In this study, a numerical analysis was performed as steady-state analysis to investigate the effect of interference between the propellers of the hexa-copter. As the distance increases, there is little change in thrust, but when a propeller close to the reference propeller rotates, it was confirmed that the thrust decreased due to the interference effect. Unsteady state analysis was performed to confirm the influence of the hexa-copter fuselage. If there is a fuselage, the thrust was predicted to increase by about 4.97% due to the ground effect. If the design parameters are established considering the effect of the fuselage of the hexa-copter, it is expected to be used for basic design and application design in the future.
In this study, the noise reduction effect of the steam vent silencer was investigated by performing a transient flow analysis applying the Loss Model, a porous flow analysis model, and calculating the noise intensity from the pressure fluctuation according to the time change. As a result of flow analysis, it was confirmed that the noise intensity decreased as the number of diffusers and the number of splitters made of foamed aluminum increased. In the case of three-stage diffusers, the noise intensity decreased by up to 33.4 dB when six foamed aluminum with a thickness of 150mm were installed.
In this study, 3D design, vibration analysis and experiment, and feed rate performance test were performed to develop a vibratory bowl feeder for supplying ultra-thin plate parts of less than 50 microns. The natural frequency and resonant frequency of the vibratory bowl feeder were obtained through the vibration analysis and experiment, and it was confirmed that the results of the analysis and experiment agree well. Through the feed rate experiment, it was confirmed that up to 610 ultra-thin parts per minute were fed at 250Hz and a supply voltage of 220V, where the excitation frequency and the resonant frequency match. And through analysis and experimental research, it was confirmed that the development of a vibratory bowl feeder for supplying ultra-thin parts was successful.
This research was conducted for dewatered sludge cake of industrial wastewater treatment, i.e., as the object of inorganic sludge discharged especially in iron & steel manufacturing shop which used Air drying system to reduce water content. That drying system's single-type cyclone separator was confirmed to have significantly lower separation efficiency on the conditions 20μm and below of particular size through computational fluid dynamics(CFD) analysis. However, we found out the primarily advanced value of separation efficiency on dual-type directly connected. Regarding separation efficiency on size of 10μm, the efficiency of a single-type was presented at 51.91%. On the other side, the efficiency of the dual-type was 97.88%. This advanced effect of the dual cyclone separator was checked at a demo facility of air drying equipment designed by 340m3/min of airflow on site.
This thesis relates to developing an index drilling automation system that quickly and efficiently processes a hole in a product by a rotating robot arm and transfer devices. Static structural analysis was performed using the ANSYS Mechanical program to evaluate the structural stability of the system. According to the research, the equivalent stress value is low overall, and the minimum safety factor is 4.42, so it seems structurally safe. This system will significantly help improve productivity through unmanned work as it can control and set the drill and index simultaneously on the control panel in conjunction with the training.
This paper is about structural, and vibration analysis for the development of Index chucks Structural and vibration analyses were performed using the ANSYS Mechanical program to evaluate the Index chuck's structural stability and vibration characteristics. As a analysis result, when the maximum load of 500N was applied to the Index chuck, the safety factors were 2.06, 2.09, and 2.60, respectively, when the thickness was 5mm, and the outer diameters were 70mm, 90mm, and 120mm, respectively. Structurally safe results were obtained. In addition, under load conditions of 300 N or less, structural safety was confirmed if the thickness is 3mm or more.
목적 : 소음으로 인한 스트레스가 다양한 시기능에 미치는 영향에 대해 알아보고자 하였다.
방법 : 안과적 질환, 수술이력 및 안구운동에 이상이 없는 젊은 성인 60명(23.12±1.26세)을 대상으로 하였으며 소음에 노출되기 전, 후로 지각된 스트레스 척도, 최대조절력, 조절반응량, 원-근거리 사위량, 비침습적 눈물 막 파괴시간의 변화를 관찰하였다.
결과 : 소음 스트레스에 노출이 된 후에는 지각된 스트레스 척도는 증가하였다. 푸쉬업 및 마이너스렌즈 부가 법으로 측정된 최대조절력과 조절반응량은 감소하였고, NITBUT 역시 감소하였으며, 원-근거리 사위량은 증가하는 경향을 나타내었다.
결론 : 본 연구의 결과를 통해 소음 스트레스는 시기능에 다양한 형태로 영향을 미치고 있다고 볼 수 있으며, 굴절검사 및 시기능 평가 시 주변 환경에 의한 소음 스트레스가 작용하지 않도록 검사실 환경을 구성하는 것이 중요할 것이라 사료된다.
This study was performed to analyze the effect on driving performance by identifying the flow characteristics of the rear diffuser such as drag coefficient, lift coefficient, velocity vector, velocity streamlines, turbulence kinetic energy and vortex-core region according to the angle of the sedan rear diffuser and the shape of the divider. The angle of the diffuser was analyzed at 2° intervals from 0° to 18°, and the divider was analyzed by changing from one to five. The three-dimensional modeling was performed using CATIA V5 and the vehicle model was selected as a sedan car in the form of an LF Sonata. The CFD analysis was performed in order to identify the flow characteristics of rear diffuser using ANSYS CFX 14.5.7. For each model, the analysis was performed under each condition with speeds of 80km/h, 100km/h, 120km/h, 140km/h. The results of the flow analysis showed that the rear diffuser angle was the best result in driving stability at 6°. The results of the study on the number of dividers showed the best result value in driving stability when the rear diffuser angle was 6° and the divider was 3 and selected as the optimal shape.
There are many disadvantages to existing silencers used in power plants. Recently, high-performance silencers are required in society, so it is necessary to develop silencers accordingly. Therefore, in this study, to develop the flow silencer by taking advantage of the foamed aluminum, the property values such as loss coefficient and porosity were obtained through experiments, based on the Forchheimer's law. CFD analysis was performed by applying a porous modeling technique to foamed aluminum and the results were compared with experimental values. The error rate between the results of the experiment and the flow analysis is within about 2.79%, so the results of the experiment and the analysis agree relatively well. When the foamed aluminum was installed, the flow noise was reduced by about 5.14dB.
The tubular link chain conveyor works under very extreme conditions such as high tensile load, friction, and dangerous operating environments. In this study, we propose an optimal design plan for reducing cost and improving performance through weight reduction of tubular link chain conveyors for sludge transport. For light weight of tubular link chain conveyor, the optimization software using SHERPA algorithms, HEEDS was used in conjunction with ANSYS Mechanical V14.5, which is widely used in structural analysis, to achieve optimal tubular link chain. Through the optimization process, 19% light weight was achieved.
A study on the weight reduction of a motor shaft in electric vehicle by using optimum design technique was carried out. The structural analysis of a motor shaft was performed by using ANSYS to investigate the structural safety. We also used HEEDS to find the optimal hollow shaft thickness. When the material of the hollow shaft is changed to SCM822H by using ANSYS 14.5 and HEEDS MDO, the weight could be reduced by about 53 % compared to the conventional solid one. From this study, the optimized dimensions of a hollow shaft were determined for light weight design.
In this study, the TRIZ methods were used to solve the main cause of the ink splashing phenomenon in a tattoo machine. To solve the ink splashing phenomenon that occurs when a tattoo machine is operated, a flow analysis of the needle unit was performed using ANSYS CFX V14.5. From the flow analysis result, it was confirmed that the ink splashing phenomenon of the tattoo machine can be supplemented by the hole leading to the outside to the needle unit of a tattoo machine. In order to diagnose the natural frequencies of the tattoo machine and the resonance phenomenon caused by the excitation of the motor, the natural frequency analysis was performed using the Abaqus/standard frequency analysis technique. From the results of the natural vibration analysis, it was confirmed that no resonance occurred. It is expected that it will contribute to improve the efficiency of the semi permanent cosmetic device with removable ink cartridge.
Currently, the cutting oil supply device is not equipped to cool the cutting oil. Therefore, additional cooling device should be connected to cool the cutting oil. This has the disadvantage of increasing the size of the device and reducing its cooling capability. To overcome these shortcomings, cooling coils are applied to the outside of the cutting oil filtering device to develop a heat exchanger filter for simultaneous coolant filtering and cooling to improve the compactness of the cutting oil supply device and cooling capability of the cutting oil. For the development of heat exchanger filter, flow and heat transfer analysis were performed. Due to the small heat transfer area of 10 cooling coils, less heat exchange occurred. In the 20 cooling coils, the coolant cooling coils prevented smooth flow of the cooling oil in the heat exchanger filter. The cooling efficiency of the 15 cooling coils were best, and the cooling temperature decreased non-linearly as the supply flow rate of the cutting oil increased.
As the demand for high-speed and high-precision machining increases, the need for cooling and filtering of cutting oil is high. A new concept of coolant heat exchange filter is developed by installing cooling coil through which refrigerant(R410-a) passes through the coolant filtering device. For structural safety evaluation of the heat exchanger filter for cutting oil suppling device of machine tool, thermal stress and vibration analysis were performed using ANSYS program. The results of structural and thermal stress analyses have led to the conclusion that the cooling system has structural stability. From modal analysis, first natural frequency is 12.37 hz and deformation is 22.041 mm. Sixth natural frequency is 26.887 hz and deformation is 25.563 mm.