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구정서(Jeongseo Koo),조현직(Hyunjik Cho) 한국자동차공학회 2004 한국 자동차공학회논문집 Vol.12 No.3
In this paper, the structural strength of a rolling stock seat were numerically evaluated under several design load conditions based on the UIC requirements. The rolling stock seat was designed for the high speed train of a Chinese conventional line. To maximize its weight reduction and structural strength, an aluminium alloy, ALDC8-T5, was applied to the base frame, side frames and armrests. The designed seat frame satisfied the strength requirements on inertia loads and fatigue test conditions. However, it couldn't satisfy the requirements on the static test conditions of UIC 566 OR. Therefore, some design modifications were suggested and numerically evaluated whether the static test requirements could be satisfied or not.
Cut-out이 있는 Box형 차체의 하부구조 소재대체 경량화 설계 방법
조정길(Jeonggil Cho),구정서(Jeongseo Koo),정현승(Hyunseung Jung) 한국자동차공학회 2013 한국 자동차공학회논문집 Vol.21 No.2
In this paper, a theoretical weight-reduction method was suggested to substitute an underframe material of a box-type bodyshell having cut-outs with an alternative light-weight material. To utilize the material substitution method previously developed for a box-type hybrid bodyshell not having cut-outs, we derived a box-type baseline model without cut-outs which is similar to the stiffness condition of a box-type bodyshell having cut-outs. To do this, the thicknesses of roof and walls of the baseline model were determined such that the deflection of the baseline model under a distributed vertical load condition is equal to the sum of the theoretical section deflections of the original box model with cut-outs. Next, to derive a hybrid bodyshell by under-frame material substitution, the material substitution method for a box-type hybrid bodyshell without cut-outs was applied to the box-type baseline model. Finally, we compared the FE simulation results of the derived hybrid bodyshells having cut-outs for various materials with the theoretical results of the suggested method, and we obtained their good correlations.
급구배 산악열차의 차체 구조 및 피로 안전성에 대한 연구
박정필(Jeongpil Park),구정서(Jeongseo Koo),김준우(Junwoo Kim),정의철(Euicheol Jeong) 한국철도학회 2015 한국철도학회 학술발표대회논문집 Vol.2015 No.10
국내 국토의 75%정도가 산악지형으로 구성되어 있고, 국내에 산악열차의 제작 및 운영에 대한 사례가 전무하여 산악열차와 같은 교통 인프라 구축 하는데 어려움이 있다. 본 연구에서는 산악열차의 차체를 국외 철도차량의 규정인 EN12663의 구조 및 피로 평가기준으로 구조 및 피로 수치해석을 수행 하였다. 수치해석 결과를 토대로 구조 및 피로 안전성 평가결과 안전율이 높아서 차체가 과설계 된 것으로 판단하여 치수 최적화 설계를 수행하였다. 그 결과, 치수 최적화 설계로 약 14%정도의 차체경량화 되었고, EN12663에서 제시한 구조 및 피로 강도 평가 기준도 만족하여서 차체의 구조 및 피로의 안전성을 검증하였다. Seventy-five percent of internal territory consists of mountainous area and it is difficult to construct transportation infrastructure for the gradient mountain railway because of there are no experiences of manufacturing and operating mountain railway. The study performed and evaluated numerical analysis about the frame of mountain railway carbody by applying the international standard EN12663 on structural strength and fatigue of rolling stock. The first design of the carbody is considered to be overdesigned because safety factor is high in the evaluation of structural strength and fatigue based on the numerical analysis results. Thus, the size optimization design was carried out. As the results, the weight of the carbody was reduced to about 14% through the optimization, and the results met structural strength and fatigue evaluation criterions. Accordingly, the structural strength and fatigue integrity of carbody were verified.
오현석(Hyunsuk Oh),구정서(Jeongseo Koo) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
In this thesis, new theoretical derailment coefficient model with using wheelset model is suggested. Traditional derailment coefficient from Nadal"s formulus, which has been using in domestic derailment rule, has difficulty in figuring out derailment coefficient under various conditions on wheel dimensions and applied forces. Therefore, the new theoretical derailment coefficient model was suggested to establish fundamental basis to determine the realistic derailment coefficient. The new theoretical derailment coefficient is mainly composed of various mechanical factors like the lateral force, the unloadings of left and right vertical forces, the friction coefficient, the wheel diameter, the wheel gauge, the distance between the suspension support and the wheel center point, a flange angle and so on. The validity of the theoretical derailment coefficient was confirmed with the dynamics simulations under the changes of the mechanical factors.
PRT차량의 Rolling 감소를 위한 Anti-roll bar의 적용 연구
김현태(Hyuntae Kim),구정서(Jeongseo Koo),김준우(Junwoo Kim),조정길(Jeonggil Cho),정락교(Raggyo Jeong),강석원(Seokwon Kang) 한국철도학회 2014 한국철도학회 학술발표대회논문집 Vol.2014 No.10
본 논문에서는 PRT 차량의 Rolling 감소를 위해 Anti-roll bar 를 적용하여 동특성 분석을 진행 하였다. 다물체 동역학 프로그램인 Adams/car 를 이용하여 Anti-roll bar 를 모델링하여 ISO 3888 (Double Lane Change test)를 진행하였다. 그 결과, 앞뒤 현가장치 모두 Anti-roll bar 를 장착한 경우 가장 큰 감소율을 보였다. Anti-roll bar 를 장착하지 않은 경우 대비 Roll displacement 의 경우 30.4% 감소 Roll rate 의 경우 29.5% 감소를 보였다. 차량의 주행안정성에 영향을 미치는 Side slip angle 의 경우도 12.5% 감소 하였다. 그러나 Antiroll bar 를 장착한 경우에 횡가속도 와 Yaw 가 증가 하였으나 그 차이는 거의 없다. In this paper, we performed the dynamic analyses of a PRT vehicle model with anti-roll bars to decrease rolling motions. The PRT vehicle with anti-roll bars was simulated according to the ISO 3888, Double Lane Change test, by using the multi-body dynamics software. As the result, the roll angle of the PRT vehicle with anti-roll bars on the front and rear suspension was the smallest when compared with the cases with one anti-roll bar or without any anti-roll bar. A roll displacement and rolling rate could be reduced by 30.4% and 29.5% respectively. The side slip angle, which affects vehicle running stability, was reduced by 12.5%. Although the lateral acceleration and the yawing angle were increased, the increases of these values were small and negligible.