• Title/Summary/Keyword: maximum deflection

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Evaluation of Cracking Strength of Floating Floor System (뜬바닥구조의 균열강도 평가)

  • Lee, Jung-Yoon;Lee, Bum-Sik;Jun, Myoung-Hoon;Kim, Jong-Mun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.1
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    • pp.53-61
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    • 2015
  • This paper reports the test results of the floating floor system used to reduce the floor noise of apartment buildings. Recently, many soft resilient materials placing between the reinforced concrete slab and finishing mortar are used. The resilient material should not only reduce the floor impact sound vibration from the floor but also support the load on the floor. Thus, even if soft resilient materials satisfy the maximum limitation of light-weight impact sound and heavy-weight impact sound, these materials may not support the load on the floor. The experimental program involved conducting sixteen sound insulation floating floor specimens. Three main parameters were considered in the experimental investigation: resilient materials, loading location, and layers of floor. Experimental results indicated that the stiffness of resilient material significantly influenced on the structural behavior of floating floor system. In addition, the deflection of the floating concrete floor loaded at the side or coner of the specimen was greater than that of the floor loaded at the center of the specimen. However, the aerated concrete did not effect on the cracking strength of floating floor system.

Six Sigma based on Robust Design of Gripper for LCD Transfer System (LCD 이송장치의 그립퍼부 시그마 기반 강건설계)

  • Chung W.J.;Jung D.W.;Kim H.J.;Yoon Y.M.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.361-362
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    • 2006
  • This paper presents the robust design of gripper part for a high-speed LCD (Liquid Crystal Display) transfer system. In this paper, the 1st DOE (Design of Experiment) is conducted to find out main-effect factors fur the design of gripper part. Thirty-six experiments are performed using $ANSYS^{(R)}$ and their results are statistically analyzed using $MINITAB^{(R)}$, which shows that the factors, i.e., First-width, Second-width, Rec-width, and thickness of gripper part, are more important than other factors. The main effect plots shows that the maximum deflection and mass of gripper part are minimized by increasing First-width, Second-width, Rec-width and thickness. The 2nd DOE is conducted to obtain RSM (Response Surface Method) equation. The CCD (Central Composite Design) technique with four factors is used. Optimum design is conducted using the RSM equation. Genetic algorithm is used for optimal design. Six sigma robust design is conducted to find out a guideline for control range of design parameter. To obtain six sigma level reliability, the standard deviations of design parameters are shown to be controlled within 5% of average design value.

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The Development of Advanced Buckling Strength Estimation System (선박 판부재의 개선된 좌굴평가 시스템의 개발)

  • Ham, J.H.;Kim, U.N.
    • Journal of the Society of Naval Architects of Korea
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    • v.34 no.3
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    • pp.53-60
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    • 1997
  • Generally, a safety estimation based on the buckling strength is carried out to evaluate the strength of plate members in the design process of ship hull structures and more accurate and efficient tool for the buckling strength estimation of enormous plate members of ship structure is naturally demended for saving design process. While, in the reason that the design codes of classification societies do not consider the various effects or include some effects roughly, considerate safe side results are suggested occasionally. In this study, advanced buckling strength estimation system prepared various classification buckling evaluation codes and new evaluation code considering the effects of in-plane tension, plate boundary condition, lateral load & residual stress is developed using the window management system of engineering workstation. Additionally maximum deflection estimation formula is equipped for the increase of fabrication reliability of thin plate ship structure. From this evaluation system, more reliable buckling safety of plate panel will be guaranteed in the ship hull design stage. In order to expand the use of this system pc version system will be developed sooner or later.

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A Study on the Life Prediction and Quality Improvement of Joint in IC Package (플라스틱 IC 패키지 접합부의 수명예측 및 품질향상에 관한 연구)

  • 신영의;김종민
    • Journal of Welding and Joining
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    • v.17 no.1
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    • pp.124-132
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    • 1999
  • Thermal fatigue strength of the solder joints is the most critical issue for TSOP(Thin Small Outline Package) because the leads of this package are extremely short and thermal deformation cannot be absorbed by the deflection of the lead. And the TSOP body can be subject to early fatigue failures in thermal cycle environments. This paper was discussed distribution of thermal stresses at near the joint between silicon chip and die pad and investigated their reliability of solder joints of TSOP with 42 alloy clad lead frame on printed circuit board through FEM and 3 different thermal cycling tests. It has been found that the stress concentration around the encapsulated edge structure for internal crack between the silicon chip and Cu alloy die pad. And using 42 alloy clad, The reliability of TSOP body was improved. In case of using 42 alloy clad die pad(t=0.03mm). $$\sigma$_{VMmax}$ is 69Mpa. It is showed that 15% improvement of the strength in the TSOP body in comparison with using Cu alloy die pad $($\sigma$_{VMmax}$=81MPa). In solder joint of TSOP, the maximum equivalent plastic strain and Von Mises stress concentrate on the heel of solder fillet and crack was initiated in it's region and propagated through the interface between lead and solder. Finally, the modified Manson-Coffin equation and relationship of the ratio of $N_{f}$ to nest(η) and cumulative fracture probability(f) with respect to the deviations of the 50% fracture probability life $(N_{f 50%})$ were achieved.

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Preparation of Self-reinforced Silicon Carbide Ceramics by Hot Pressing (가압소결에 의한 자체강화 탄화규소 세라믹스의 제조)

  • Park, Jong-Gon;Lee, Jong-Kook;Seo, Dong-Seok;Kim, Min-Jeong;Lee, Eun-Gu;Kim, Hwan
    • Journal of the Korean Ceramic Society
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    • v.36 no.12
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    • pp.1356-1363
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    • 1999
  • Self-reinforced silicon carbide was prepared by hot pressing and the control of starting phases of raw materials and its microstructural characteristics was investigated. The specimens with self-reinforced microstructure were obtained from the compacts with mixed compositions of ${\alpha}$-and ${\beta}$-SiC powders. Self-reinforced microstructure which is composed of large dispersed grains with rod-like shape and matrix with small equiaxed grains was formed by the transformation to the ${\alpha}$-SiC with 4H polytype for ${\beta}$-SiC and anisotropic grain growth during the heat treatment. Of all speimens the values of volume fraction maximum length and aspect ratio for large grains with rode-like types were the highest at the specimen with 50 vol% ${\beta}$-SiC in the starting SiC powder and therefore this specimen showed the highest fracture toughness due to the crack deflection by rod-like grains during crack propagation.

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Minimum Cost Design of Reinforced Concrete Beam Using DCOC (DCOC를 이용한 철근 콘크리트보의 최소경비설계)

  • 조홍동;한상훈
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.13 no.4
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    • pp.417-425
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    • 2000
  • This paper describes the application of discretized continuum-type optimality criteria(DCOC) and the development of optimum design program for the reinforced concrete continuous beams with rectangular cross-section. The cost of construction as objective function which includes the costs of concrete, reinforcing steel and formwork is minimized. The design constraints include limits on the maximum deflection, flexural and shear strengths, in addition to ductility requirements, and upper and lower bounds on design variables as stipulated by the design Code. Based on Kuhn-Tucker necessary conditions, the optimality criteria are explicitly derived in terms of the design variables-effective depth, and steel ratio. The self-weight of the beam is included in the equilibrium equation of the real system. An iterative procedure and computer program for updating the design variables are developed. Two numerical examples of reinforced concrete continuous beams are presented to show the applicability and efficiency of the DCOC-based technique.

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Effect of Seismic Design Details in Reinforced Concrete Beams on Blast-Resistance Performance (철근콘크리트 보의 내진 설계 상세가 폭발 저항 성능에 미치는 영향)

  • Kim, Kuk-Jae;Kim, Han-Soo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.5
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    • pp.427-434
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    • 2017
  • Recently, awareness of the public about the explosion damage has increased due to the increased risk of terrorism. The criteria for blast-resistance design is not sufficient in Korea, it is necessary to develop blast-resistance design for the stability and safety of building by static analysis of current blast-resistance design. In addition, as the increase of earthquake occurrence necessitates the seismic design, it is studied to judge the blast-resistance performance of members applying seismic design without blast-resistance design. Currently, the general analysis of blast load is to refer to UFC 3-340-02 manual. Blast-resistance performance was studied by applying characteristics of blast load through UFC 3-340-02 manual, beam converted into equivalent SDOF System. It is proved that blast-resistance performance is improved when seismic detail is applied considering the maximum deflection of normal, intermediate, and special moment frames.

A Study of Circulating Water Channel (회유수조 제작 및 시험에 관한 연구)

  • CHANG Jee Won;HA Kang Lyeol;LEE Woon Hee
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.18 no.1
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    • pp.8-14
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    • 1985
  • A circulation water channel with observational section of $4m{\times}2.4m{\times}1m(length{\times}breadth{\times}depth)$ and the maximum channel flow speed of 2 m/sec was designed for model tests of fishing gears. It consists of 6 sections evenly divided for easy connection. Two observational acryl windows of $1.2m{\times}1.5m$ and 2cm thick are provided. Steel deflection plates, equally spaced in 20-40cm, are fixed at corners of the channel to reduce the loss of water pressure head through the channel. The flow in the channel is controlled by D.C. motor control system with 50 H.P. driving propeller system. A series of model testing capabilities for fishing gear have been examined and the results are as follows. 1) The speed of water flow was in the range from zero to 2.3 m/sec. 2) The difference between the velocity of channel flow along the center line and that along both sides in the channel was less than 0.2 m/sec.

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Estimating Fatigue Life of APD Electronic Equipment for Activation of a Spaceborne X-band 2-axis Antenna (2축 짐벌식 X-band 안테나 구동용 전장품 APD 제어보드의 피로수명 평가)

  • Jeon, Young-Hyeon;Oh, Hyun-Ung
    • Journal of Aerospace System Engineering
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    • v.11 no.1
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    • pp.1-7
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    • 2017
  • While a satellite is carried into orbit by a launch vehicle, it is exposed to the severe launch environment with random vibrations and shock. Accordingly, these vibration sources affect electronic equipment, particularly the printed circuit board (PCB) in the satellite. When the launch load impacts the PCB, it causes negative behavior. This causes perpendicular bending around the boundary of fixation points that finally leads to the failure of solder joints, lead wires, and PCB cracks. To overcome these issues, the electronic equipment design must meet reliability requirements. In this paper, Steinberg's method is used to derive allowable and maximum deflection to verify design from a life perspective concerning the control board of the Antenna Pointing Driver (APD) mounted on KOMPSAT-3.

Conceptual Structural Design Method in Integrated Design System for Tall Buildings (초고층건물의 통합설계시스템에서 개념구조설계법 개발)

  • Song, Hwa-Cheol;Cho, Yong-Soo
    • Journal of Korean Association for Spatial Structures
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    • v.5 no.3 s.17
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    • pp.75-82
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    • 2005
  • The conceptual structural design consists of selecting structural material and form of the building, producing a preliminary dimensional layout. The information such as height of the building use, typical live load, wind velocity, design acceleration, maximum lateral deflection, span, story height is a important factor in conceptual design phase. In this case, the knowledge solutions for past similar problems cam be used in the process of defining and finding a solution to the design problems. In this paper, the conceptual structural design method using case-based reasoning which is intended to assist engineers in the conceptual phase of the structural design of tall buildings is introduced. Inductive retrieval method and nearest-neighbor retrieval method are used for selecting structural system and similar design case, respectively.

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