• Tribology and Lubricants
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• v.18 no.4
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• pp.305-311
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• 2002

Three different kinds of brake discs including two coated brake discs and one steel disc were tested under the same experimental conditions on a reduced scale braking test bench. A braking test bench was specially designed to analyse thermo-mechanical and frictional behaviors of two types of brake with different sizes in stop and hold braking modes. Plasma spray coating technique was also used to coat the discs with ceramic powder. During the test four commercial brake pads were coupled with discs. Ceramic coated discs showed good stability in friction coefficient at high speed and high energy braking conditions. But they caused large wear loss of pad mass compared with the steel disc. It was shown that thermal barrier effect in ceramic coated discs adjusted the thermal partition between pad and disc. For a steel disc. it showed fluctuating friction coefficient at high speed but small wear loss of pad mass compared with ceramic coated discs.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.97-107
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• 1998

Three different kinds of brake discs including two coated brake discs and one steel disc were tested under the same experimental conditions on a reduced scale braking test bench. Braking test bench was specially designed to analyse thermo-mechanical and frictional behaviors of two sizes of brake discs in stop and hold braking modes. And Plasma spray coating technique was used to coat ceramic powder on the discs. In the test four commercial brake pads were coupled with discs. Ceramic coated discs had shown good stability in friction coefficient at high speed and high energy braking conditions. But they caused large pad mass wear loss compared with the steel disc. It was shown that thermal barrier effect in ceramic coated discs adjusted the thermal partition between pad and disc. For a steel disc, it had shown fluctuating friction coefficient at high speed but a fittie pad mass wear loss compared with ceramic coated discs.

• Journal of Powder Materials
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• v.25 no.1
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• pp.30-35
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• 2018

The friction characteristics of Al-Fe alloy powders are investigated in order to develop an eco-friendly friction material to replace Cu fiber, a constituent of brake-pad friction materials. Irregularly shaped Al-Fe alloy powders, prepared by gas atomization, are more uniformly dispersed than conventional Cu fiber on the brake pad matrix. The wear rate of the friction material using Al-8Fe alloy powder is lower than that of the Cu fiber material. The change in friction coefficient according to the friction lap times is 7.2% for the Cu fiber, but within 3.8% for the Al-Fe alloy material, which also shows excellent judder characteristics. The Al-Fe alloy powders are uniformly distributed in the brake pad matrix and oxide films of Al and Fe are homogeneously formed at the friction interface between the disc and pad, thus exhibiting excellent friction and lubrication characteristics. The brake pad containing Al-Fe powders avoids contamination by Cu dust, which is generated during braking, by replacing the Cu fiber while maintaining the friction and lubrication performance.

• Tribology and Lubricants
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• v.14 no.1
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• pp.28-36
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• 1998

This paper presents the thermal behaviours of a solid type disk brake for a high-speed train. The thermal behaviours of a brake disk with 50mm thickness shows good performance compared with 45mm thickness of a disk because of a high specific heat capacity. The FEM results show that the thickness of the disk with a same weight of the brake disk should be increased for a good flexibility of the contact thermal problems. Therefore, the ratio between the pad and disk in diameter may be reduced and the thickness of a disk increased.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.3
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• pp.403-408
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• 2013

In this paper, we propose to develop an inspection system that recognizes surface cracks on the brake pad and the types of brake pads of each car during the production process, on a conveyor belt. The brake pad is made from a mixture of materials, using high-heat and pressure. Therefore, the brake pad can be cracked and damaged on the surface during production. Our goal is to develop an effective detection system and application software to detect substandard product. A shadow is generated when the artificial light shines on the damaged of the surface of pad. Using the computer vision algorithm that is proposed we can detect the substandard product. Results from experiments confrim the performance of the proposed algorithm.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.274-280
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• 2006

The study is to analyze dynamo test results for various commercial pads in order to verify the performance of brake disk with CV-NCM cast iron. The developed brake disk will apply to 200 km/h tilting trains that is being developed as one part of project for speed-up on Korean existing railroad. The test program is made out suitably for braking condition and performance of test equipment by referring UIC 541-3. Two kinds of resin pad and one kind of foreign sintered pad suitable for 200 km/h trains are used as various commercial pad for the dynamo test. The data aquisition for the maximum and smallest temperature, hot spot, etc. on disk and pad is performed by using the thermocouples and thermal imaging cameras. From this research, we obtained braking characteristics between CV-NCM cast iron disk and pad of various material and will be utilized usefully as basis data of performance optimization of developing sintered pad.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.8
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• pp.717-724
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• 2013

The present study provides the numerical results in association with caliper stiffness and friction curve. From the numerical results, it is concluded that the pad vibration modes with dominant displacement in rotation direction is sensitive in the flutter instability. Particularly, the pad rigid mode is shown to become the squeal mode when the caliper stiffness is introduced in brake squeal model. Therefore, the caliper contact stiffness between the pad and caliper is expected to contribute to the squeal modes of the brake pad.

• Tribology and Lubricants
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• v.30 no.4
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• pp.240-245
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• 2014

Low alloy heat resistant brake disk and sintered brake pad are applied to mechanical brake system for the speed-up of urban rapid transit. In this research, we analyzed how the frictional characteristics between brake disk and pad are influenced by the disk mass. At a high disk mass, the friction stability was the lower value as a result of the lack of tribofilm formation at the disk surface. Wear rates of friction materials showed the higher value at a low disk mass and wear rates of 10 mm and 15 mm showed the similar level. Average friction coefficient was the lower value at the 10 mm disk thickness and range of variation of average friction coefficient was also the smaller value at the 10 mm disk thickness. However, there were no significant changes in the friction coefficients under any of test conditions. Surface roughness of a disk showed the highest value at the 5 mm disk and surface roughnesses of 10 mm and 15 mm showed the similar level. As a result, friction characteristics of disk mass influenced the friction stability, as well as the wear rate of friction pad and disk, but not the friction coefficient.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.9-10
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• 2012

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.2
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• pp.163-169
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• 2012

The brake squeal propensity associated with friction curve is investigated by using the hybrid finite element(FE)-analytical model. The modal analysis of an actual disc and pad is conducted by FE method. Also, the modeling for the accurate contact and disc rotation is analytically achieved. The eigenvalue analysis for the hybrid model provided the squeal dependency on the friction curve. Particularly, some pad modes and the disc torsion mode are shown to be sensitive for the friction curve.