• 대한기계학회논문집A
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• 제27권9호
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• pp.1597-1606
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• 2003

Static analysis using hybrid finite element(FE) method has been applied to characterize the influence of position, runout and thickness errors of the sun, ring and planet on the bearing forces and critical tooth stress. Some guidelines for tolerance control to manage critical stress and bearing forces are deduced from the results. Carrier indexing error planet assembly and planet tooth thickness error are most critical to reduce planet bearing force and maximize load sharing as well as to reduce critical stresses. Sun and carrier bearing forces due to errors increase several times more than those of normal condition.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.157-162
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• 2005

Parallel implementation and performance assessment of the grid assembly in a structured chimera grid approach is studied. The grid assembly process, involving hole cutting and searching donor, is parallelized on the PC cluster. A message passing programming model based on the MPI library is implemented using the single program multiple data(SPMD) paradigm. The coarse-grained communication is optimized with the minimized memory allocation because that the parallel grid assembly can access the decomposed geometry data in other processors by only message passing in the distributed memory system such as a PC cluster. The grid assembly workload is based on the static load balancing tied to flow solver. A goal of this work is a development of parallelized grid assembly that is suited for handling multiple moving body problems with large grid size.

• 한국자동차공학회논문집
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• 제19권2호
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• pp.111-116
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• 2011

Three-dimensional finite element analyses have been performed to improve the durability of bulkhead. To keep pace with design changes and concentrate on regions of interest, SUBMODEL technique in ABAQUS was used for analysis. An analysis was conducted with following load cases: 1) Cap press-fit, 2) Bearing crush, 3) Bolt assembly, 4) Hot assembly, 5) Firing load, 6) Alternating firing load, 7) 2nd hot assembly. Fatigue analysis was done using commercial software FEMFAT and fatigue factors at the interested regions such as bolt tip area, counter bore, breathing hole, honing clearance were calculated and compared to aid design validation. Finite element modeling in the area of thread engagement used a simple constraint equations. Increasing bolt length, to a minimum of 39 mm above joint face gives a better fatigue resistance to the bulkhead. Breathing hole helps not only circulate the air in the crankcase but also fatigue resistance of bulkhead by relieving the stress at the critical locations.

• 대한조선학회논문집
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• 제36권3호
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• pp.122-133
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• 1999

완성되어진 블록을 이용한 탑재의 과정에서 발생하는 블록 경계간의 판재 겹쳐짐 현상, 과도한 간격 및 단차의 발생현상은 선박의 건조비용과 공수를 증가시키는 요인이 된다. 본 논문에서는 블록의 조립 및 탑재에 관한 시뮬레이션 시스템을 제안하고 이중 조립에 관한 시뮬레이션을 용접순서에 따라 용접변형 및 자중을 고려하여 유한요소해석을 ANSYS를 이용하여 수행하였다. 용접에 의한 변형은 실험에 의한 변형량을 이용한 등가강성에 따른 등가 하중을 사용하여 탄성적인 해석법을 수행하여 예측하였으며 선체 이중저 평블록을 패널 조립법에 근거한 조립순서에 따라 시뮬레이션을 수행하였다. 시뮬레이션을 통한 변형으로부터 조립순서에 따른 중간 제품의 형상의 변화에 의한 강성의 변화에 기인한 변형량의 차이를 확인 할 수 있었으며, 자중의 효과를 반드시 고려하여야 함을 확인 할 수 있었다.

• Nuclear Engineering and Technology
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• 제33권3호
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• pp.298-306
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• 2001

As fuel burnup proceeds, thermal gradients, differential swelling, and inter-assembly loading may induce assembly duct bowing. Since duct bowing affects the reactivity, such as long or short term power-reactivity-decrement variations, handling problem, caused by top end deflection of the bowed assembly duct, and the integrity of the assembly duct itself. Assembly duct bowing were first observed at EBR-ll in 1965, and then several designs of assembly ducts and core restraint system were used to accommodate this problem. In this study, NUBOW-2D KMOD was used to analyze the bowing behavior of the assembly duct under the KALIMER(Korea Advanced Liquid MEtal Reactor) core restraint system conditions. The mechanical behavior of assembly ducts related to several design parameters are evaluated. ACLP(Above Core Load Pad) positions, the gap distance between the ducts, and the gap distance between the duct and restraint ring were selected as the sensitivity parameter for the evaluation of duct deflection.

• 대한기계학회논문집A
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• 제32권5호
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• pp.402-410
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• 2008

The heavy duty diesel engine must have a large output for maintaining excellent mobility. In this study, a three dimensional finite element model of a heavy-duty diesel engine was developed to conduct the stress analysis. The FE model of the heavy duty diesel engine main parts consisting with four half cylinder was selected. The heavy duty diesel engine parts includes with cylinder block, cylinder head, gasket, liner, bearing cap, bearing and bolts. The loading conditions of engine were pre-fit load, assembly load, and gas load. As the results of structural analysis, because the stress values of cylinder block and bearing cap did not exceed the basic design can be satisfied. But on the part which contacts with cylinder block and bearing cap the stress value exceeds the allowable strength of material. In order to decrease the stress at that part, it was optimized with parametric study.

• 대한안전경영과학회지
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• 제19권1호
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• pp.203-210
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• 2017

Companies are pursuing the management of small quantity batch production or JIT(Just-in-time) system for improving the delivery response and LOB(Line Balancing) in order to satisfy consumers' increasing demands in the current global economic recession. And in order to improve the growth of production for reducing manufacturing cost, improvements of the Load Balancing have become an important reformation factor. Thus this paper is aimed at warehouse which procures materials on the assembly line in procurement logistics of automotive logistics and proceed with research on heuristic algorithm development which can increase the Load Balancing of workers. As a result of this study, when applied the primary target value, it was verified that the whole workers decreased from 28 to 24. Furthermore, when specified the secondary target value and applied algorithm once more, it was verified that the Load Balance Ratio was improved from 44.96% to 91.7%.

• 한국기계가공학회지
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• 제17권1호
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• pp.23-33
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• 2018

In the general manual feeder of an LED lighting assembly system, many workers are needed to supply parts to the main conveyor. The automatic feeder for modern automation lighting assembly systems consists of a completely automated feeding system and a magazine system that supplies the parts automatically. A standardized LED panel and diffusion cover is stacked in the cartridge of the magazine system. The structural safety of the automatic feeding system with regard to handling the load from the panels and covers stored in the cartridge should be guaranteed. LED convergency lighting modules are assembled using two LED panels and one diffusion cover in an automatic feeder. In this study, the structural safety and fatigue life of the automatic feeder and magazine were analyzed by considering the load generated in the automatically assembled LED convergency lighting system. In addition, the dynamic behavior of each auto-feeding system and magazine delivery system was visualized, and the working process was evaluated via dynamic simulation using a virtual engineering method. A tack time table for automatic feeding systems was derived by developing a virtual prototype.

• 한국안전학회지
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• 제25권6호
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• pp.146-154
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• 2010

In this study the experimental results of fatigue specimen for the Strand Stay Cable Assembly of Extadosed bridges is investigated. The fatigue test and tensile experiment is conducted to 6 kinds of specimens. Test specimen OVM250-31 Strand Cable System manufactured by china OVM B-Machinery Co., Ltd, and OVM250-42 Parallel Strand Stay Cable Assembly manufactured by china OVM B-Machinery Co., Ltd, are passed for fatigue test and rupture tensile test. But Test specimen OVM250-42 Parallel Strand Stay Cable Assembly manufactured by korean A-Machinery Co., Ltd, is not passed for fatigue test conducted according to the "Recommendation for Stay Cable Design. The test result are compared to the fatigue criteria of PHI 2001 for cyclic load, and it is concluded that the current korean design code will be needed for representing the fatigue load in Hot Dip Galvanized Strand Stay Cable. It is verified that the new korean specification and quality criteria of Strand Stay Cable and exact experimental applied process will be needed.

• Nuclear Engineering and Technology
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• 제46권4호
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• pp.529-540
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• 2014

In this research, a drop impact analysis of a fuel assembly in a research reactor is carried out to determine whether the fuel plate integrity is maintained in a drop accident. A fuel assembly drop accident is classified based on where the accident occurs, i.e., inside or outside the reactor, since each occasion results in a different impact load on the fuel assembly. An analysis procedure suitable for each drop situation is systematically established. For an accident occurring outside the reactor, the direct impact of a fuel assembly on the pool bottom is analyzed using implicit and explicit approaches. The effects of the key parameters, such as the impact velocity and structural damping ratios, are also studied. For an accident occurring inside the reactor, the falling fuel assembly may first hit the fixing bar at the upper part of the standing fuel assembly. To confirm the fuel plate integrity, a fracture of the fixing bar should be investigated, since the fixing bar plays a role in protecting the fuel plate from the external impact force. Through such an analysis, the suitability of an impact analysis procedure associated with the drop situation in the research reactor is shown.