• 한국기계가공학회지
• /
• 제11권5호
• /
• pp.48-53
• /
• 2012

A non-linear vehicle model and an observer are designed to observe the yaw rate and the body side slip angle when a vehicle is turning maneuver in this study. The developed vehicle model is a full car model and has fourteen degree of freedom. A Luenberg observer is applied to develop the observer. The vehicle model is validated with a reference result and shows good accordance. The observer is tested on dry asphalt, wet asphalt and snow paved road. The results prove the performance of observer is robust and reliable.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2003년도 추계학술대회
• /
• pp.66-70
• /
• 2003

Recently, environmental conscious machining becomes one of the most important technology in modern manufacturing industry. Especially in metal cutting, cutting fluid often results in many environmental problems. Many technologies have been developed to reduce the problems of the cutting fluid. But most of the technologies need another devices which sometimes require large space and also are very expensive, such as cooling system. In this paper, air compressor is only used to replace the functions of cutting fluid as semi-dry cutting. Cutting forces, cutting moments, and tool wear were measured to obtain cutting characteristics, and were compared with those of dry cutting and non-dry cutting. In the results of the experiments, semi-dry cutting was found to show better cutting performances than dry cutting and non-dry cutting.

• 한국생산제조학회지
• /
• 제24권2호
• /
• pp.211-216
• /
• 2015

Recently, because of the growth in the leisure industry and interest in health, the demand for bicycles has increased. In this research, considering the vertical load on a bike frame under static state conditions, the deflection and mass of the bike frame were minimized by satisfying the service condition and performing optimization. The thickness of the bicycle-frame tube was set to a design variable, and its sensitivity was confirmed by an analysis of means (ANOM). To optimize the solution, a response-surface-method (RSM) model was constructed using D-Optimal and central composite design(CCD). The optimization was performed using a non-dominant sorting genetic algorithm (NSGA-II), and the optimal solution was verified by finite-element analysis.

• 한국생산제조학회지
• /
• 제24권2호
• /
• pp.192-197
• /
• 2015

In many fields, the importance of reducing weight is increasing. A product should be designed such that it is profitable, by lowering costs and exhibiting better performance than other similar products. In this study, the mass and deflection of steel structures have to be reduced as objective functions under constraint conditions. To reduce computational analysis time, central composite design(CCD) and D-Optimal are used in design of experiments(DOE). The accuracy of approximate models is evaluated using the $R^2$ value. In this study, the objective functions are multiple, so the non-dominant sorting genetic algorithm(NSGA-II), which is highly efficient, is used for such a problem. In order to verify the validity of Pareto solutions, CAE results and Pareto solutions are compared.

• 대한안전경영과학회지
• /
• 제16권3호
• /
• pp.249-255
• /
• 2014

The Purpose of this study is to compare occupational accident rate of unionized and non-unionized company and to investigate influences of labor relations on occupational accident rate in Korean manufacturing and construction Industry. Data in 2011 Occupational safety and Health Trend Survey were analyzed for this study. Results show that the occupational accident rate was lower in unionized company than non-unionized company. And amicable labor relationship reduces the occupational accident rate. The policy should be needed to support labor union and improve labor relationship to prevent industrial accidents.

• 한국생산제조학회지
• /
• 제8권6호
• /
• pp.78-83
• /
• 1999

This study discusses a non-contact optical technique, electronic speckle pattern interformetry(ESPI), that is well suited for in-plane and out-of-plane deformation measurement. However, the existing ESPI methods that are based on dual-exposure, real-time and time-average method have difficulties for accurate measurement of structure, due to irregular intensity and shake of phase. Therefore, phase shifting method has been proposed in order to solve this problem. About the method, the path of reference light in interferometry is shifted and added to least square fitting method to make the improvement in distinction and precision. This proposed method is applied to measure in -plane displacement that is compared with the previous method. Also, Used as specimen AS4/PE따 [30/=30/90]s was analyzed by ESPI based on real-time to determine the characteristics of vibration under no-load and tension. These results are quantitatively compared with those of FEM analysis inmode shapes.

• 한국생산제조학회지
• /
• 제24권3호
• /
• pp.278-286
• /
• 2015

The effects of the main bearing stiffness combined with vertical non-torque force on the input load and shaft deflection of a gearbox were investigated for the three-point suspension drive train of a wind turbine. A finite element analysis model for the drive train was studied experimentally, and its applicability to the present study was verified. The results show that, as the main bearing stiffness is increased, the input load of the gearbox decreases, whereas the input shaft deflection increases. The stiffness component for the pitch moment has the largest influence on the gearbox input load. Although the gearbox life increases at a higher main bearing stiffness, the economic efficiency and durability of the entire drive train system should also be considered in the selection of the main bearing stiffness.

• 한국기계가공학회지
• /
• 제4권1호
• /
• pp.7-12
• /
• 2005

An internal finishing process by the application of magnetic abrasive finishing has been developed as a new technology to obtain a fine inner surface of pipe. In this paper, another method of magnetic abrasive machining in which the N and S magnetic poles are vibrated and a workpiece is rotated only is tried in a non-ferromagnetic pipe(SUS304), and its finishing characteristics is experimently investigated by various effective factors such as vibrating frequency and amplitude. From the experimental results, it is found that the vibration effects of magnetic poles on the finishing characteristics are large in internal finishing.

• 한국생산제조학회지
• /
• 제7권5호
• /
• pp.38-45
• /
• 1998

The Z-map model which is quite similar to the non-parametric patch is widely used to describe the shape of a surface because of its simplicity. Despite the inherent advantage of z-map model. it has drawbacks that there exists difficulty in expressing the vertical walls and its related contact treatment method. In the region of vertical walls, there is a convergence problem in searching the contact point. In this study a contact point finding scheme is presented, based on the z value of the z-map model on the sheet normal direction. To show the utility of this scheme a compared with the experimental results. The effects of the Z-map grid distances and the interpolations of the inside Z-map value are also discussed.

• International Journal of Precision Engineering and Manufacturing
• /
• 제9권4호
• /
• pp.63-65
• /
• 2008

The increased interest in reducing the environmental effects caused by releasing organic compounds and aqueous waste has motivated the development of polymeric materials in supercritical fluids. Recently, supercritical fluids have been used in material synthesis and processing because of their special properties, such as high diffusivity, low viscosity, and low surface tension. Supercritical carbon dioxide is the most attractive because it is non-toxic, non-flammable, and has moderate critical temperature and critical pressure values. Supercritical carbon dioxide can also swell most polymers. In this study, we prepared polymer/clay nanocomposites using supercritical fluids. Cloisites 10A, 15A, 25A, and 30B used in this study are montmorillonites modified with a quaternary ammonium salt. The nanocomposites of polymer/clay were characterized by X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry.