• Title/Summary/Keyword: combined loads

검색결과 490건 처리시간 0.024초

A Response Estimation for Vehicle Vibration of Gas Pipeline (가스 파이프라인의 차량진동 응답 예측)

  • 박선준;박연수;강성후
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • 제14권1호
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    • pp.40-49
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    • 2004
  • In this paper, vibration response of aerial gas pipeline due to vehicle loads was quantitatively estimated through experiment and analysis in open cut construction site. The vehicle vibration of various construction machines causes serious effect to the aerial gas pipeline. The new vibration prediction equations presented in this study can estimate the vibration velocity response of the aerial gas pipeline. In the nitration prediction equations, the vehicle′s weight and traveling velocity, which are the sources of vibration, are combined into the term called, "scaled weight" Methods to reduce vibration were proposed in case the vibration velocity response of the gas pipeline exceeded the vibration criterion, using the vibration prediction equations presented in this study. One was to limit the vehicle′s traveling velocity and the other to install the isolation equipment. Both methods can be estimated quantitatively.

Study on the determination of optimum size of storage tank and intercepting capacity for CSOs reduction in urban area (도시지역 CSOs 저감을 위한 저류조 및 이송관로의 최적 용량결정에 관한 연구)

  • Lee, Kwan Yong;Choi, Won Suk;Lee, Yong Jae;Koo, Won Suk;Song, Chang Soo
    • Journal of Korean Society of Water and Wastewater
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    • 제26권6호
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    • pp.735-745
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    • 2012
  • Storage method is one of major measures for reduction of CSOs pollutant loads and several projects have been done nationwide. But systematic analysis of intercepting capacity has not been studied to determine optimum size of storage facility. In this research, not only storage volume but also intercepting capacity which means flow capacity from intercepting facility to CSOs storage facility was studied and optimum sizing method for storage facility was proposed. The result shows that pollutants reduction efficiency can be increased significantly by increasing intercepting capacity and it might reduce storage volume and total construction costs. Intercepting capacity for the study area was evaluated and it was shown as equivalent to 83 % probability rainfall intensity.

Nonlinear Transient Responses of Isotropic Plates Under Thermo-Acoustic Load (열-음향 복합하중에 놓인 등방성 평판의 비선형 응답특성)

  • Oh, Il-Kwon;Cheng, Tai-Hong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 한국소음진동공학회 2006년도 추계학술대회논문집
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    • pp.235-238
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    • 2006
  • For high-speed aircraft and high-speed civil transport planes, certain structural skin components are subjected to very large acoustic loads in an elevated thermal environment. In this study, we used the single-mode Fokker-Panck distribution to predict displacements of isotropic plates subject to thermo-acoustic combined load. The single mode was formulated to predict the nonlinear dynamic responses of postbuckled plates under acoustic random excitation. Acoustic random excitation was used with Gauss distribution. Some important effects of the snap-through motion on the dynamic responses of the postbuckled plates are described.

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Shear Resistant Mechanism into Base Components: Beam Action and Arch Action in Shear-Critical RC Members

  • Jeong, Je-Pyong;Kim, Woo
    • International Journal of Concrete Structures and Materials
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    • 제8권1호
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    • pp.1-14
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    • 2014
  • In the present paper, a behavioral model is proposed for study of the individual contributions to shear capacity in shear-critical reinforced concrete members. On the basis of the relationship between shear and bending moment (V = dM/dx) in beams subjected to combined shear and moment loads, the shear resistant mechanism is explicitly decoupled into the base components-beam action and arch action. Then the overall behavior of a beam is explained in terms of the combination of these two base components. The gross compatibility condition between the deformations associated with the two actions is formulated utilizing the truss idealization together with some approximations. From this compatibility condition, the ratio of the shear contribution by the tied arch action is determined. The performance of the model is examined by a comparison with the experimental data in literatures. The results show that the proposed model can explain beam shear behavior in consistent way with clear physical significance.

AC and DC Microgrids: A Review on Protection Issues and Approaches

  • Mirsaeidi, Sohrab;Dong, Xinzhou;Shi, Shenxing;Wang, Bin
    • Journal of Electrical Engineering and Technology
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    • 제12권6호
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    • pp.2089-2098
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    • 2017
  • Microgrid is a convenient, reliable, and eco-friendly approach for the integration of Distributed Generation (DG) sources into the utility power systems. To date, AC microgrids have been the most common architecture, but DC microgrids are gaining an increasing interest owing to the provision of numerous benefits in comparison with AC ones. These benefits encompass higher reliability, power quality and transmission capacity, non-complex control as well as direct connection to some DG sources, loads and Energy Storage Systems (ESSs). In this paper, main challenges and available approaches for the protection of AC and DC microgrids are discussed. After description, analysis and classification of the existing schemes, some research directions including coordination between AC and DC protective devices as well as development of combined control and protection schemes for the realization of future hybrid AC/DC microgrids are pointed out.

Performance Evaluation of the Wall-Type BIPV System Based on the Energy Consumption Unit - A Study for University Lecture Building - (에너지 소비 원단위를 기초로 한 벽면부착형 BIPV 시스템의 성능평가에 관한 연구 - 대학교 강의동 건축물을 대상으로 -)

  • Lee, Kang-Guk;Seo, Won-Duck;Hong, Won-Hwa
    • Journal of the Korean Institute of Educational Facilities
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    • 제18권6호
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    • pp.25-32
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    • 2011
  • The building integrated photovoltaic(BIPV) system has a double advantage that it reduces costs for exterior materials and PV panels. It allows the construction of a low-energy building without the need for the additional installation space. At the construction planning stage, however, it requires sufficient evaluation on the efficiency and performance. This study was performed to promote the distribution of photovoltaic power generation system by estimating the potential photovoltaic power generation capacity of the BIPV system installed on the university lecture building and by evaluating the characteristics and performances of window, spandrel and combined attachment types via the simulation of generation capacity per unit area.

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Experimental Study on Simple Dimensionless Parameter in Higher Pair (점접촉에서 단무차원매개변수에 관한 실험적 연구)

  • 김경모
    • Journal of the Korean Society of Safety
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    • 제9권3호
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    • pp.34-40
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    • 1994
  • It is important to have exact informations on the real contact mechanism between spheres and rough plates under various normal loads, sphere diameters and combined surface roughnesses. Most previous papers have proposed the questions of the errors which might be incurred when the Hertzian theory is used to calculated the contact deformation and the contact pressure of practical higher pair. So, this study investigates the real contact deformation between a rough sphere and a rough plate by three experimental methods far from any assumptions and theorems. The soot coating method among them is used successfully. Accordingly, this study presents the simple dimensionless parameter to predict such errors to occur in the design of high pair members and to govern the real mechanism of two-body higher pair.

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Improvement to Crack Retardation Models Using ″Interactive Zone Concept″

  • Lee, Ouk-Sub;Chen, Zhi-Wei
    • International Journal of Precision Engineering and Manufacturing
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    • 제3권4호
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    • pp.72-77
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    • 2002
  • The load interaction effect can be best illustrated by the phenomenon of overload retardation. Some prediction methods for retardation are reviewed and the problems discussed in the present paper. The so-called under-load effect much of the retardation disappears if a very low level minimum stress follows the overload, is also of importance for a prediction model to work properly under random load spectrum. The concept of Interactive Zone (IZ) fully considering reversed plasticity during unloading was discussed. This IZ concept can be combined with existing models to derive some improved models that can naturally take account of the under-load effect. Some simulations by IZ improved models for test under complex load sequences including multiple overloads and both over/under loads are compared with test results. It is seen that the improvement by IZ concept greatly enhanced the ability of existing models to accommodate complex load interaction effects.

Combined effect of nitrogen- and oxygen functional groups on electrochemical performance of surface treated multi-walled carbon nanotubes (표면처리된 탄소나노튜브의 질소 및 산소관능기 도입에 따른 전기화학적 특성)

  • Kim, Ji-Il;Park, Soo-Jin
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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    • pp.214.1-214.1
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    • 2011
  • In this work, the electrochemical properties of the surface treated multi-walled carbon nanotubes (MWNTs) are investigated for supercapacitors. Nitrogen- and oxygen functional groups containing MWNTs are prepared by nitrogen precursors and acidic treatment, respectively. The surface properties of the MWNTs are confirmed by X-ray photoelectron spectroscopy (XPS) and Zeta-potential measurements. The electrochemical properties of the MWNTs are investigated by cyclic voltammetry, impedance spectra, and charge-discharge cycling performance in 1 M $H_2SO_4$ at room temperature. As a result, these functionalized MWNTs lead to an increase in the specific capacitance as compared with the pristine MWNTs. It proposes that the pyridinic and pyridinic-N-oxides nitrogen species influence on the specific capacitance due to their positive charges, and thus an improved electron transfer at high current loads, since they are the most important functional groups affecting capacitive behaviors.

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A Study on the Hot Extrusion Dies with $TiB_2$ Insert ($TiB_2$ 인서트를 체결한 열간압출 금형에 관한 연구)

  • Kwon H. H.;Lee J. R.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 한국소성가공학회 2001년도 춘계학술대회 논문집
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    • pp.106-109
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    • 2001
  • The use of ceramic inserts in hot extrusion dies offers significant technical and economic advantages over other forms of manufacture. These potential benefits can however only be realized by optimal design of the tools so that the ceramic inserts are not subjected to stresses that lead to their premature failure. In this paper, process simulation and stress analysis are thus combined during the design, and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads. The results are compared with the experimental ones for verification.

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