• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.143-150
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• 2002

The characteristics of rubber cup seal is highly nonlinear due to the nature of the material's non-linearity and large deformation with frictional contact. And the performance of sealing in master cylinders of automobile is one of the most important factors which affects the safety of drivers. The effects of various shape of the primary cup seal in clutch master cylinder was investigated to reduce oil leakage and to obtain a long reliable life. Deformation and distribution of stresses on the primary cup seal against hydraulic oil pressure were analyzed with changing design parameters such as depth and radius in cup-seal. The obtained results indicate that the depth of cup seal plays a major role on deformation resulting in the sealing force to the wall of clutch master cylinder.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.350-354
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• 1995

This paper is about impact behavior of cylinder container, made of steel fiber reinforced polymer-impregnated concrete(SFPIC), for intermediate and low level radwaste disposal. In order to obtain the material properties of the SFPIC, steel ball impact tests were done to SFPIC beams and its simulation by finite element method was performed. By using the material properties in finite element impact analysis of the SFPIC concrete cylinder, we obtained impact behavior of the cylinder.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.6
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• pp.133-139
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• 2011

Maintaining adequate sealing in engine cylinder head is a crucial factor in engine design. Failure of engine operations occurs mainly owing to the leaking by decreased sealing pressure. Reliability-robustness concept is applied to the engine cylinder head system. Deterministic way to obtain engineering solution in CAE industry may not consider the effects of noises and disturbances experienced during operation. However, analytical reliability-robustness concept may make possible to reduce the sensitivity of system with noise factors. Influences of design factors including noise factors would be predicted in analytical way. Optimized design may be obtained by shrinking variability and shifting to design target. Three-dimensional finite element analyses have been performed to apply analytical reliability-robustness concept.

• Transactions of Materials Processing
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• v.19 no.6
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• pp.372-377
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• 2010

Elasto-plastic finite element analysis was performed for a burnishing process for the inner surface of a cylinder by mandrel. Three different configurations in roughness of the inner surface, two different thicknesses of the cylinder wall, and five different diameters of the mandrel were selected for the present investigation. Although the surface roughness was improved with the increase of the mandrel diameter, defects of folding occurred as the mandrel diameter exceeded certain limits. Improvements in the surface roughness, distributions of effective strain, effective stress and residual circumferential stress, and the variation of mandrel force were also investigated.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.9 s.252
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• pp.1049-1061
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• 2006

In the study, the flow stress of material and friction condition were determined by using the cylinder compression test and numerical method. We proposed the flow stress equation including the initial yield strength to predict it from the upper bound method. The upper bound technique uses the velocity field which includes two unknowns to effectively express bulging. Also, inverse engineering technique uses the object function to minimize area enclosed by load-stroke curve. The friction factor is determined from the radius of curvature of the barrel by cylinder compression test. Flow stress and initial yield strength predicted from the above techniques are verified through the finite element simulation.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.8 no.2
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• pp.73-80
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• 1979

This study describes the conduction of heat in the discharge head of air compressor. It also gives a base for a finite elements analysis of two dimenional steady -state heat conduction in the cylinder head of air cooled type reciprocating compressor. Using a single cylinder compressor operated at a given speed, tests were made observing outside temperature, final pressure and discharge temperature of air in cylinder head. As a result, the following were obtained : (1) The rate oi heat flow from the inner surface of discharge head to outside wall reach 46. 328 kcal /h at a speed of 796rpm under the constant temperature of inlet air. (2) The compression work of air increase in accordance with temperature rise of inlet air.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.2
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• pp.144-153
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• 2016

This paper aims to demonstrate the design, structure analysis, and hydrostatic pressure test of the cylinder used in 2000m water depth. The cylinder was designed in accordance with ASME pressure vessel design rule. The 1.5 times safety factor required by the general rule was applied to the design of the cylinder, because ASME rule is so excessive that it is not proper to apply to the hydrostatic pressure test. The finite element analysis was conducted for the cylinder. The cylinder was produced according to the design. The hydrostatic pressure test was conducted at the hyperbaric chamber in KRISO. The results of finite element analysis(FEM) and those of the hydrostatic pressure test were almost the same, which showed that the design was exact and reliable.

• International Journal of Automotive Technology
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• v.7 no.1
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• pp.109-114
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• 2006

Half-beads of multi-layer-steel cylinder head gaskets take charge of sealing of lubrication oil and coolant between the cylinder head and the block. Since the head lifts off periodically due to the combustion gas pressure, both the dynamic sealing performance and the fatigue durability are essential for the gasket. A finite element model of the halfbead has been developed and verified with experimental data. The half-bead forming process was included in the model to consider the residual stress effects. The model is employed to assess the dependence of the sealing performance and the fatigue durability on the design parameters of half-bead such as the width and height of bead and the flat region length. The assessment results show that the sealing performance can be enhanced without significant deterioration of the fatigue durability in a certain range of the half-bead width. In the other cases the improvement of sealing performance is accompanied by the loss of the fatigue durability. Among three parameters, the bead width has the strongest influence.

• Journal of Ocean Engineering and Technology
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• v.17 no.5 s.54
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• pp.66-75
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• 2003

Long cylinder, subjected to internal pressure, is important in the analysis and design of nuclear fuel rod structures. In many cases, long cylinder problems have been considered as a plane strain condition. However, strictly speaking, long cylinder problems are not plane strain problems, but rather a general plane strain (GPS) condition, which is a combination of a plane strain state and a uniform strain state. The magnitude of the uniform axial strain is required, in order to make the summation of the axial force zero. Although there has been the GPS element, this paper proposes a general technique to solve long cylinder problems, using several pseudo-general plane strain (PGPS) elements. The conventional GPS elements and PGPS elements employed are as follows: axisymmetric GPS element (GA3), axisymmetric PGPS element (PGA8/6), 2-D GPS element (GIO), 3-D PGPS element (PG20/16), and reduced PGPS elements (RPGA6, RPG20/16). In particular, PGPS elements (PGA8/6, PG20/16) can be applied in periodic structure problems. These finite elements are tested, using several kinds of examples, thereby confirming the validity of the proposed finite element models.

• Wind and Structures
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• v.30 no.5
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• pp.533-546
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• 2020

Large Eddy Simulation (LES) is used to study the effects of steady slot suction on the aerodynamic forces of and flow around a wall-mounted finite-length square cylinder. The aspect ratio H/d of the tested cylinder is 5, where H and d are the cylinder height and width, respectively. The Reynolds number based on free-stream oncoming flow velocity U_∞ and d is 2.78×10⁴. The suction slot locates near the leading edge of the free end, with a width of 0.025d and a length of 0.9d. The suction coefficient Q (= U_s/U_∞) is varied as Q = 0, 1 and 3, where U_s is the velocity at the entrance of the suction slot. It is found that the free-end steady slot suction can effectively suppress the aerodynamic forces of the model. The maximum reduction of aerodynamic forces occurs at Q = 1, with the time-mean drag, fluctuating drag, and fluctuating lift reduced by 3.75%, 19.08%, 40.91%, respectively. For Q = 3, all aerodynamic forces are still smaller than those for Q = 0 (uncontrolled case), but obviously higher than those for Q = 1. The involved control mechanism is successfully revealed, based on the comparison of the flow around cylinder free end and the near wake for the three tested Q values.