• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.351-357
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• 2007

The transition zone between railway embankment and structures, or different track types is known to be an area in which problems often arise and where extra care needs to be taken with maintenance. Differences in track stiffness have dynamic effects and these increase the force in the track and the extent of deformation. In this study, the criteria for the change ratio of track stiffness along transition area, and proper transition length are presented through train/track interaction analyses. Those are derived on the basis of permissible limitations of train and track performances such as rail stress, uplift force of fastener, reduction of dynamic wheel force, and acceleration of car body. A feasible method of evaluation of track stiffness which is necessary when a designer reviews whether the criteria are satisfied or not is also presented.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.404-411
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• 2007

Reinforced roadbeds are valued from the point of view of maintenance as well as enhanced mechanical capacity. They support more train load and less transmit to the sub-layers than general roadbeds. Also, the lateral sloping surface of the reinforced roadbed and its low permeability, achieved by the controlled compaction, increase drainage capability and prevent the softening of sub-layers. In the study, a series of cross-hole tests was performed to observe the temporal changes in the stiffness of reinforced roadbeds, if any, due to the cyclic loading of trains and alternating rainy and frozen seasons at Pyeong-taek experimental site. The three types of reinforced roadbed materials are slag, crushed stones, and soils, and the thickness of all the reinforced roadbeds is 0.8m. The stiffness of the slag and soil reinforced roadbeds was not changed or slightly decreased. The stiffness of the crushed stone was somewhat increased and is inferred to being densified close to surface.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.680-683
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• 2010

The lateral stiffness of the track structure is very important mechanical property to prevent the track buckling and progress of misalignment. The increasing methods of the lateral stiffness of the track structure are the following; increases of the lateral ballast resistance, and increases of the lateral stiffness of the track panel. In order to increase the lateral stiffness of the tack panel, some of the sleepers resist together against the lateral movement can be the most economical and mechanical method. In this paper, H-typed sleeper developed to solve this problem is introduced and the mechanical advantages of this sleeper are investigated.

• 펄프종이기술
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• 제36권2호
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• pp.17-23
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• 2004

The effects of refining consistency and plate gap on the specific energy consumption and physical properties of liner were investigated. Higher refining consistency and narrower plate gap brought about the reduction of specific energy consumption to decrease the freeness. Refining consistency and plate gap did not affect the bulk, Taber stiffness and compression index. The reduction of freeness and/or the increase of specific energy consumption caused the decrease of bulk and Taber stiffness, but increased the compression index. The effect of grammage on bulk was not observed, but Taber stiffness and compression index were increased with grammage. The bulk was decreased with the reduction of freeness rapidly at the above 400 mL CSF, and then levelled off. It is expected that the reduction of energy consumption could be obtained from the application of higher refining consistency and narrower plate gap during refining.

• 한국공작기계학회논문집
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• 제17권3호
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• pp.59-64
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• 2008

Spindle units of machine tool are very important part in the manufacturing area. Recently high speed machining has become the main issue of metal cutting. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Due to increase of the rotational speed of the spindle, there has been renewal of interest in tooling system of high speed spindle. This paper concerns the static stiffness in the main spindle interface according to variation of clamping force, rotational speed and tool holder shank. Finite element analysis is performed by using a commercial code ANSYS workbench. From the results, it has been shown that the geometry of tool holder shank is mostly influence on the variation of the static stiffness in the main spindle interface.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1628-1636
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• 2008

Construction of concrete slab track is trending to increase gradually in national and international for reduction in track maintenance cost and secure of ride comfort. But elastic pad becomes superannuated due to repeated train operation. After all, it brings change of pad stiffness and it could directly act on track and bridge as load transmission and impact force. In this study, we carried out laboratory test changing pad stiffness after making a model of 15m bridge and laying concrete slab track. Also, we carried out static and dynamic behaviors test(stress, natural frequency, damping ratio, vibrational acceleration, deflection) of bridge and track and experimentally analyzed them by change of elastic pad stiffness on rail fastener.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.14-15
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• 2019

The demand for drywall is increasing as the structural type of apartment building is changing to a rigid frame structure. At present, the thickness of the gypsum board used for drywall is mostly 9.5mm and is required to be changed to 12.5mm to improve the performance of the wall. A structural safety test has been conducted in accordance with KS F 2613 to verify the effect of changing the thickness of the gypsum board to 12.5mm in terms of improvement as to stiffness. As a result of the test, the stiffness of the drywall has increased by about 19.6% and the impact resistance by about 30.4%.

• 한국자동차공학회논문집
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• 제11권4호
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• pp.226-231
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• 2003

There have been many attempts to make kart chassis domestically to lower the price of complete kart. However nobody made a successful chassis due to the lack of understanding the characteristics of kart chassis frame. In this work, a baseline chassis frame under the bending and torsional load is studied. Design target is that the baseline chassis frame is quite adequate not only for the beginners but also for the beginning racers. Results from the analysis are used as a guide to design or modify the baseline chassis with the goal of proper torsional stiffness. Minimum increase in weight is being forced. As a result, the baseline chassis frame was designed, made, and tested. Based on the design results, complete karts are being manufactured by the small 1 size domestic company and these karts are being sold and run in the market.

• 한국정밀공학회지
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• 제18권12호
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• pp.145-151
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• 2001

The dimensional accuracy of the cold forged part is depended on the elastic characteristics of the die. To increase the stiffness of the prestressed die, the first stress ring of the tungsten carbide alloy (WC) is considered. For the design, Lame's equation is used. Diameter ratios and interferences have been determinated by maximum inner pressure without yielding of materials. The design of the prestressed die has been compared with the conventional one. For the comparison, the FE-analysis using ANSYS has been performed. The results indicate that the prestressed die with the high stiffness can be obtained by the using the high stiffness material as the first stress ring.

• 한국시뮬레이션학회논문지
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• 제8권3호
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• pp.39-48
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• 1999

A finite element model of geared rotor system with flexible bearings were used to simulate the critical speeds and to investigate the effects of bearing coefficients on the dynamic behaviors of the systems. The finite element model includes the effects of tooth mesh stiffness, gyroscopic moment, rotary inertia, shear, and torque of the shaft. The gear mesh was modelled as a pair of rigid disks connected by a spring of time varying stiffness. The time varying mesh stiffness results in the abrupt change of the critical speeds of spur geared systems. As the bearing stiffness increases, critical speeds increase rapidly in case of stiff shafts, compared with flexible shafts.