• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 유기절연재료 방전 플라즈마연구회
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• pp.104-107
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• 2003

The ageing cause in many porcelain suspension insulators which occur on transmission and distribution line with dead-end stings is mechanical stress in interface between porcelain and cement materials. It is known that the principal mechanical stress which give electrical failure is the results of the displacement is due to cement growth. We studied an analysing method to find out a deformation of brittle porcelain with a thermal expansion of cement for suspension insulator. These simulation analysis and experimental results show that cement volume growths affect severely to be mechanical failure ageing. These simulation analysis and experimental results show that axial loading affects of Porcelain insulators severely to be mechanical failure ageing.

• Structural Engineering and Mechanics
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• 제19권1호
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• pp.73-96
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• 2005

For the spatially coupled free vibration analysis of shear deformable thin-walled non-symmetric curved beam subjected to initial axial force, an exact dynamic element stiffness matrix of curved beam is evaluated. Firstly equations of motion and force-deformation relations are rigorously derived from the total potential energy for a curved beam element. Next a system of linear algebraic equations are constructed by introducing 14 displacement parameters and transforming the second order simultaneous differential equations into the first order simultaneous differential equations. And then explicit expressions for displacement parameters are numerically evaluated via eigensolutions and the exact $14{\times}14$ dynamic element stiffness matrix is determined using force-deformation relations. To demonstrate the accuracy and the reliability of this study, the spatially coupled natural frequencies of shear deformable thin-walled non-symmetric curved beams subjected to initial axial forces are evaluated and compared with analytical and FE solutions using isoparametric and Hermitian curved beam elements and results by ABAQUS's shell elements.

• 한국기계가공학회지
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• 제17권3호
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• pp.34-38
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• 2018

Recently, the turbo charger has become an important part because it yields little displacement and high power while downsizing the engine's fuel ratio for environmental purposes. In this study, flow analysis was conducted to form the basis of data regarding the best efficiency. The axial displacement was changed from none to 25 mm by controlling the configuration of the turbo charger and the flow analyses were compared with each other. The maximum rate of the outlet of model 1 was 46.36 m/s and the maximum pressure of model 4 was 0.761946 Pa. The maximum flow rate of model 4 was 0.000187650 kg/s. This study's result should aid in the effective design of a turbo charger with high performance.

• Architectural research
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• 제15권1호
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• pp.43-52
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• 2013

The reinforced concrete shear walls are being widely used in the domestic high-rise residential complex buildings. If designed by current codes, the special boundary element is needed in almost all high-rise shear wall buildings. This is because the equation for determining the provision of the special boundary element in the current codes cannot reflect the characteristics of the domestic high-rise shear walls with high axial load ratio and high proportion of elastic displacement to total displacement. In this study, a new equation to be able to reflect the characteristics is proposed. By using the equation, the special boundary element may not be necessary in certain cases so that structural engineers can relieve the burden of installing the special boundary element in every high-rise shear wall.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.906-915
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• 2004

Derivation procedures of exact dynamic stiffness matrices of thin-walled curved beams subjected to axial forces are rigorously presented for the spatial free vibration analysis. An exact dynamic stiffness matrix is established from governing equations for a uniform curved beam element with nonsymmetric thin-walled cross section. Firstly this numerical technique is accomplished via a generalized linear eigenvalue problem by introducing 14 displacement parameters and a system of linear algebraic equations with complex matrices. Thus, displacement functions of dispalcement parameters are exactly derived and finally exact stiffness matrices are determined using clement force-displacement relationships. The natural frequencies of the nonsymmetric thin-walled curved beam are evaluated and compared with analytical solutions or results by ABAQUS's shell elements in order to demonstrate the validity of this study.

• Structural Engineering and Mechanics
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• 제13권3호
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• pp.241-260
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• 2002

The effect of shear coupled with axial force variation on the inelastic seismic behaviour of reinforced concrete bridge piers is investigated in this paper. For this purpose, a hysteretic axial-shear interaction model was developed and implemented in a nonlinear finite element analysis program. Thus, flexure-shear-axial interaction is simulated under variable amplitude reversed actions. Comparative studies for shear-dominated reinforced concrete columns indicated that a conventional FE model based on flexure-axial interaction only gave wholly inadequate results and was therefore incapable of predicting the behaviour of such members. Analysis of a reinforced concrete bridge damaged during the Northridge (California 1994) earthquake demonstrated the importance of shear modelling. The contribution of shear deformation to total displacement was considerable, leading to increased ductility demand. Moreover, the effect of shear with axial force variation can significantly affect strength, stiffness and energy dissipation capacity of reinforced concrete members. It is concluded that flexure-shear-axial interaction should be taken into account in assessing the behaviour of reinforced concrete bridge columns, especially in the presence of high vertical ground motion.

• Journal of Biosystems Engineering
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• 제16권1호
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• pp.27-36
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• 1991

This study was carried out getting basic data for developing a new combine which is suitable for the cultivating situation in Korea or Southeast Asia. The relation of the amount of unthreshed grains and the axial displacement of crop in threshing process was attempted to formulate mathematically in a threshing chamber of axial-flow threshing unit. It was found that unthreshed grain is an exponetially-decaying functon of axial displacement of grains based on available data. Threshing experiments were performed to validate the mathematical model by changing various levels of pertinent variables for malting barley. Good correlation were obtained between the theoretical calculation and observed data for various test conditions, such as inclination, vane pitch, concave length, drum speed, feeding velocity, stream weight, moisture content. Therefore the model can be used for general purpose to find the amount of unthreshed grain if the mean rate of occurence of threshing of kernels(${\lambda}_{\tau}$) is properly calibrated considering some other operating conditions and crop conditions which are not involved in this analysis.

• Computers and Concrete
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• 제33권1호
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• pp.41-53
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• 2024

Under constant and cyclic axial compression, square composite short columns reinforced with Self Compacting Concrete (SCC) added with scrap rubber infilled inside steel tubes and with different types of concrete were cast and tested. The test is carried out to find the effectiveness of utilizing an aggregate manufactured from industrial waste and to address the problems associated with the need for alternative reinforcements along with waste management. The main testing parameters are the type of concrete, the effect of fiber inclusion, and the significance of rubber-infilled steel tubes. The failure modes of the columns and axial load-displacement curves of the steel tube-reinforced columns were all thoroughly investigated. According to the test results, all specimens failed due to compression failure with a longitudinal crack along the loading axis. The fiber-reinforced column specimens demonstrated improved ductility and energy absorption. In comparison to the normal-weight concrete columns, the lightweight concrete columns significantly improved the axial load-carrying capacity. The addition of basalt fiber to the columns significantly increased the yield stress and ultimate stress to 9.21%. The corresponding displacement at yield load and ultimate load was reduced to 10.36% and 28.79%, respectively. The precision of volumetric information regarding the obtained crack quantification, aggregates, and the fiber in concrete is studied in detail through image processing using MATLAB environment.

• Advances in nano research
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• 제16권3호
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• pp.273-288
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• 2024

The geometrical nonlinear vibrations of the gold nanoscale rod are investigated for the first time by considering the internal modals interactions using different nonlinear beam theories. This phenomenon is usually one of the important features of nonlinear vibration systems. For a more detailed analysis, the von-Karman effects, preserving all the nonlinear terms in the strain-displacement relationships of gold nanoscale rods in three displacement directions, are considered to analyze the nonlinear axial vibrations of gold nanoscale rods. It uses highly accurate analytical-numerical solutions for the clamped-clamped and clamped-free boundary conditions of nanoscale gold rods. Also, with the help of Hamilton's principle, the governing equation and boundary conditions are derived based on Eringen's theory. The influence of nonlinear and nonlocal factors on axial vibrations was investigated separately for all three theories: Simple (ST), Rayleigh (RT) and Bishop (BT). Using different theories, the effects of inertia and shear on the internal resonances of gold nanorods were studied and compared in terms of twoto-one and three-to-one internal resonances. As the nonlocal parameter of the gold nanorod increases, the maximum nonlinear amplitude occurs. So, by adding nonlocal effects in a gold nanorod, the internal modal interactions resulting from the unique structure can be enhanced. It is worth noting that shear and inertial analysis have a significant effect on internal modal interactions in gold nanorods.

• 한국전산구조공학회논문집
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• 제35권1호
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• pp.35-44
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• 2022

초고층 건물에서 수평변위 제어와 수직부재에서 발생하는 부등축소에 대한 검토가 필수적이다. 수평변위 제어를 위해 근래에 아웃리거 구조시스템과 메가 구조시스템을 횡력저항시스템으로 사용한 초고층 건물이 증가하고 있다. 또한, 부등축소로 인한 구조적 문제를 해결하기 위해 부등축소량 예측과 예측결과를 통한 시공단계에서의 보정방법이 연구되어 왔으나 부등축소에 대한 횡력저항시스템의 영향 비교는 드문 편이다. 따라서, 본 논문에서는 수평변위 제어를 위해 아웃리거 구조시스템과 메가 구조시스템을 사용한 60층 규모의 철근콘크리트 주거용 초고층 건물에 대해 시공단계해석을 통한 부등축소를 비교하고 그 영향을 분석하고자 한다. 또한, 부등축소는 비구조요소의 파손 및 구조요소에 부가하중을 유발하기도 하며 부등축소가 야기한 문제는 초고층 건물에서 중요한 부재를 손상시킬 수 있으므로 각 횡력저항시스템별로 수직부재의 부등축소에 대한 영향을 분석하였다.