• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.113-122
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• 2018

A hydraulic breaker is an attachment of an excavator, and it crushes stones. Recently, research to reduce the impact and noise of breakers are ongoing. In this paper, a method to improve the upper, lower, and side dampers, which act as insulation for the attenuation of vibration during breaker operation, is studied through testing and simulation. To obtain the nonlinear material constants required for the simulation, the biaxial tensile test was performed with urethane, which is a material used for dampers. The existing parts and the improved parts were compared and evaluated using the LS-DYNA program. As a result, 50% of the equivalent stress was reduced in the bracket body of the hydraulic breaker, and the equivalent stress of the side damper was also decreased. We verified that the fatigue conditions were satisfied by performing a fatigue analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.31-40
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• 2012

The irregularity of railway track affects not only the comfort of ride such as noise or vibration but also the safety of train operation. For this reason, it is an interesting research area to design a reliable and sustainable railway track system and to analyze the train movement mechanism based on systematic approaches considering reasons of track irregularity possible in a specific local environment. Irregularity data inspected by EM-120, an railway inspection system in Korea includes unavoidable incomplete and erratic information, so it is encountered lots of problem to analyse those data without appropriate pre-data-refining processes. In this research, for the efficient management and maintenance of railway system, progress rate of standard deviation of irregularity is quantified. During the computation, some important components of railways such as rail joint, ballast, roadbed, and fastener have been considered. Probabilistic distributions of irregularity growth with respect to time are computed to predict the remaining service life of railway track and to be adapted for the safety assessment.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.626-633
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• 2000

An air spring which is a part of the railroad vehicle suspension system is used to reduce and absorb the vibration and the noise. Main components of the air spying are a cord reinforced rubber bellows, a upper plate, a lower plate and a stopper rubber spring. The characteristics of the air spring which are the load capacity, the vertical and the horizontal stiffness are depended on the configuration of rubber bellows, the angle of cord and the mechanical properties of cord. The computer simulation using commercial finite element analysis codes are executed to predict and evaluate the load capacity and the stiffness. The appropriate shape and cord angle of the air suing are selected to adjust the required performance of the air spring. Several samples of the air spring are manufectured and experimented. It is shown that the results by computer simulation are in close agreement with the test results.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2585-2593
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• 2011

Maglev train system has been continuously received attention as it provides good ride quality and low noise and vibration level. Furthermore it is an eco-friendly transport system with little dust pollutant. However the dynamic performance of the vehicle has been influenced by the track layout and the structural stability of guideways and girders, etc. Especially the levitation control of magnetic module is the most important performance of the Maglev system and is very sensitive about the control algorithm and the parameters of the controller. In this paper, the co-simulation of the control and dynamic model has been proposed and the simulation results for the running simulation on the curve track has been shown.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.8
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• pp.773-778
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• 2009

Chevron rubber springs are used in primary suspensions for rail vehicle. Chevron rubber spring have function which reduce vibration and noise, support load carried in operation of rail vehicle. Prediction and evaluation of characteristics are very important in design procedure to assure the safety and reliability of the rubber spring. The computer simulation using the nonlinear finite element analysis program executed to predict and evaluate the load capacity and stiffness for the chevron spring. The non-linear properties of rubber which are described as strain energy functions are important parameters. These are determined by material tests which are uniaxial tension, equi-biaxial tension and shear test. The appropriate shape and material properties are proposed to adjust the required characteristics of rubber springs in the three modes of flexibility.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.172-180
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• 1999

The major subject of this paper is to develop the concept fur a Korea high speed train system and recommend to train configuration. High speed train configurations are basically concerned traction power(train configurations with concentrated; CPT or distributed Power system: DPT) and train design(single car as compared with articulated bogies). The result of configuration, a advantages and disadvantaged were necessitated by different train configurations; -distributed underfloor power have an increased length for the seats by 15% as compared with the concentrated power trait - articulated trainsets are characterised by less of number of bogies and reduced values of mass, train resistance, noise and vibration. from the result, the optimized train concept combining high seat capacity per train length with low weight and train resistance is 400m long, single -floor train composed of two symmetrically arranged half trainsets. Therefore, at this work recommended distributed train system However, the final decision of Korea high speed train configuration was concentrated power train and articulated bogie system. The configuration of trainset was 20cars included 2 power cars, 4 motorized cars and 14 trailer cars.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.775-780
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• 2004

CWR technology is generally believed to contribute to the increase of train speed and bring a variety of significant advantages, such as the decrease in track works, noise and vibration as well as the improvement of passenger comfort. In CWR technology, welding is considered to be one of the most important element technologies. Among the various welding methods, gas pressure welding is the most frequently used in vicinity of train line station since the operation is simple and the instruments are not heavy. The gas pressure welding is constructed exactly by good manual book on which simple and excellent welding methods is written and has the same performance as raw material. But this can be poor in the variety of the processing of rail end surface to be welded, the control of oxyacetylene flame and axil compressive force. This study tries to describe the characteristics of gas pressure welding, defect-causing factors and preventive counterplan of defects

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1662-1671
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• 2008

The ERS(Embedded Rail Track system) is constructed in the world due to a slab track system having maintenance free, high structural safety, and deduction of noise and vibration. The ADRI-ERS is developed as Korean type. This paper shows that the design of ADRI-ERS and experiments according to DIN EN 13481-5 and Korea high speed train test guidelines. The ADRI-ERS has high structural safety in pull-out test, longitudinal resistance test, and fatigue test. The design method of ADRI-ERS is proposed by two design constants due to the result of experiments also.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.186-192
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• 2001

A chevron rubber spring is used in primary suspension system for rail vehicle. The chevron spring has function which support the load carried and reduce vibration and noise in operation of rail vehicle. The computer simulation using the non-linear finite element analysis program MARC executed to predict and evaluate the load capacity and stiffness for tile chevron spring. The appropriate shape and material properties are proposed to adjust the required characteristics of chevron spring in the three modes of flexibility. Also, several samples of chevron spring are manufactured and experimented. It is shown that the predicted values agree well tile results obtained from experiments.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1953-1959
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• 2011

Subway stations have a characteristic that the facilities in the ceiling should be checked, replaced and expanded frequently. The new installation of supports (steel anchors) for new facilities and workers moving-around in the ceiling result in the damage in the ceiling finish material and concrete structure which also result in construction cost increase. In addition, the noise, vibration and dust generated during the work harm the station environment. There are civil complaints on these which give difficulty to ceiling works. Accordingly, this study suggests a ceiling frame construction method that considers the convenience, economy and efficiency of ceiling work by improving the support installation method for facilities in ceiling.