• Title/Summary/Keyword: governing design factors

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Design of High Speed Solenoid Actuator for Hydraulic Servo Valve Operation

  • Sung, Baek-Ju;Kim, Do-Sik
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.2
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    • pp.239-245
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    • 2013
  • Modern electric controlled valves are demanded that its solenoid actuator should be smaller size, lighter weight, lower consumption power, and higher response time. For achieving these purposes, the major design factors of solenoid actuator such as magnetic flux density, coil turn numbers, plunger size, bobbin dimension, and etc. are must be optimized. In this study, for optimal design of high speed solenoid actuator for hydraulic servo valve operation, we draw up governing equations which are composed by combination of electromagnetic theories and empirical knowledge, and deduct the values of major design factors by use of them. For more increase the operating speed, voice coil are used as main armature in manufacturing of prototype actuator. And, we have proven the propriety of the governing equations and speed increasing method by experiments using the hydraulic valve assembly adopted the prototype of solenoid actuator.

Governing Design Factors of GFRP-Reinforced Concrete Bridge Deck (GFRP 근 보강 콘크리트 교량 바닥판의 설계지배인자)

  • Cho, Jeong-Rae;Park, Young Hwan;Park, Sung Yong;Cho, Kunhee;Kim, Sung Tae
    • Journal of the Korean Society of Safety
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    • v.30 no.6
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    • pp.70-77
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    • 2015
  • In this study, the governing design factors of GFRP-reinforced concrete bridge deck are analyzed for typical bridges in Korea. The adopted bridge deck is a cast-in-situ concrete bridge deck for the prestressed concrete girder bridge with dimensions of 240 mm thickness and 2.75 m span length from center-to-center of supporting girders. The selected design variables are the diameters of GFRP rebar, spacings of GFRP rebars and concrete cover thicknesses, Considering the absence of the specification relating GFRP rebar in Korea, AASHTO specification is used to design the GFRP-reinforced concrete bridge deck. The GFRP-reinforced concrete bridge deck is proved to be governed by the criteria about serviceability, especially maximum crack width, while steel reinforced concrete bridge deck is governed by the criteria on ultimate limit state. In addition, GFRP rebars with diameter of 16 mm ~ 19 mm should be used for the main transverse direction of decks to assure appropriate rebar spacings.

A Design of High-Speed Linear Actuator for Valve (밸브 구동용 고속 리니어 액추에이터)

  • Sung, B.J.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.8 no.1
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    • pp.1-9
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    • 2011
  • The main design factors which effect on operating speed of linear actuator for valve operation are mass of plunger, electromagnetic motive force, inductance, and return spring, and these factors are not independent but related with each other in view point of design and electromagnetic theory. It is impossible to increase the operating speed by only change the value of any one design factor. The change of any one value results in change of any value related it in various design factors. This paper presents a speed increasing method of linear actuator using a solenoid design method by some governing equations which are composed of electromagnetic theory and empirical knowledge and permanent magnets as assistant material, and proved the propriety by experiments.

Evaluation of Reliability Index of Governing Load Combination for Design of Cable Supported Bridge Members (케이블교량의 부재 설계를 지배하는 하중조합에 대한 신뢰도지수 평가)

  • Paik, Inyeol;Yoon, Taeyong
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.6
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    • pp.643-651
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    • 2014
  • In this paper the reliability analyses of the cable-supported bridge design code which is recently issued in Korea are performed and the results are presented. Governing load combinations for the member design and the statistical properties of the main members are introduced and the analysis is performed using an example cable-stayed bridge for which the design is performed following the load and resistance factors defined in the design code. The reliability analysis shows the target reliability index can be achieved by applying load and resistance factors and the application of the resistance modification factor can enhance the reliability level if the importance of the bridge needs to be increased. The sensitivity analysis reveals that decreasing uncertainty of the cable strength is critical for obtaining the target reliability index. The study results show that the design using the load and resistance factors of the code can achieve the target reliability indexes for the design of cable supported bridge.

A Study on the Axis Line of Short Span Filled Spandrel Arch Bridge (단경간 폐복식 아치교의 축선에 관한 연구)

  • 구민세;황윤국;조현준
    • Proceedings of the Korea Concrete Institute Conference
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    • 1990.10a
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    • pp.95-100
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    • 1990
  • The behavior of short span filled spandrel arch bridge of 10 and 21 m span with various axis line, rise and backill height were investigated under the design loads(self weight, earth pressure, temperature load, live load, etc). Even though the behaviors of arch were known as relatively complicated, the followings can be concluded within the limits of this study. The design value of arch bridge increase as the rise decreases, the effects of temperature load become dominant for the design of arch bridge, and governing design factors are occured at springing.

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A Study on the Formation Factors of Grotesque Image expressed in Fashion (복식에 표현된 그로테스크 이미지의 형성 요인에 관한 연구)

  • 남미현
    • Journal of the Korea Fashion and Costume Design Association
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    • v.4 no.3
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    • pp.43-54
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    • 2002
  • Some factors had influence upon the grotesque image formation expressed in fashion: for instance, thanatos, religions, fin de siecle (end of the century), the aesthetics of ugliness, subculture group's resistance and technology development, etc. Those factors have formed a grotesque while exchanging influence each other, and have following features: First, the thanatos, which is destructive and aggressive instinct of the inner world of human being, creates frightening object and motif to form the images of grotesque. Second, from religious point of view, the church made the Devil a tool for maintenance of power: They manipulated physical body and give a damage to it to sublimate it in holy existence, so that they could feel catharsis. Third, there was fin de siecle (end of the century) to let people have negative life attitude, such as uneasiness on following century, eschatology, skepticism and nihilism, etc. Fourth, the ugliness having unpleasantness and disharmony occupies governing position when our society becomes corrupted and uneasy, and the aesthetics of ugliness discloses the inconsistency of ideal and beautiful life in the grotesque images. Fifth, subculture groups, i.e., the lower classes, homosexual and the youth's group, etc, form the grotesque images by political and ideological resistance, complaints and specific identity, etc concerning governing culture keeping traditional ethics consciousness. Sixth, recent technology development has destroyed a boundary between human being and machinery, and bio-technology development has created transplant operation, plastic operation and other human body transformation operations, and genome research, etc has raised human being's identity.

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Evaluation of static response in stress-ribbon concrete pedestrian bridges

  • Stavridis, Leonidas T.
    • Structural Engineering and Mechanics
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    • v.34 no.2
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    • pp.213-229
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    • 2010
  • An analytical method is proposed for the evaluation of the static response of a prestresse-dribbon concrete pedestrian bridge, which may also be applied for the roofing of large areas. On the basis of an established analogy with a suspension bridge system, a procedure is presented for the prestresse-dribbon direct analysis, leading to the introduction of two dimensionless parameters as governing factors of the design, namely the thinness and the prestressing steel ratio. The exposed procedure, applied by a simple computer program, allows a quick evaluation of the response and permits the investigation of the influence of the aforementioned parameters on it, by means of comprehensive diagrams. The presented diagrams may be directly used for the preliminary design of a pedestrian bridge of this type, for the whole practical range of span lengths. A design example is also included, showing the applicability of the proposed procedure.

Factors governing dynamic response of steel-foam ceramic protected RC slabs under blast loads

  • Hou, Xiaomeng;Liu, Kunyu;Cao, Shaojun;Rong, Qin
    • Steel and Composite Structures
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    • v.33 no.3
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    • pp.333-346
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    • 2019
  • Foam ceramic materials contribute to the explosion effect weakening on concrete structures, due to the corresponding excellent energy absorption ability. The blast resistance of concrete members could be improved through steel-foam ceramics as protective cladding layers. An approach for the modeling of dynamic response of steel-foam ceramic protected reinforced concrete (Steel-FC-RC) slabs under blast loading was presented with the LS-DYNA software. The orthogonal analysis (five factors with five levels) under three degrees of blast loads was conducted. The influence rankings and trend laws were further analyzed. The dynamic displacement of the slab bottom was significantly reduced by increasing the thickness of steel plate, foam ceramic and RC slab, while the displacement decreased slightly as the steel yield strength and the compressive strength of concrete increased. However, the optimized efficiency of blast resistance decreases with factors increase to higher level. Moreover, an efficient design method was reported based on the orthogonal analysis.

Effect of boundary mobility on nonlinear pulsatile-flow induced dynamic instability of FG pipes

  • Zhoumi Wang;Yiru Ren;Qingchun Meng
    • Structural Engineering and Mechanics
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    • v.86 no.6
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    • pp.751-764
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    • 2023
  • In practical engineering such as aerial refueling pipes, the boundary of the fluid-conveying pipe is difficult to be completely immovable. Pipes under movable and immovable boundaries are controlled by different dominant nonlinear factors, where the boundary mobility will affect the nonlinear dynamic characteristics, which should be focused on for adopting different strategies for vibration suppression and control. The nonlinear dynamic instability characteristics of functionally graded fluid-conveying pipes lying on a viscoelastic foundation under movable and immovable boundary conditions are systematically studied for the first time. Nonlinear factors involving nonlinear inertia and nonlinear curvature for pipes with a movable boundary as well as tensile hardening and nonlinear curvature for pipes with an immovable boundary are comprehensively considered during the derivation of the governing equations of the principal parametric resonance. The stability boundary and amplitude-frequency bifurcation diagrams are obtained by employing the two-step perturbation- incremental harmonic balance method (TSP-IHBM). Results show that the movability of the boundary of the pipe has a great influence on the vibration amplitude, bifurcation topology, and the physical meanings of the stability boundary due to different dominant nonlinear factors. This research has guidance significance for nonlinear dynamic design of fluid-conveying pipe with avoiding in the instability regions.

Nonlinear wind-induced instability of orthotropic plane membrane structures

  • Liu, Changjiang;Ji, Feng;Zheng, Zhoulian;Wu, Yuyou;Guo, Jianjun
    • Wind and Structures
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    • v.25 no.5
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    • pp.415-432
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    • 2017
  • The nonlinear aerodynamic instability of a tensioned plane orthotropic membrane structure is theoretically investigated in this paper. The interaction governing equation of wind-structure coupling is established by the Von $K\acute{a}rm\acute{a}n's$ large amplitude theory and the D'Alembert's principle. The aerodynamic force is determined by the potential flow theory of fluid mechanics and the thin airfoil theory of aerodynamics. Then the interaction governing equation is transformed into a second order nonlinear differential equation with constant coefficients by the Bubnov-Galerkin method. The critical wind velocity is obtained by judging the stability of the second order nonlinear differential equation. From the analysis of examples, we can conclude that it's of great significance to consider the orthotropy and geometrical nonlinearity to prevent the aerodynamic instability of plane membrane structures; we should comprehensively consider the effects of various factors on the design of plane membrane structures; and the formula of critical wind velocity obtained in this paper provides a more accurate theoretical solution for the aerodynamic stability of the plane membrane structures than the previous studies.