• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.312-315
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• 2004

A lubricated state of an automobile transmission can not be inspected directly with eyes. Thus, it needs to develop a more general method. Wear debris can be collected from the lubricants of operating transmission of an automobile and its morphology is directly related to the fiction condition of the interacting materials from which the wear particles originated in lubricated transmission. In this paper, to identify the friction condition for transmission gear by neural network, the wear test of ball-on-disk type and the analysis of friction state were carried out for carburized SCM420 and nitrocarburized NT100 under different experimental conditions. The four shape parameters($50\%$ volumetric diameter, aspect, roundness and reflectivity) of wear debris were calculated by the image processing system. They were used as input values to identify the moving condition of transmission gear by the neural network.

• Tribology and Lubricants
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• v.4 no.1
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• pp.43-55
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• 1988

A Study on the effect of the additives in lubricating oil was investigated on the basis of the thermal activated wear theory in terms of their wear behaviours, using four ballwear machine. The sample oils, which included diethyl-3, 5-di-t-butyi-4-hydroxy-benzyl phosphonate (DEP), ZDDP and TCP additives respectively, showed distinct wear characteristics depending upon the bulk oil temperature and the sliding velocity. The newly synthesized additive, viz., DEP showed excellent antiwear performance cornpared with the conventional additives, ZDDP and TCP. On the basis of the experimental results, it is reduced that the wear mechanism of the conventional additives, viz., ZDDP and TCP is the protective film formation and their antiwear capability is depending upon the shearing strength of the film formed. On the other hand, the new additive, DEP showed that the secondary activation energy was much eliminated and so, the thermal instability was reduced by the hydrogen scavenging reaction of the new additive, which was virtually an endothermic reaction process.In conclusion, a new concept of antiwear mechanism is estabilished and testified. And new chemical, which showed the function of hydrogen and free radical scavenging role, is synthesized and introduced as the new, highly antiwear effective lubricating oil additive.

• Elastomers and Composites
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• v.49 no.2
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• pp.149-154
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• 2014

Friction and abrasion behaviors were investigated for SBR rubber compounds reinforced by silica and carbon black. Knife-blade abrader, newly designed based on tearing energy theory, was utilized in order to evaluate the effect of frictional work on the wear rate of the rubber compounds. It was found that the power law relation between frictional work and wear rate worked, in which as the wear rate was increased as frictional work increased. The wear rate could be determined successfully using the knife-blade abrader in which a moving distance of the knife blade in the process of wearing was measured continuously, instead of intermittent measurements of weight loss by wear during experiment.

• International Journal of Costume and Fashion
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• v.17 no.1
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• pp.29-39
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• 2017

This study seeks to understand the consumer meanings of wearing classic styles. A qualitative research method was adopted, and 16 participants in the United States were interviewed and asked to define a classic fashion or style and why they wear one. Grounded theory was used for the research. The findings revealed three themes: (1) A classic style represents conservatism in style; (2) Style pragmatism refers to the positive attributes of wearing a classic style; and (3) consumers expect to continue to wear that classic style in the future. Those who are fashion-forward also expect to wear classic clothing in the future as they grow older. For people who do not follow fashion, classic is also a safe choice. The implications of these findings are discussed.

• Journal of the Korean Society for Precision Engineering
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• v.3 no.4
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• pp.30-42
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• 1986

On the analysis of cutting mechanics in orthogonal cutting, each cutting force component can be predicted. By adding the flank face wear term to the prediction equation for cutting force components, complete equations are obtained. Using these equations, it is shown that cutting force components are increased linearly as flank face wear land is developed, in theory and experiment. By making non-dimensional term ie. Fv/Fc, the width of variation of output signal Fv/Fc is greately decreased compared with each cutting force component as cutting condition is varied. Among these conditions, the variation of chip width in the range of more than 1mm and that of cutting velocity have little effect on the output signal Fv/Fc, that of Flank face werr land can be detected without difficulty.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.11
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• pp.93-101
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• 1997

Ever since the nonlinearity of machine tool dynamics was established, researchers attempted to make use of this fact to devise better monitoring, diagnostics and control system, which were hitherto based on linear models. Theory of chaos which explains many nonlinear phenomena comes handy for furthering the analysis using nonlinear model. In this study, measuring system will be constructed using multi-sensor (Tool Dynamometer, Acoustic Emission) in end milling process. Then, it will be verified that cutting force is low-dimensional chaos by calculating Lyapunov exponents. Fractal dimension, embedding dimension. And it will be investigated that the relation between characteristic parameter calculated from sensor signal and tool wear.

• Journal of the Korean Society for Nondestructive Testing
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• v.10 no.2
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• pp.15-22
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• 1990

Since in-core flux thimble tube wear the due to flow-induced vibration could degrade the integrity of nuclear reactor, the effective detection and interpretation of the wear is important. In order to establish an inspection technique for thimble tubes, an eddy current experiment was performed to determine the optimum test frequency, defect sensitivity and evaluation accuracy. Eddy current probes were designed and fabricated with a theory. Specimens with artificial defects were fabricated using electro discharge machining method. The results from inspection technique developed and on-site inspection showed good applicability.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.117-122
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• 2002

This study assesses the wear process of particle impingement erosion which is a major source of erosion among fluid power components. First, Bitter's theory was modified to simplify engineering calculations. Second, actual experiments were conducted to validate the modified equation. And the effect of concentration and size distribution of impinging particles was tested. Little deviation from the prediction of the modified equation was observed. To develop complete analytical approach to the erosion mechanism, further experimental data are required to establish a correlation with other engineering parameters.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.15-21
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• 2001

This study assesses the wear process of particle impingement erosion which is a major source of erosion among fluid power components. First, Bitter's theory was modified to simplify engineering calculations. Second, actual experiments were conducted to validate the modified equation. And the effect of concentration and size distribution of impinging particles was tested. Little deviation from the prediction of the modified equation was observed. To develop an analytical approach to the erosion mechanism, further experimental data are required to establish a correlation with other engineering parameters.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.10
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• pp.999-1008
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• 2007

The spacer grid set is a component in the nuclear fuel assembly. The set supports the fuel rods safely. Therefore, the spacer grid set should have sufficient strength for the external impact forces such as earthquake. The fretting wear occurs between the spring of the fuel rod and the spacer grid due to flow-induced vibration. Conceptual design of the spacer grid set is performed based on the Independence Axiom of axiomatic design. Two functional requirements are defined for the impact load and the fretting wear, and corresponding design parameters are selected. The overall flow of design is defined according to the application of axiomatic design. Design for the impact load is carried out by using nonlinear dynamic analysis to determine the length of the dimple. Topology optimization is carried out to determine a new configuration of the spring. The fretting wear is reduced by shape optimization using the homology theory. The deformation of a structure is called homologous if a given geometrical relationship holds before, during, and after the deformation. In the design to reduce the fretting wear, the deformed shape of the spring should be the same as that of the fuel rod. This condition is transformed to a function and considered as a constraint in the shape optimization process. The fretting wear is expected to be reduced due to the homology constraint. The objective function is minimizing the maximum stress to allow a slight plastic deformation. Shape optimization results are confirmed through nonlinear static analysis.