• International Journal of Naval Architecture and Ocean Engineering
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• 제3권4호
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• pp.286-292
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• 2011

In order to design a shear coaxial injector of solid particles for underwater propulsion system, basic experiments on gas-liquid shear coaxial injector are necessary. In the gas-liquid coaxial injector self-pulsation usually occurs with an intense scream. When self-pulsation occurs, mass flow rate oscillation and intense scream are detected by the interactions between the liquid and gas phase. Self-pulsation must be suppressed since this oscillation may cause combustion instabilities. Considerable research has been conducted on self-pulsation characteristics, but these researches are conducted in swirl coaxial injector. The main objective of this research is to understand the characteristics of self-pulsation in shear coaxial injector and reveal the mechanism of the phenomenon. Toward this object, self-pulsation frequency and spray patterns are measured by laser diagnostics and indirect photography. The self-pulsation characteristics of shear coaxial injector are studied with various injection conditions, such as the pressure drop of liquid and gas phase, and recess ratio. It was found that the frequency of the self-pulsation is proportional to the liquid and gas Reynolds number, and proportional to the L/d.

• 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.

• 한국농공학회논문집
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• 제47권6호
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• pp.59-70
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• 2005

A series of resonant column test was performed to investigate the dynamic deformation characteristics of silty sand soils mixed with polypropylene fibrillated type fiber. Results show that optimum mixing ratios were $0.2\%$ for 19mm of cut fiber for shear modulus and $0.1\%$ for 60mm cut fiber fur damping ratio. As shear strain was increased, normalized values of shear modulus (G(Reinforced)/ G(Unreinforced)) of fiber reinforced soil were increased up to $10^{-3}\%\~10^{-1}\%$ ranges. However, normalized damping ratio (D(Reinforced/D(Unreinforced)) was diminished with an increase in strain beyond $10^{-3}\%\~10^{-1}\%$ for the damping capacity of soils mixed with fiber. Normalized shear modulus $(G/G_{max})$ obtained from the test was plotted in the chart suggested by Seed and Idriss. The shear modulus of silty sand was located between sand and gravel curves.

• Journal of Magnetics
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• 제21권2호
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• pp.244-248
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• 2016

Aiming to improve the shear yield stress of magnetorheological fluid, magnetorheological fluids with different particle characteristics are prepared, and the influence rules of particle mass fraction, particle size, nanoparticles content and application temperature on shear yield stress are investigated. Experimental results indicate that shear yield stress increases approximate linearly with the enhancement of particle mass fraction. Particle size and the nanoparticles within 10% mass fraction can improve the shear yield stress effectively. When the application temperature is higher than $100^{\circ}C$, the shear yield stress decreases rapidly because of thermal expansion and thermal magnetization effect.

• Geomechanics and Engineering
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• 제9권5호
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• pp.601-618
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• 2015

Soil-reinforcement interaction mechanism is an important issue in the design of geosynthetic reinforced soil structures. This mechanism depends on the soil properties, reinforcement characteristics and interaction between these two elements (soil and reinforcement). In this work the shear strength of sand/geotextile interfaces were characterized through direct and simple shear tests. The direct shear tests were performed on a conventional direct shear device and on a large scale direct shear apparatus. Unreinforced sand and one layer reinforced sand specimens were characterized trough simple shear tests. The interfaces shear strength achieved with the large scale direct shear device were slightly larger than those obtained with the conventional direct shear apparatus. Notwithstanding the differences between the shear strength characterization through simple shear and direct shear tests, it was concluded that the shear strength of one layer reinforced sand is similar to the sand/geotextile interface direct shear strength.

• 한국환경복원기술학회지
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• 제10권1호
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• pp.82-90
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• 2007

In order to analyse the strength problems for an unsaturated soil, it is required to examine closely the characteristics of the parameters of shear strength which was changed with the metric suction and void ratio. To this ends, a triaxial compression test was conducted on the three samples-granular soil, cohesive soil and silty soil. The specimen was made by pressing the static pressure on the mold filled soil and was controled the void ratio with the different compaction ratio. And the test was performed by using the modified apparatus of the triaxial compression tester. The range of matric suction was 0-90 kPa.The measured results for the deviator stress and parameters of shear strength were analysed with the void ratio and the compaction ratio, and they were examined closely the characteristics of the strength for an unsaturated soil.

• 대한토목학회논문집
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• 제14권1호
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• pp.195-202
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• 1994

본 연구에서는 모래의 전단파괴 포락선의 곡률특성을 구명하고 전단강도와 Been과 Jefferies가 제시한 상태정수간의 매개변수관계를 밝히기 위하여 많은 압밀배수삼축시험의 결과를 분석하였다. 통상적인 삼축시험에서 시료의 단면적 변화와 멤브레인의 영향에 대한 수정은 특히 한계상태를 결정하는데 중요하다고 할 수 있다. 실험결과로부터 전단강도를 밀도와 응력수준의 함수로 표현하는 모델을 제시하였고 모래의 전단파괴포락선의 곡률특성과 상태정수와 전단강도정수간의 관계를 밝혔다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.57.2-57.2
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• 2011

In this study, the effects of shear flows around a 2-dimensional airfoil, S809 on its aerodynamic characteristics were analyzed by CFD simulations. Various parameters including reference inflow velocity, shear rate, angle of attack, and cord length of the airfoil were examined. From the simulation results, several important characteristics were found. Shear rate in a flow makes some changes in the lift coefficient depending on its sign and magnitude but angle of attack does not have a distinguishable influence. Cord length and reference inflow also cause proportional and inversely proportional changes in lift coefficient, respectively. We adopted an analytic expression for the lift coefficient from the thin airfoil theory and proposed a modified form applicable to the traditional load analysis procedure based on the blade element momentum theory. Some preliminary results applied to an well known load simulation software, FAST, are presented.

• Steel and Composite Structures
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• 제27권6호
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• pp.761-775
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• 2018

In the present work, the recently developed non-polynomial shear deformation theories are assessed for thermo-mechanical response characteristics of laminated composite plates. The applicability and accuracy of these theories for static, buckling and free vibration responses were ascertained in the recent past by several authors. However, the assessment of these theories for thermo-mechanical analysis of the laminated composite structures is still to be ascertained. The response characteristics are investigated in linear and non-linear thermal gradient and also in the presence and absence of mechanical transverse loads. The laminated composite plates are modelled using recently developed six shear deformation theories involving different shear strain functions. The principle of virtual work is used to develop the governing system of equations. The Navier type closed form solution is adopted to yield the exact solution of the developed equation for simply supported cross ply laminated plates. The thermo-mechanical response characteristics due to these six different theories are obtained and compared with the existing results.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(I)
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• pp.587-595
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• 2002

Geotextile containers for restoration of slopes form the interface between the containers during the restored to lost slopes, and therefore the relation displacements are developed including the sliding on the surface. Since, the shear strength on these interfaces is less than that of fill material in the container, the characteristics of shear strength on the interface governs the behavior of the restoration slopes. In general, a lot of natural properties of geotexiles is required to evaluate the safty of the geotextiles, Among the properties, the shear characteristics between geotextiles and soil is a important variable to assess the safety. From the results of full scale direct shear test, the residual shear strength is recommanded to use for design factors since a large deformation possibly occures on the geotextile containers.