuators. Also we manufacture prototype of FSM on the basis of static and dynamic analysis results, and perform the performance test about four items. As a result, we lay a foundation for research about FSM and laser systems, and expact to contribute improvement of performances of systems using laser.
4,000원
16.
2023.10
구독 인증기관 무료, 개인회원 유료
In this study, a vibrating nozzle using the waste vibration energy of the compressor body was installed in the suction flow path to improve the efficiency of the compressor through the pre-compression. To this end, the behavior of the suction valve according to the vibrating nozzle and the mass flow rate of the refrigerant entering the compression chamber were numerically analyzed. The results showed that the mass flow rate increased proportionally as the angle of the vibration nozzle increased. Among the profile shapes of the vibration nozzle, the concave or straight shape showed the highest mass flow rate. Considering the ease of machining, the straight shape is more favorable. On the other hand, as the operating frequency and stroke of the vibration nozzle increased, the mass flow rate also increased proportionally. It can be seen that the largest nozzle angle, operating frequency, and stroke are favorable for pre-compression unless the suction flow is restricted.. In the future, it is necessary to apply the vibrating nozzle system to an actual compressor model to experimentally check the compressor's cooling power, compression work and EER.
4,000원
17.
2023.10
구독 인증기관 무료, 개인회원 유료
The demand for LNG Carrier and LNG fuel ships are increasing due to global carbon neutrality declaration and ship emissions regulation of IMO, domestic shipyards pay technology fees(about 5~10% of ship price per vessel) to GTT company in France for making LNG cargo hold. Localization of LNG cargo hold is needed to reduce technology fees and engage technological competitiveness, it is important to secure the critical technology like automation process development of insulation system process. Especially, the automation rate of membrane-type insulation system is very low due to interference caused by corrugation and difficulty in securing optimal variable welding condition. In this study, to solve this problem, automatic welding is performed using developed automatic welding equipment on STS304L steel which is used in flat and corner area of membrane-type LNG cargo hold's lap joint. After welding, Cross-sectional observations and Tensile strength tests were conducted to evaluate reliability of equipment and welding condition. As a result of the test, it was confirmed that the strength of the welded zone exceeded that of base material, and secured the optimal welding condition to apply automatic welding.
4,000원
18.
2023.10
구독 인증기관 무료, 개인회원 유료
This paper proposes a standardized vehicle body repair manual for vehicles with major damage to the rear side members caused by rear-end collisions. The manual is used to refine the vehicles. Typical work involves replacing large traffic accident modes with new members or modifying and aligning existing members. If repairs are made for various reasons, the members should be attached based on the body of a new vehicle. Unlike new vehicle members, the accident vehicle repair process depends heavily on the operator's skilled skills (i.e., the performance, purpose, level, and quality of the body replacement work due to the nature of the vehicle body replacement work). When repairing or replacing a rear side member of a body repair, three methods of operation are applied because the damage and deformation vary depending on the object of the other party, although the degree of damage varies. There is no standardized manual for side member over-hole replacement, partial replacement, or partial modification, since these repair methods vary depending on the operator's thoughts and angle of view. Therefore, customers should use standardized vehicle repair manuals to ensure that their vehicle receives the same repair when damaged. This study is expected to develop a standardized vehicle repair manual to reduce the drop in used market prices after replacement or repair of rear side members at vehicle repair plants.
4,000원
19.
2023.10
구독 인증기관 무료, 개인회원 유료
We used Brewster’sLaw to examine the mechanism of liquid crystal(LC) alignment on anorganic insulation layer when subjected to ion-beam irradiation. Brewster’s Law implies that the maximum rate polarized ray on a slanted insulation layers on the substrate and it illustrates the dependence of polarization and the mechanical structure on the ionbeam irradiation process. The pretilt angle of nematic LCs on the organic insulation surface was about 1.13° for an ionbeam exposure of 45° for 1minute at 1800eV. This shows the dependence of LC alignment on the polarization ratio in a slanted organic insulation layer.
3,000원
20.
2023.10
구독 인증기관 무료, 개인회원 유료
In this paper, the EMP-related standards and test methods used by the civilian and military have been introduced. The incoming EMP signal for seven military RF antennas which are the first to face EMP threats among military weapon systems have been also measured and analyzed. Overall, as the applied signal strength increased, the strength of the EMP signal entering in the antenna also showed an upward trend. The highest level of entering was observed at the peak value of the applied EMP signal, 50 kV/m. And at the peak value, all antennas received threatening signals. In particular, antennas in low frequency bands such as AM and FM were getting high voltage signals as high as thousands of volts. This means that the weapon systems linked to the antennas could suffer severe damage. Therefore, based on this paper, systematic research for EMP threat should be conducted to identify EMP vulnerabilities of major weapons systems and to devise practical protective measures.
4,000원
