• Title/Summary/Keyword: Pressure support

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Anlysis and Design of Wale in Innovative Prestressed Support(IPS) System (혁신적 프리스트레스트 가시설(IPS)공법에 적용되는 띠장의 설계 및 해석)

  • Kim, Sung-Bo;Han, Man-Yop;Kim, Moon-Young;Kim, Nak-Kyung;Ji, Tea-Sug
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.18 no.1
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    • pp.79-91
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    • 2005
  • The behaviors and design procedures of wale in innovative prestressed support(IPS) system are presented in this paper. Using the theory of the beam on elastic foundation, the member forces of the wale under initial pretension are evaluated. Choosing cable tensions as redundant forces, member forces subjected to earth pressure are calculated by the statically indeterminate analysis. The computer analysis model under uniform and non-uniform earth pressure is constructed using beam element for the IPS wale, tension-only element for cable, and compression-only element for soil. Axial forces and bending moments of IPS wale under initial pretension and design earth pressure are calculated. The combined stresses due to these axial force and bending moment are estimated to satisfy the design formula.

An Analytical Study on the Improvement of the Performance of Swivel Valve Tube Couplers (스위벨 밸브 튜브 커플러 개발을 위한 해석 연구)

  • Lee, Jun-Ho;Sung, Jae-Kyeong
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.3
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    • pp.1-6
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    • 2011
  • This study focused on the localization of swivel type tube couplers, which all depend on imports. In this study, a computer application analysis was performed using a finite element method as a preliminary study. In the major developments related to the objective of this study, the air brake system produced by car makers represents a different in the installation point of an air tank according to the type of cars or in the length and direction of its hoses and that leads to cause lots of problems. For solving such problems, the design of the major elements in a swivel type tube coupler was analyzed using a finite element method, and its validity was also verified. In the process that verifies the validity of this study, it was necessary to investigate how much external force affects the desorption of the tube support, which is the most important element in swivel type tube couplers. For achieving the investigation, a pressure test was implemented for the tube support according to the Federal Motor Vehicle Safety Standards(FMVSS). In the results of the pressure test, all samples satisfied the FMVSS. In addition, several tests were implemented by installing the sample of the developed swivel type tube coupler to an actual vehicle. In particular, rotation tests with various angles were applied by welding the swivel type coupler to an air tank through an argon welding process. In the results of the installing test for an actual vehicle, it was verified that the designed structure was determined as a structure that is able to endure the eccentric torque and deformation pressure applied to several directions that are the major problems in such fixed type tube couplers. Therefore, in the comparison of the performance of the developed product with the product of PARKER, it was possible to verify that the localized swivel type tube coupler developed in this study shows more excellent than that of the existing products by PARKER.

An Empirical Study on Factors and Degrees of EDI Diffusion (EDI의 확산 요인과 확산 정도에 관한 연구)

  • Choe, Do-Won;Shin, Seong-Yoon;Kim, Nam-Suk
    • Journal of the Korea Society of Computer and Information
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    • v.15 no.9
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    • pp.155-164
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    • 2010
  • Until now, most of studies on Electronic Data Interchange(EDI) have been focused on the introduction of EDI and the performance of EDI. But recently, there have been increasing researches on diffusion of Electronic Data Interchange. The aims of this study are twofold. First, to find the impacts of various factors on EDI diffusion, second, to examine the relationship between EDI diffusion factors and EDI diffusion degree. To accomplish those aims of study, two kinds of methodologies are adopted in the studies, First, model building by wide investigation on previous papers, Second, empirical research for finding the determinants of diffusion of EDI. The results of testing the hypotheses of this research are summarized as follows. First, The important EDI diffusion variables influencing internal diffusion of EDI consist of top management support, scope for EDI, IS sophistication, compatibility, complexity, relative advantages, competition intensity and external pressure. Second, Top management support, scope for EDI, IS sophistication, compatibility, relative advantages, competition intensity and external pressure are associated with external diffusion of EDI. We are aware of the important fact that top management support, scope for EDI, IS sophistication, compatibility, relative advantage, competition intensity and external pressure were simultaneously associated with internal and external diffusion of EDI.

Critical Fluid Velocity of Fluid-conveying Cantilevered Cylindrical Shells with Intermediate Support (중간 지지된 유체 유동 외팔형 원통셸의 임계유속)

  • Kim, Young-Wann
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.5
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    • pp.422-429
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    • 2011
  • The critical fluid velocity of cantilevered cylindrical shells subjected to internal fluid flow is investigated in this study. The fluid-structure interaction is considered in the analysis. The cantilevered cylindrical shell is supported intermediately at an arbitrary axial position. The intermediate support is simulated by two types of artificial springs: translational and rotational spring. It is assumed that the artificial springs are placed continuously and uniformly on the middle surface of an intermediate support along the circumferential direction. The steady flow of fluid is described by the classical potential flow theory. The motion of shell is represented by the first order shear deformation theory (FSDT) to account for rotary inertia and transverse shear strains. The effect of internal fluid can be considered by imposing a relation between the fluid pressure and the radial displacement of the structure at the interface. Numerical examples are presented and compared with existing results.

Strength analysis of a filtering structure for a viscoelastic flowing substance (점탄성 유동물질 여과용 필터 구조물의 강도해석)

  • 박창호;정광섭;손태원;주상우
    • Proceedings of the Korean Fiber Society Conference
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    • 1999.04a
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    • pp.300-304
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    • 1999
  • A study is strength analysis of a filtering structure for a viscoelastic flowing substance. Conventional segment type filter units comprise an assembly of two or more individual disc segments stacked at their respective hubs on a central common filtrate collection tube within a filter housing. The conventional type's leaf disc is problem that it don't support a high pressure flows. Therefore, this study develope new structure filtering model to stand a high pressure flows.

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A Phenomenological Study on Illness Experience of Patients with Pressure Ulcer (욕창 환자들의 질병 체험에 관한 현상학적 연구)

  • Yoo, Misoo;Yi, Myungsun
    • Korean Journal of Adult Nursing
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    • v.27 no.5
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    • pp.515-526
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    • 2015
  • Purpose: The purpose of this study was to describe the illness experience of patients with pressure ulcer. Methods: A phenomenological methodology was used for the study. The data were collected by individual in-depth interview with seven participants with pressure ulcer during 2013~2014. All interviews were audio-taped and verbatim transcripts were made for the analysis. The data were analyzed using Colaizzi's phenomenological method. Results: All participants had underlying disease, such as spinal paralysis and diabetes. Average period of having pressure ulcer was 18 months, ranged from 3 to 36 months. A total of seven theme clusters were derived from the analysis; unexpected wound, inherent vulnerability to infection, reversal of the treatment policy, unpleasant and strange feeling of wound, sweeping fear and helplessness, socioeconomic burden, and healing through specific actions and reflection. The participants faced various contradictory and paradoxical situations in managing their pressure ulcers as well as underlying diseases in their everyday life. However, they slowly overcome these situations by strictly practicing concrete action-oriented strategies that they have learned through suffering and appreciating miraculous wound healing. Conclusion: The results of this study can help developing a patient-specific intervention program with sufficient emotional support by providing insights of the paradoxical illness experience of patients with pressure ulcer.

Wind Tunnel Investigation of Fluctuating Pressure Inside Building (풍하중에 의한 건물내부 압력의 동적변화에 관한 연구)

  • 이경훈
    • Computational Structural Engineering
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    • v.3 no.4
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    • pp.133-141
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    • 1990
  • The nature of fluctuating air pressure inside building was studied by testing a building model in a wind tunnel. The model has a single room and a window opening. Various opening conditions were tested in both laminar uniform wind and turbulent boundary-layer wind. The RMS and the spectra of the fluctuating internal pressure were measured. The test results support a recent theory which predicts the behavior of internal pressure under high wind based on aerodynamic analysis.

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A Characteristics of Impedance Propagation by the Unsteady Flow in a Hydraulic Pipeline (유압관로의 비정상유동에 따른 임피던스 전달특성)

  • Mo Yang-Woo;Yoo Young-Tae;Na Gee-Dae;Kim Ji-Hwan
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.6
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    • pp.48-55
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    • 2004
  • Design for quite operation of fluid power system requires the understanding of noise and vibration characteristics of the system. This paper presents a dynamic response of design of hydraulic circuit. Experimental investigations on the attenuation of pressure ripple in automotive power steering hydraulic pipe line is examined. Also, a mathematical model of hydraulic pipe is p개posed to support a design of the hydraulic circuit. and the impedance characteristics of pressure ripple is analyzed. It is experimentally shown that power steering hydraulic pipe attenuates pressure ripple with high frequency.

A Study on the Dynamic Characteristics of the Gas Spring on the Automotive Application (차량 장착상태에서의 가스 스프링 동적 특성 연구)

  • Lee, Choon Tae
    • Journal of Drive and Control
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    • v.12 no.4
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    • pp.15-20
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    • 2015
  • Unlike a typical metal spring, a gas spring uses compressed gas contained in a cylinder and compressed by a piston to exert a force. A common application includes automobiles where gas spring are incorporated into the design of open struts that support the weight of tail gate. They are also used in furniture such as office chairs, and in medical and aerospace applications. The gas spring works by the application of pressurized gas (nitrogen) contained in a cylinder. The internal pressure of the gas spring greatly exceeds atmospheric pressure. This differential in pressure exists at any rod position and generates an outward force on the rod, making the gas spring extend. In this paper, we investigated the dynamic characteristics of a gas spring on an automotive tail gate system.