Papers by Author: Tae Won Park

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Authors: Kyung Seok Sim, Tae Won Park, In Kyeong Hwang, Myeong Jun Kim, Hyun Moo Hur
Abstract: Two main factors for design of railway vehicles are stability and curving performance. Running performances, result from stiffness design of a primary suspension, between stability and curving are contrary to each other. The more longitudinal stiffness of a primary suspension stiff, the better straight performance is outstanding, however, curving performance is degenerated. Also, if the less longitudinal stiffness stiff, running performance has opposite characteristics. Curving performance of railway vehicles should be outstanding on small curved track which is in cities. If curving performance is improved, lateral contact force (i.e. flange contact force) of wheel and rail is decreased by improved spring so, wear and noise of wheels are decreased. Derailment risk from wheel and rail contact, of course, is decreased. Thus, it's important to design an axle spring of a primary suspension. The design of ensuring stability performance, of course, should be precede. An axle spring is designed using FEM tool which is ABAQUS also, rubber like material is modeled by Mooney-Rivlin model. Developed FE-axle spring model is analyzed and is produced also, this model is validated by test results of a load tester.
Authors: Il Ho Jung, Jong Hwi Seo, Hyung Suk Han, Tae Won Park, Joo Yong Kim
Authors: Myeong Jae Han, Tae Won Park, Ink Yeong Hwang, Jung Min Park
Abstract: The sense of stability during vehicle braking is largely related to brake performance. Among the brake parts, the brake pad must be working properly to ensure the braking performance and stability of the vehicle. That is, brake pads are required to maintain a uniform pressure distribution during braking. In addition, brake pads must maintain a proper braking force during rapid increases in temperature. In this study, the three-dimensional finite element (FE) model was developed to determine the distribution of the contact pressure of the brake pad. The temperature distribution on the pad surface was confirmed. The sensitivity to changes in material properties was verified using the developed model. Pad wear due to friction can be predicted by confirming the thickness variation due to heat. A fully coupled thermo-mechanical analysis of the developed FE model was performed using ABAQUS.
Authors: Myeong Jun Kim, Tae Won Park, Chul Hyung Lee, Inchul Seong
Abstract: In this study, the tube material for Self-Inflating Tire was synthesized. A few suitable materials for the tube material compounding process were identified through a literature review. Using the material properties of this tube, CAE modeling was done for analysis. The ANSYS Fluid Structure Interaction (FSI) method was then used to consider the internal flow with the structure. In addition, a machine was prepared for testing the performance of the tube. The results of the CAE analysis were compared with results of the testing machine. The developed equipment and systems can be used for the manufacture of high-performance and safe tires. Finally, the prototype of the tube was prepared and fitted in a tire, and the driving performance of the vehicle tested. Using this test result, compatibility of the tube's material has been confirmed.
Authors: Ji Won Yoon, Kab Jin Jun, Tae Won Park
Abstract: Recently, the finite element absolute nodal coordinate formulation(ANCF) was developed for large deformation analysis of flexible bodies in multi-body dynamics. This formulation is based on finite element procedures and the general continuum mechanics theory to represent elastic forces. In this paper, a computational method, which predicts the dynamic and structural properties of a very flexible beam in a multibody system, is presented based on Euler-Bernoulli beam theory and ANCF. In order to consider the dynamic interaction between a continuous large deformable beam and a rigid multibody system, a combined system equations of motion was derived by adopting absolute nodal coordinates and rigid body coordinates. The efficiency and reliability of the computational results are verified by comparison with a commercial program. These methods can be applied for predicting the dynamic stress and fatigue life of the wire harness used in a robot system. The process of predicting the fatigue life using the proposed method in this paper may be applied to continuous mechanical parts of various dynamic systems.
Authors: Kab Jin Jun, Ji Won Yoon, Tae Won Park, Joong Kyung Park
Abstract: An Over Head Transportation (OHT) vehicle is used to transport large loads in a factory more efficiently. To maximize productivity, the speed and load requirement for the OHT vehicle is continually increasing. This may create a repetitive dynamic load and thus cause fatigue failure in related components. In this paper, a computer aided engineering (CAE) method is proposed for fatigue life prediction in the early design stage using multibody dynamic analysis and the linear damage rule. The process of predicting the fatigue life using the proposed computer models in this paper may be applied to structures of various mechanical systems.
Authors: Young Guk Kim, Seog Won Kim, Chan Kyoung Park, Kyoung Ho Moon, Tae Won Park
Abstract: Evaluation of the ride comfort for railway vehicles can be divided into two classes; the long-term evaluation of ride comfort and the momentary evaluation of ride comfort. In the present paper, the ride comfort of railway vehicles are investigated for high speed trains in Korea. The long-term ride comfort has been analyzed by a statistical method and the momentary ride comfort has been analyzed by using the longitudinal acceleration, the jerk and the stationary lateral acceleration.
Authors: Nam Po Kim, Jung Seok Kim, Sung Il Seo, Tae Won Park
Abstract: This paper shows the experimental study to evaluate the fatigue strength of a bogie frame for Korean tilting train. The various load cases were established based on the international standard (UIC615-4) and the special tilting load case, which is unique in the tilting train, was derived by dynamic analysis and logical assumption of operation under worst tilting condition. The experimental study was conducted by means of two ways, both static and fatigue loading test. Through the static load test, the safety against fatigue was assessed using Goodman diagram of the material used. The fatigue load test was carried out up to 1x107cycles. The fatigue strength was assessed by fatigue crack inspection by means of NDT test at the stage of 6x106cycles and 1x107cycles.
Authors: Sung Pil Jung, Hyun Seok Song, Tae Won Park, Won Sun Chung
Abstract: Thermal energy generated by the friction between the disc and pad is transferred to both components and causes thermal expansion of material of each component, and futher affects the friction contact condition. This is the main factor of the thermoelastic instability (TEI) of a disc brake. In this study, TEI is analyzed using the finite element analysis technique. Three dimensional thermo-mechanical analysis model of the disc brake system is created. An intermediate processor based on the staggered approach is used to exchange analysis results: temperature, friction contact power, nodal displacement and deformation. Disc thickness variation (DTV) and temperature distribution of the disc are calculated, and the tendency and meaning of the results are discussed.
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