http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
서정원,허현무,최재붕,김영진,Seo Jung-Won,Hur Hun-Mu,Choi Jae-Boong,Kim Young-Jin 대한기계학회 2005 大韓機械學會論文集A Vol.29 No.10
Damage often occurs on the surface of railway wheels due to wheel-rail contact fatigue. It should be removed before reaching wheel failure, because wheel failure can cause derailment with loss of life and property. The increase or decrease of the contact fatigue lift by the metal removal of the contact surface were investigated by many researchers, but they have not considered initial residual stress and traction force. The railway wheel has the initial residual stress formed during the manufacturing process, and the residual stress is changed by thermal stress induced by braking. The traction force and residual stress are operated on wheels of locomotive and electric motor vehicle. In this study, the effect of metal removal depth on the contact fatigue life for a railway wheel has been evaluated by applying lolling contact fatigue test. The effect of the traction force and metal removal on the contact fatigue life has been estimated by finite element analysis. It has been found that the initial residual stress determines the amount of metal removal depth if the traction coefficient is less than 0.15. If the traction coefficient is greater than 0.2, however, the amount of metal removal depth is independent on the intial residual stress.
서정원(Jung-Won Seo),나성훈(Sung-Hun Na),권성태(Sung-Tae Kwon),권석진(Seok-Jin Kwon) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
Railway wheels and axles belong to the most critical components in railway vehicles. The service conditions of railway vehicles became more severe in recent years due to the increase of speed. Therefore, a more precise evaluation of wheelset life and safety has been requested. The residual stress on wheel is formed during the manufacturing process which includes a heat treatment, and then is changed by contact stress developed by wheel/rail contact and thermal stress induced by braking. Since the wheel is designed to maintain a constant thickness up to a certain limit for the reprofilling process which requires contact surface removal, wheel surface thickness is reduced by surface removal and wear over the life of a wheel. The residual stress of contact surface is redistributed due to surface removal and thickness variation. The objective of this paper is to estimate the variation and magnitude of the residual stress of railway wheel according to surface removal.
공정시스템 , 이동현상 , 화학공정안전 : 원유증류공정의 최적 설계 - 2 . 최적 운전 조건의 결정 -
서정원(Jung Won Seo),김석준(Suk Joon Kim),김경현(Kyung Hyun Kim),오민(Min Oh),이태희(Tae Hee Lee) 한국화학공학회 2001 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.39 No.1
This paper considers the optimal operating conditions to minimize the annual capital and operating cost of a crude distillation unit, which consumes enormous energy. Reflecting on the complexity of intervention and interconnection among each unit, optimization task was carried out for the whole crude distillation unit including preheat train, atmospheric/vacuum distillation column, light naphtha stabilizer, etc. Optimization results were compared with those from commercial plant of which capacity is 150,000 BPSD. From this comparison, we can save 20,000,000 Kcal/h in the optimal case. It is also concluded that annual capital and operating cost was reduced from 10,649,000 US$/y to 9,185,230 US$/y, which is equivalent to 14% cost saving.
서정원(Seo Jung-Won),전현규(Jun Hyun-Kyu),김재철(Kim Jae-cheol),김대상(Kim Dae-sang) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.11월
Rolling contact fatigue damages on the surface of rail such as head check, squats are one of growing problems. Since rail fracture can cause derailment with loss of life and property, the understanding of rail fracture mechanisms is important for reducing damages on the surface of rail. In this study, the fatigue crack at the upper surface of rail was investigated by means of failure analysis. The investigation indicate that the crack grows at about 70° to the surface of the rail and this crack changed its growth direction ; either to branch downwards at about 20° or to branch upwards. Since the downward branches lead to fracture of the rail, they are more dangerous to the integrity of rails. It has been observed that White Etching Layer(WEL) occurs within the surface of broken rail. It was found that the fatigue crack initiation and propagation was accelerated by the WEL.
서정원(Jung-won Seo),구병춘(Byung-chun Goo),이동형(Dong-hyeong Lee),정흥채(Heung-che Jung) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.4
The problem of welding stresses and fatigue behavior is the main concerns of welding research<br/> fields. The residual stresses and distortion of structures by welding is exert negative effect on the<br/> safety of mechanical structures. That is, expansion of material by high temperature and distortion by<br/> cooling during welding process is caused of tensile and compressive residual stresses on welding<br/> material, and this residual stresses reduce fracture and fatigue strength of welding structures. The<br/> accurate prediction of residual stress and relaxation due to loading and post weld heat treatment of<br/> weld zone is very important to improve the quality of weldment. In this study, a finite element<br/> modeling technique is developed to simulate the relaxation of residual stresses due to loading and post<br/> weld heat treatment of weld zone. The accuracy of finite element models is evaluated based on<br/> experimental results and the results of the analytical solution.