• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.31
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• pp.91-98
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• 1994

Most of machines are physically or chemically degenerated by continuous usage. There- fore, a preventive maintenance is necessary. Producing defects are caused by process shift in mean and variance which are due to three types of degeneration. We develope the function of process variance from the experimental data and determine the optimal tool wear limit and the initial setting position of tool by considering the percent defective cost and the preventive maintenance cost.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1069-1077
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• 2008

The railway abrasion measurement system have to satisfy two conditions to increase the measurement accuracy as follows. The laser region which is projected on the rail have to be extracted without the geometrical distortion. The mapping of the acquired laser region data on the rail profile have to be processed exactly. But, the conventional railway abrasion measurement system is deeply effected by the foreign substance( dust, rainwater, and so on ) on the railway or the sensitive response characteristic of the laser to the external measurement circumstance, and then the measurement errors arise from above factors. When the laser region is projected on the rail extracts from the acquired image, the interference of the light with the same frequency as the laser system occurs the serious problems. In the process of the mapping between the railway profile and the extracted laser region, the measurement accuracy is very highly effected by the geometrical distortion and the abnormal variation. In this Paper, we propose the novel method to increase the accuracy of the railway abrasion measurement dramatically. we designed and manufactured the high precision and fast image processing board with DSP Core and FPGA to measure the railway abrasion. The image processing board has the capability that the image of 1024X1280 from camera can be processed with the speed of 480 frame/sec. And, we apply the image processing algorithm base on the wavelet to extract the laser region is projected on the rail exactly. Finally, we developed high precision railway abrasion measurement system with the error range less than +/-0.5mm by which 2D image data is covered 3D data and mapped on the rail profile using the camera model and the perspective transform.

• Journal of the Korean Society for Railway
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• v.12 no.2
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• pp.230-235
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• 2009

We have conducted an experimental study to analyze characteristics of the wheel profile wear and an influence of the wheel flange wear on the vehicle's vibration characteristics. In experiment with EMU, wheel profile wear is severe at the beginning of the commercial operation. In this stage, the variations of the wheel dimension parameters and equivalent conicity is changed rapidly. Along with a mileage of the test vehicle, the wear of the wheel flange is increased and also the vibration level of the car-body is increased. The peak-peak mean value of the body vibration is estimated as good level, but the level is approached at the limit of the good level as mileage increases. Especially, the peak-peak maximum value of the body vibration shows the distinct increase of vibration level.

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.2
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• pp.196-205
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• 2024

In this study, sample collection and quantification analysis of Tire and Road Wear Particles (TRWP) from the road surface were conducted to predict the amount of TRWP generated on the road surface moving by environmental compartment depending on rainfall intensity. Samples were collected from TRWP remaining on the road surface two days after the 3 days average rainfall (0-60 mm/day) occurred and the road surface was completely dry. Only TRWP were separated from the collected samples through size and density separation, and the difference in the content of TRWP remaining on the road surface after rainfall was based on the value of 60.2 g o f TRWP o n a day witho ut rain (0 mm/day). By calculating, it was co nfirmed that 0-49.4 g o f TRWP can mo ve to the environmental compartment depending on the intensity of rainfall. In addition, it was confirmed that when the rainfall intensity was 60 mm/day, the amount of TRWP moving to each environmental section was 3.75 times higher compared to 5 mm/day, and using the results of previous research, the total amount of TRWP that can be transported to the environmental compartment by rainfall from the domestic road environment annually is 9,592 tons, and 288 tons of this can be affected by marine microplastics. However, this study has limitations in terms of limited space and predicted results, but it would like to mention the need to improve the domestic road environment and sewage treatment system to reduce TRWP. In the future, we plan to conduct sample collection and concentration analysis studies of TRWP in real environmental compartments to verify the results of this study.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.3
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• pp.281-301
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• 2024

The power cable tunnels which are part of the underground transmission line project, are constructed using the shield TBM method. The disc cutter among the shield TBM components plays an important role in breaking rock mass. Efficient tunnel construction is possible only when appropriate replacement occurs as the wear limit is reached or damage such as uneven wear occurs. A study was conducted to determine the wear conditions of disc cutter using a deep learning algorithm based on real-time measurement data of wear and rotation speed. Based on the results of full-scaled tunnelling tests, it was confirmed that measurement data was obtained differently depending on the wear conditions of disc cutter. Using real-time measurement data, an algorithm was developed to determine disc cutter wear characteristics based on a convolutional neural network model. Distributional patterns of data can be learned through CNN filters, and the performance of the model that can classify uniform wear and uneven wear through these pattern features.

• Journal of Biomedical Engineering Research
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• v.25 no.2
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• pp.157-163
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• 2004

Nitrogen ion implantation and ion plating techniques were applied for improvement of the wear resistance of metallic implant materials. In this work, the wear dissolution behaviour of a nitrogen ion implanted super stainless steel (S.S.S, 22Cr-20Ni-6Mo-0.25N) was compared with those of S.S.S, 316L SS and TiN coated 316L SS. The amounts of Cr and Ni ions worn-out from the specimens were Investigated using an electrothermal atomic absorption spectrometry. Furthermore, the Ti(Grade 2) disks were coated with TiN, ZrN and TiCN by use of low temperature arc vapor deposition and the wear resistance of the coating layers was compared with that of titanium. The chemical compositions of the nitrogen ion implanted and nitride coated layers were examined with a scanting auger electron spectroscopy. It wat observed that the metal ions released from the nitrogen ion implanted S.S.S surface were significantly reduced. From the results obtained, it was shown that the nitrogen ion implanted zone obtained with 100 KeV ion energy was easily removed within 200,000 revolutions from a wear dissolution testing under a similar load condition when applied to artificial hip joint. The remarkable improvement in wear resistance weir confirmed by the nitrides coated Ti materials and the wear properties differ greatly according to the chemical composition of the coating layers. for specimens with the same coating thickness of about 3$\mu\textrm{m}$, TiCN coated Ti showed the highest wear resistance. However, after removing the coating layers, the wear rates of all nitrides coated Ti reverted to their normal rates of below 10,000 revolutions from Ti-disk-on-disk wear testing under the same load condition. From the results obtained, it is suggested that the insufficient depth of the 100 Kel N$\^$＋/ ion implanted zone and of the nitrides coated layers of 3$\mu\textrm{m}$ are subject to restriction when used as frictional parts of load bearing implants.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.35
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• pp.9-16
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• 1995

The degeneration of tool in material removal processing machinery can be characterized by wear, deflection, chattering and any failure in tool or in the material In be processed. In the previous studies, first three of them are analyzed as a preventive maintenance strategy in quality control area. The last of them, any failure, is analyzed as a preventive maintenance strategy in reliability area. In this research, we propose a simple integrated mathematical model which minimizes the cost of machinery failures and producing defects. We determine the optimal wear limit of tool by considering the percent defects. cost, the preventive maintenance cost, and the corrective maintenance cost.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.533-539
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• 2010

The The contactless railway abrasion measurement system have to satisfy two conditions to increase the measurement accuracy as follows. The laser region projected on the rail have to be extracted without the geometrical distortion. The mapping of the acquired laser region data on the rail profile have to be matched with the cross section of rail, exactly. But, the conventional railway abrasion measurement system is required the post image processing with a camera model and a perspective transform for the exact mapping between the cross section of rail and the coordinate data extracted from a line laser region or the raw image obtained from a camera because the image captured from the camera has an oblique viewpoint. So, the measured rail profile data had limits to the measurement accuracy because of a discontinuity point. In this Paper, we propose the 3D rail profile reconstruction method to increase the accuracy of the railway abrasion measurement system applying the modified camera model and perspective transform to the image obtained from the bidirectional rail.

• 기계와재료
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• v.21 no.4
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• pp.16-22
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• 2010

고온에서의 내열, 내산화, 내부식 등의 한계성을 극복하기 위하여 새로운 고온재료의 개발과 함께 표면특성 향상을 위한 코팅기술에 대한 연구가 계속 되어 왔다. 현재 선진국에서는 C/C복합재료를 비롯하여 $Si_3N_4$, SiC 및 SiC/SiC계 CFCC등의 규소계 비산화물 세라믹재료 등에도 표면에 내식, 내마모, 열차폐 및 내산화성에 견딜 수 있는 코팅층을 형성시켜, 표면에서의 산화, 열응력, 및 내산화성 등에 대한 특성평가 및 최적의 코팅층에 대한 연구가 진행중에 있으며 향후 국내에서도 육성해야할 중요한 기술분야이다.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.110-117
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• 2019

Purpose: This study was to evaluate the wear resistance of 3D printed, milled, and conventionally cured provisional resin materials. Materials and methods: Four types of resin materials made with different methods were examined: Stereolithography apparatus (SLA) 3D printed resin (S3P), digital light processing (DLP) 3D printed resin (D3P), milled resin (MIL), conventionally self-cured resin (CON). In the 3D printed resin specimens, the build orientation and layer thickness were set to $0^{\circ}$ and $100{\mu}m$, respectively. The specimens were tested in a 2-axis chewing simulator with the steatite as the antagonist under thermocycling condition (5 kg, 30,000 cycles, 0.8 Hz, $5^{\circ}C/55^{\circ}C$). Wear losses of the specimens were calculated using CAD software and scanning electron microscope (SEM) was used to investigate wear surface of the specimens. Statistical significance was determined using One-way ANOVA and Dunnett T3 analysis (${\alpha}=.05$). Results: Wear losses of the S3P, D3P, and MIL groups significantly smaller than those of the CON group (P < .05). There was no significant difference among S3P, D3P, and MIL group (P > .05). In the SEM observations, in the S3P and D3P groups, vertical cracks were observed in the sliding direction of the antagonist. In the MIL group, there was an overall uniform wear surface, whereas in the CON group, a distinct wear track and numerous bubbles were observed. Conclusion: Within the limits of this study, provisional resin materials made with 3D printing show adequate wear resistance for applications in dentistry.