• 한국정밀공학회지
• /
• 제21권12호
• /
• pp.146-153
• /
• 2004

We compared the fatigue characteristics of weld metal with those of base metal, and not heat-treated with heat-treated. Also, we examined the influence of bead in a viewpoint of fatigue life. From the experimental results, it has been seen that the fatigue characteristics of welded specimens grinded the toe of bead are slightly better than not grinded. We have seen that the fatigue life is affected more by the stress concentration on the profile change in the weld toe rather than by residual stress influence, because heat-treated or not had almost no influence on the fatigue characteristics.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2001년도 추계학술대회 논문집
• /
• pp.235-239
• /
• 2001

The bogie of high speed freight car running on conventional line is welded bogie modeled on Y25 bogie developed in Europe. Y25 bogie has speed limit of 110km/h. But it has limiting factors to speed-up as increasing maintenance cost and friction parts pedestal. And also it was reported that cracks are found in the parts where center beam meet bolster and endbeam near bracket for braking part. This study includes stress analysis improved structure of welded bogie for strength evaluation by numerical method and experimental method. According to the study, new configuration bogie shows improvement in strength.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2001년도 춘계학술대회 논문집
• /
• pp.217-221
• /
• 2001

Barber bogie and Y25 bogie is the main bogie of freight car which is used in the Korean railway. In case of Barber bogie and a mixed formation tile maximum speed limit of empty car is 70 km/h and that of loaded car is 90 km/t and also it runs a speed of 110 km/h in time of an exclusive formation of Y25 bogie. The car named as high speed freight car at present is Y25 bogie which modeled on the Y25 bogie or Europe developed in 1993, Y25 bogie has no problem about the running capacity up to the speed of 110 km/h, but it works as limiting factors to tile increasing cost of maintenance and repair expenses which caused by repair of bogie and the cost of materials. This study is going to describe the contents examined by analysis and tests, aimed at being used as an index of plan in the future through the strength test of high speed freight car which is used now.

• 대한기계학회논문집A
• /
• 제36권8호
• /
• pp.921-927
• /
• 2012

신뢰성 기반 최적설계는 설계변수들의 변동을 평균이나 분산 등의 통계적 특성으로 고려하여 설계자가 원하는 신뢰도를 만족하는 해를 구한다. 신뢰도를 구하기 위한 기존의 신뢰성해석 기법들은 변수들이 연속함수로 정의되는 특정 확률분포를 따른다는 가정을 하지만 실제 문제에서 변수들은 한정적인 이산정보의 형태인 경우가 많기 때문에 변수들에 대한 가정을 하지 않고 이산정보로부터 신뢰성해석을 수행하는 것은 매우 중요하다. 본 연구에서는 후보 분포들 중에서 이산정보를 가장 잘 추정하는 분포를 결정하는 기법인 Akaike 정보척도를 이용하여 신뢰성해석 및 신뢰성 기반 최적설계를 수행하는 기법을 제안한다. 수학예제를 통해 정확성을 검증하고 철도차량 용접대차의 신뢰성 기반 최적설계에 적용하여 제안한 기법의 유용성을 확인한다.

• 한국정밀공학회지
• /
• 제32권7호
• /
• pp.619-625
• /
• 2015

There is a large interest to find reliable and automatic methods for crack detection and quantification in the railway bogie frame. The non-destructive inspection of railway bogie frame has been performed by ultrasonic and magnetic particle testing in general inspection. The magnetic particle method has been utilized in the defect inspection of the bogie frame but the grinding process is required before inspection and the dust is developed resulting from the processing. The objective of this paper is to apply the inspection method of bogie frame using infra-red thermography. The infra-red thermography system using the excitation of eddy current was performed for the defect evaluation of weld specimen inserted artificial defects. The result shows that the infra-red thermography method can detect the surface and inner defects in weld specimen for bogie frame.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2004년도 춘계학술대회 논문집
• /
• pp.726-731
• /
• 2004

Bogie is the connection device between carbody and wheel in railway vehicles. It is the core part that exert a important effect on the passenger safety and running safety. Bogie largely consists of bogie frame, suspension, brake, wheel set. Static and Dynamic load have acted on it complexly. When the bogie is designed, finite element method, static load test, fatigue test, running test should be considered. Some bogie frame of high speed railway freight car have the problem. It's end beam was cracked. The crack of the end beam have a bad effect on brake system. In that case, the cars would be in danger of derailment.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2004년도 춘계학술대회 논문집
• /
• pp.859-864
• /
• 2004

In this study, we compared the fatigue characteristics of weld metal with those of base metal. Also we examined the influence of heat treatment and weld bead profiles for the fatigue life of weld metals. From the experimental results, it was seen that the fatigue characteristics of welded specimens with a grinded toe of bead are slightly better than those are not grinded. Also the fatigue life is affected more by the stress concentration on the profile change in the weld toe rather than by residual stress influence, because the fatigue characteristic of weld metals was not influenced whether the heat treatment is conducted or not.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2007년도 추계학술대회 논문집
• /
• pp.830-835
• /
• 2007

In this paper, stress analyses using shell and solid elements on weld zone of railway bogie frame were performed. To calculate stress distribution on weld zone, a coupling model using shell and solid elements was suggested. For this purpose, we performed specimen analyses on T-type solid and shell model of T-type panels which were modeled using shell elements, solid elements and coupled elements, respectively. The result showed that the stress concentration at weld zone was occurred in solid model, but it didn't occur in shell model. And the stress distribution of coupled model was similar to that of solid model. Also, we applied the coupled modeling method on the analysis on weld zone of bogie frame. The stress distribution of coupled model showed much higher compared to that of shell only model. Therefore, the coupled model method is highly recommended for the stress analysis in weld zone of bogie frame.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 춘계학술대회 논문집
• /
• pp.2230-2235
• /
• 2008

As a consequence of the standardization process developing in Europe, on April 2005 the new European standard EN 13749 was issued by the European standardization body CEN. The norm EN 13749 standardizes and develops the requirements already present in UIC leaflets for test verifications and define all technical requirements for the acceptance process in order to achieve a complete satisfactory design of the bogie. The aim of the norm is to define the complete design process of new railway bogies. It includes design procedures, assessment methods, verification and manufacturing quality requirements. In this study, fatigue analysis of the bogie frame is investigated comparing different approaches between conventional methodology and simulation results based on the VPD(Virtual Product Development).

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2003년도 추계학술대회 논문집(III)
• /
• pp.103-108
• /
• 2003

Among welded structure bogies in use for high speed freight car, a part of bogies manufactured in 1999 and 2000 have found problems that failure occurs in its end beam. In case of a freight car a difference of weight between empty and loading conditions are worse than in case of a passenger car. Moreover its brake system is tread brake without second suspension system. A failure of end beam is supposed to be due to loading by brake rather than vertical loading by freight. This failure can make brake system useless and may be a cause of derailment in the worst case. In this study, in order to be proved the cause of failure and to solve the problem it is described that we have measured load history acted on end beam and set up the procedures.