• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.87-87
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• 2004

최근 철도 차량은 안전성, 정시성, 대량 수송성이 우수하여 수송수요가 증가하고 있으며, 열차운행 횟수의 증가와 차량의 고속화로 운행조건이 가혹해짐에 따라 이에 대한 절대적인 안전성과 높은 신뢰성이 요구되고 있다. 철도차량과 같이 반복하중이 연속적으로 작용하는 구조물의 설계에 있어서는 구조물의 사용 환경이나 재료의 피로특성을 최우선의 고려사항으로 간주해야 한다. 실제로 철도차량의 대차 프레임은 맞대기 용접으로 제작되어 있으며, 용접부에서 파손이 발생하고 있다.(중략)

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.832-835
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• 2011

최근까지 용접구조물의 피로설계는 용접품질 수준에 따라 공칭응력 또는 핫스팟 응력에 의한 S-N선 도로부터 수행하였다. 본 연구에서는 유한요소망의 크기에 덜 민감하면서 기존의 하중모드형식, 두께 효과 및 용접결합형식에 상관없는 등가구조응력(E2S2) 접근법을 이용한 Master S-N선도로부터 철도차량 대차프레임의 피로수명을 평가하고자 한다. 또한 합리적인 철도차량 용접대차프레임의 피로해석 연구일환으로서, 다축피로조건인 EN규격의 피로시험조건하에 이의 피로수명을 평가하고자 한다.

• Journal of the Korean Society for Railway
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• v.18 no.4
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• pp.301-308
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• 2015

To reduce the weight of a railroad vehicle, a bogie frame skin is considered for manufacture using an RTM process and composite material. Compared to other processes, RTM has merits in that it demands only simple manufacturing facilities and can produce a large and complex structure in a short cycle time. On the other hand, it is important to determine the proper number and locations of gates and vents to prevent void formation inside a structure. In this study, we numerically predicted the flow pattern in a bogie frame skin during the RTM process by distinguishing the permeability of a fiber mat as isotropic or anisotropic. Using the results, we analyzed the RTM process conditions of the bogie frame to predict skin void formation, mold filling time, and optimum location of vents depending on the permeability conditions.

• Composites Research
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• v.23 no.6
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• pp.19-25
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• 2010

This paper describes the optimum design of bolt locations for metal joint parts of railway bogie frame made of glass fiber/epoxy 4-harness satin woven laminate composite and PVC foam core. The optimum design analysis was done by sub-problem approximation method using Ansys Parameter Design Language(APDL). The sub-modeling method was introduced to conduct the detailed recalculation for the only target parts and reduce calculating time. The structural analysis for composite bogie frame was performed according to JIS E 4207. The results showed that the optimum design analysis using sub-modeling method was able to obtain faster and more precise results than that of the entire model by the control of mesh size for the target parts, and the maximum Von-Mises stress has been reduced in comparison with its original dimensions due to the optimum design of bolt locations.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.109-115
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• 2012

In order to evaluate the effect of structural degradation of a GFRP composite bogie frame due to ballast-flying phenomena, the impact test and residual compression test after impact was conducted for glass fiber/epoxy 4-harness satin woven laminate composites applied to skin part of a bogie frame. The impact test was performed using a instrumented impact testing system with energy levels of 5J, 10J, and 20J, and the impactor was designed to have various ballast shapes such as sphere, cube, and cone to consider the ballasted track environments. The residual compression strength was tested to evaluate the degradation of mechanical properties of impact-damaged laminate composites. The results showed that the damage area and the degradation of residual compressive strength after impact for laminate composites was increased with increase of impact energy for all ballast shapes, and was particularly most influenced by ballast shape of cone.

• Journal of the Korean Society for Railway
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• v.8 no.4
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• pp.321-329
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• 2005

This paper has established the strength evaluation procedure of the bogie frame for the Korean tilting train that is being developed in KRRI, In order to establish the strength evaluation procedure, firstly, the loading conditions imposed on the tilting train were investigated. In addition, the static and fatigue strength of the bogie frame has been evaluated. In order to derive the dynamic loads according to the carbody tilting, the load redistribution effect by carbody tilting, the unbalanced lateral acceleration effect by high-speed curving and the tilting actuator force effect have been considered. Multi-body dynamic analyses have been carried out to evaluate the tilting load cases and the strength analysis has been performed by finite element analyses. From this study, the structural safety of the bogie frame could be ensured.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.161-165
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• 2001

Bogie frame of the electric car is an important structural member for the support of vehicle loading. In general, more than 25 years' durability is necessary. Much study has been carried out for the prediction of the structural integrity of the bogie frame in experimental and theoretical domains. One of the useful methods is reliability-based approach. The objective of this paper is to estimate the structural integrity of the bogie frame of an electric car, which is under the running test. We used two approachs. In the first approach probabilistic distribution of S-N curve is used. In the second approach, limit state function is used.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.145-151
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• 2016

We consider the position and thickness of reinforcement with respect to fatigue fracture of welded bogie frames and propose an appropriate reinforcement method for many cases. The bogie frame is usually designed in accordance with JIS and KS, and operates under harsh load conditions: dynamic loads generated while driving, various loads during operation, and large load differences between loading and unloading. Consequently, fatigue failure often occurs throughout the bogie frame. We modelled the reinforcing method using ANSYS software and reviewed stress in the vicinity of common fatigue failure sites through computer simulation, optimizing the position and thickness of reinforcement.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.765-770
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• 2014

This paper describes the study on a method for improving the structural durability of bolted joints applied to a composite bogie frame. In this study, three bolted joints with and without inserts and screw threads were selected for determining the effect of the inserts, using experiment and analysis. The structural performances of the proposed bolted joints were compared and evaluated using the test method prescribed by the ASTM D5961 standard. The results revealed that the bolted joint having an insert shape without the screw thread offered improved durability for application to a composite bogie frame. Furthermore, the structural integrity of the frame comprising the bolted joints was evaluated using finite element analysis according to the JIS E 4207 standard. The Tasi-Wu and Von-Mises failure criteria were used for determining the failure of the composite structure and bolted joints, respectively. A sub-modeling technique was introduced for investigating the performance of the bolted joints in greater detail. The analysis results demonstrated that the Tasi-Wu failure index of the composite structure near the bolted joints was reduced by approximately one-half after applying an insert without the screw thread. This implies that the structural durability of the bolted joints of a composite bogie frame could be improved by using a metal insert without the screw thread.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.823-826
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• 2001

A shape optimization of a rib of a bolster of a bogie frame is attempted and a dimension optimization on upper and lower plates is also carried out for the reduction of the weight of bogie frame. In addition, the dynamic characteristics of the weight reduced model are investigated by an analysis of a natural frequency and a transient analysis. The results show that the first natural frequency of an optimized model is larger than that of the lowest design value. And the results of transit analysis based on the experimental stress also show smaller value than the yield stress. Thus the optimized model attempted in this study is considered to be structurally stable and useful for the improvement of railway carriages.