• 한국기계가공학회지
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• 제13권6호
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• pp.111-118
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• 2014

Aluminum lithium alloys are new materials developed for lightweight aircraft parts. However, as compared with conventional aluminum alloys in high-speed machining, problems such as tool wear, machining distortion, and cutting ability arise. This study presents the machining distortion characteristics of an Al-Li alloy wing tip in relation to the cutting heat in high-speed machining. A machining experiment was conducted with high-speed machining equipment for an evaluation of the machining distortion characteristics, with each machining stage temperature change of the workpiece machining surface, and the inside and outside temperature changes of the equipment measured. By measuring the amount of distortion of the workpiece before and after machining, the cutting heat was analyzed with regard to its effect on machining distortion in the product.

• 한국기계가공학회지
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• 제16권6호
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• pp.35-40
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• 2017

The aerodynamic performance of airplane is different according to the configuration of landing gear. As the drag becomes different according to this configuration, the flow stream of air must be smooth at taking off and landing. In this study, the configuration of landing gear was designed each in order to enhance the energy efficiency of airplane. Five models were compared in total at analysis. The magnitudes of drag and pressure became different and the air pressure of wake were changed due to the configuration. So, the air pressure due to the flow velocity and the air resistance happening at the rear can be estimated according to the configuration of landing gear. It is thought to improve the performance of airplane through the result of this study.

• 대한안전경영과학회지
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• 제7권2호
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• pp.85-94
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• 2005

The purpose of this study is to execute the investigation of injurious factors causing muscle-skeletal diseases at an automotive glass manufacturing company and, on the basis of the results, to enhance productivity by the improvement of working environment. By using an survey and an ergonomic evaluation method, symptoms of muscle-skeletal diseases of workers and working postures at each process were analyzed, and quantitative evaluation of muscle-skeletal disease risk against each process was performed. Based on the result of the evaluation, to enhance the working environment, improvement of worktable, working space, tools, and outfit was suggested, and induction of mechanical system was also suggested. Suggested improvement plan was applied to the workplace step by step and it is confirmed that improvement plan not only removes the injurious factors of muscle-skeletal diseases but also is effective to enhance productivity.

• 한국기계가공학회지
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• 제18권9호
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• pp.17-22
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• 2019

A ship's propulsion system is a device to move the ship by means of the power transmitted from the ship's engine to the propeller. In this study, three propeller models, a, b, and c, are designed and their flows are analyzed. Same flows with the same material are applied to all three models. Flow analysis results differ according to the shape of flow model though these models are the same material. In all respects, model C is considered to be more rigid and efficient than models A and B. A propeller model optimized for the driving force and stability can be developed through this study result.

• 한국기계가공학회지
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• 제18권9호
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• pp.23-28
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• 2019

In this study, flow analysis results according to different air cleaner and resonator configurations were used to investigate flow and velocity. Among models A, B, and C, model B had the higher speed and pressure. Model B is therefore considered suitable as an air cleaner. This study aims to design optimal shapes of air cleaners and resonators without noise sources.

• 한국기계가공학회지
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• 제18권10호
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• pp.1-7
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• 2019

Most of people are riding on their own bicycle due to the health and environmental pollution problems. The weight must be light in order to run farther and easier by bicycle. The durability will be reduced due to the light weight of tubes and handles at bicycle. To solve this problem, the three bicycle handle models 1, 2 and 3 were compared with each other for structural analysis. The structural analysis was carried out in this study. Among three models, model 2 and model 3 had the highest and lowest strengths at the structural analysis results, respectively. At this study result, model 1 is thought to be the balanced excellent model with no defect among three models.

• 한국기계가공학회지
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• 제18권8호
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• pp.18-23
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• 2019

In this study, structural and fatigue analyses of the motor gears that control the height of car seat were carried out at angles of $10^{\circ}$, $20^{\circ}$, and $30^{\circ}$. The study aims at examining which angle of the gear is superior in terms of effect on strength. In the structural and fatigue analyses, the force of 3136 N was applied to the gears, and the stress and deformation were obtained. As the analysis results, model B ($30^{\circ}$) is suggested to have the best strength and fatigue durability among the three models.

• 한국기계가공학회지
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• 제20권12호
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• pp.107-112
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• 2021

The usage of electric-powered components consisting of several electrical and mechanical parts is continuously increasing in automobiles. Therefore, continuous assessment of the reliability and quality of these electric-powered parts is crucial. In this study, a noise and vibration measurement system for testing and evaluating the different electric-powered parts of automobiles was designed. Further, an FFT analysis was performed on some electric-powered steering assembly test equipment. In the FFT analysis of the noise and vibration signals for each essential fault part, the vibration FFT analysis was significantly compared with the noise analysis. The results showed that the vibration FFT analysis was more effective in determining the reliability and quality of the electric-powered parts.

• 한국기계가공학회지
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• 제17권5호
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• pp.91-96
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• 2018

The oleophobic property of surfaces modified with micro-post structures are investigated for a range of micro-post diameter ($11-23{\mu}m$) and pitch ($20-40{\mu}m$). The contact angle of an oil droplet on surfaces with various micro-post dimensions was calculated using the Cassie-Baxter model and did not show a good agreement with the measured contact angle. From measurement, the micro-post with diameter of $23{\mu}m$ and pitch of $32{\mu}m$ was found to have the highest contact angle ($134.3^{\circ}$).

• 한국기계가공학회지
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• 제18권3호
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• pp.49-58
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• 2019

Automatic transmissions are standard equipment in most automotive vehicles because they provide smooth speed shifting and a compact design with multiple speed ratios. Their structure consists mainly of planetary gear sets as power-transmitting devices and brakes and clutches as shifting devices. Several forward and one reverse speed ratios are achieved by actuating shifting devices to connect gears, input and output shafts, and the transmission case. In the development of a new transmission, kinematic configurations reflecting the transmission concept design are required, and the ability of the new concept design to be assembled without any interference among the connections must be demonstrated. In this study, an assemblability analysis of the kinematic configurations of a Ravigneaux-type automatic transmission was conducted with an assemblable example of an 8-speed Ravigneaux-type automatic transmission.