• Title/Summary/Keyword: linear middle section

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A Study on the Non-linear Analysis of Steel Frame with Semi-rigid Connections (반강접성을 고려한 강뼈대 구조물의 비선형 해석에 관한 연구)

  • 이종석;이상엽;김정훈
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1997.10a
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    • pp.111-118
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    • 1997
  • Generally, H-section is used for columns and beams in the middle and low building steel structure, But it has a axis and a weak axis. Thus if H-section is used for columns, the structure needs reinforcement on the weak axis. Therefore recently, square hollow section(S.H.S) is used for columns because it is able to cover the vulnerability of H-section. Structural analysis is usually executed under the assumption that connections are either ideally pinned joint or fully joint. Actually all connections are semi-rigid which possess a rotational stiffness. Therefore it can be designed economically as using the property of connections which has a rotational stiffness. This paper presents a prediction model curve which is fitted with Kishi-Chen Power Model about the behavior of connection between H-beam and S.H.S column in the previous experimental paper. It also suggests the new analysis algorithm considering the non-linear of semi-rigid connection and the geometrical non-linear under the effect of axial force.

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Numerical Investigation of Effect of Opening Pattern of Flow Control Valve on Underwater Discharge System using Linear Pump (유량제어밸브 개방형태가 선형펌프 방식 수중사출 시스템에 미치는 영향에 관한 수치적 연구)

  • Lee, Sunjoo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.22 no.2
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    • pp.255-265
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    • 2019
  • In the present study, the effect of opening patterns of a flow control valve on underwater discharge systems using a linear pump was investigated numerically. For that, a improved mathematical model was developed. The improvement is to separate a middle tank from a water cylinder because the cross-section area of the inlet of the middle tank is an important parameter. To validate the improved model, calculation results were compared with a previous study. The results showed that $2^{nd}$ order or more polynomial opening patterns had an advantage over ramp opening patterns. Higher an order of polynomial resulted in wider operating limits. An escape velocity and a maximum acceleration of underwater vehicle were affected by time derivative of the cross-section area of the flow control valve. Besides, as a velocity profile of the vehicle got closer to linearity, the escape velocity got faster and the maximum acceleration got smaller. And velocities of the vehicle and piston had similar variation trend.

A Comprehensive Development of Urban Greenery Morphs - The Analysis of Greenery Construction of the Middle Ring Line (Puxi section) of Shanghai-

  • Zhongzhai Wang;Wei Zhuang
    • Journal of the Korean Institute of Landscape Architecture International Edition
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    • no.2
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    • pp.140-146
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    • 2004
  • All-round development of urban greenery network morphology is an integrated part of urban space system. The greenbelt construction of the Middle Ring Line is capable of changing linear planning and merging the peripheral greenery construction with 3-D space design to jointly form a broad open space.

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Nonlinear Analysis of Steel Frames Using Visual Basic (Visual Basic을 이용한 강뼈대 구조물의 비선형 해석)

  • 윤영조;김선희;이종석
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.10a
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    • pp.403-410
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    • 1999
  • General1y, H-section is used for columns and beams in the middle and low steel building, But it has a strong and weak axis. Thus if H-section is used for columns, the structure needs reinforcement on the weak axis. Therefore recently, square holler section(S.H.S) is used for columns because it is able to coiler the vulnerability of H-section. Structural analysis is usually executed under the assumption that connections are either ideally pinned joint or fully rigid joint. Actually all connections are semi-rigid which possess a rotational stiffness. Therefore it can be designed economically as using the property of connections which has a rotational stiffness. This paper presents a prediction model curve which is fitted Kishi-Chen power Model about the behavior of connection between H-beam and S.H.S column. Non-linear analysis program was considered the non-linearity of semi-rigid connection and the geometrical non-linearity under the effect of axial force. It was programed by FORTRAN90 and Visual Basic.

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Drying Characteristics of Large Western Redcedar Timber During Radio Frequency/Vacuum Drying (웨스턴 레드시더 큰 정각재(正角材)의 고주파 진공 건조 특성)

  • Jung, Hee-Suk;Avramidis, Stavros;Cai, Liping
    • Journal of the Korean Wood Science and Technology
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    • v.26 no.3
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    • pp.1-8
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    • 1998
  • Western redcedar timber, 26 by 26cm in cross section and by 200cm long, was dried in a laboratory radio-frequency/vacuum kiln under 65torr of ambient pressure and a fixed frequency of 6.78MHz for the potential rapidly dry large timber. All process data were collected and saved in a computer through a data acquisition system. The temperature in the middle of timber was higher than temperature at the quarter point of timber length and thickness. Temperature gradients developed in the longitudinal and transverse direction of timber. The pressure in the middle of timber was higher than pressure at the quarter point of timber length. The pressure in the middle of timber was lower in the early stage of drying, and higher in the latter stage of drying than pressure at the quarter point of timber thickness. Power density was very highest during heating period and then gradually decreased. The drying curve was approximately linear and the total drying time was 27 hours from an initial moisture content(MC) of 48.6 percent to a final Me of 19.2 percent with only a few mild internal checks in the middle location of timber.

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Drive Investigation of the Discontinuous Primary Linear Synchronous Motor in the Re-accelerator (1차측 분산 배치 리니어 동기 모터의 재가속부에서의 구동 고찰)

  • Kim Yong-jae;Um Yong-su;Watada Masaya;Torii Susumu;Ebihara Daiki
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.797-799
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    • 2004
  • The discontinuous primary linear synchronous motor is proposed as a driving source in the middle-distance transportation systems in factories and facilities. This paper describes the examination about the acceleration characteristics and a synchronizing method when the secondary mover overlaps with the primary from the inertia travel motion section in the whole of the re-acceleration part.

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Flexible multimode pressure sensor based on liquid metal

  • Zhou, Xiaoping;Yu, Zihao
    • Smart Structures and Systems
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    • v.28 no.6
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    • pp.839-853
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    • 2021
  • In this paper, a novel multimode liquid metal-based pressure sensor is developed. The main body of the sensor is composed of polydimethylsiloxane (PDMS) elastomer. The structure of the sensor looks like a sandwich, in which the upper structure contains a cylindrical cavity, and the bottom structure contains a spiral microchannel, and the middle partition layer separates the upper and the bottom structures. Then, the liquid metal is injected into the top cavity and the bottom microchannel. Based on linear elastic fracture mechanics, the deformation of the microchannel cross-section is theoretically analyzed. The changes of resistance, capacitance, and inductance of the microchannel under pressure are deduced, and the corresponding theoretical models are established. The theoretical values of the pressure sensor are in good agreement with experimental data, implying that the developed theoretical model can explain the performance of the sensor well.

Statistical Analysis on Microcrack Length Distribution in Tertiary Crystalline Tuff (제3기 결정질 응회암에서 발달하는 미세균열의 길이 분포에 대한 통계적 분석)

  • Park, Deok-Won
    • The Journal of the Petrological Society of Korea
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    • v.20 no.1
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    • pp.23-37
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    • 2011
  • The scaling properties on the length distribution of microcrack populations from Tertiary crystalline tuff are investigated. From the distribution charts showing length range with 15 directional angles and five groups(I~V), a systematic variation appears in the mean length with microcrack orientation. The distribution charts are distinguished by the bilaterally symmetrical pattern to nearly N-S direction. The whole domain of the length-cumulative frequency diagram for microcrack populations can be divided into three sections in terms of phases of the distribution of related curves. Especially, the linear middle section of each diagram of five groups represents a power-law distribution. The frequency ratio of linear middle sections of five groups ranges from 46.6% to 67.8%. Meanwhile, the slope of linear middle section of each group shows the order: group V($N60{\sim}90^{\circ}E$, -2.02) > group IV($N20{\sim}60^{\circ}E$, -1.55) > group I($N60{\sim}90^{\circ}W$, -1.48), group II($N10{\sim}60^{\circ}W$, -1.48) > group III($N10^{\circ}W{\sim}N20^{\circ}E$, -1.06). Five sub-populations(five groups) that closely follow the power-law length distribution show a wide range in exponents( -1.06 - -2.02). These differences in exponent among live groups emphasizes the importance of orientation effect. In addition, breaks in slope in the lower parts of the related curves represent the abrupt development of longer lengths, which is reflected in the decrease in the power-law exponent. Especially, such a distribution pattern can be seen from the diagram with $N10{\sim}20^{\circ}E,\;N10{\sim}20^{\circ}W$ and $N60{\sim}70^{\circ}W$ directional angles. These three directional angles correspond with main directions of faults developed around the study area. The distribution chart showing the individual characteristics of the length-cumulative frequency diagrams for 15 directional angles were made. By arraying above diagrams according to the categories of three groups(A, B and C), the differences in length-frequency distributions among these groups can be easily derived. The distribution chart illustrates the importance of analysing microcrack sets separately. From the related chart, the occurrence frequency of shorter microcracks shows the order: group A > group B > group C. These three types of distribution patterns could reveal important information on the processes occurred during microcrack growth.

Software for application of Newton-Raphson method in estimation of strains in prestressed concrete girders

  • Gocic, Milan;Sadovic, Enis
    • Computers and Concrete
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    • v.10 no.2
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    • pp.121-133
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    • 2012
  • Structures suffer from damages in their lifetime due to time-dependant effects, such as fatigue, creep and shrinkage, which can be expressed by concrete strains. These processes could be seen in the context of strain estimation of pre-stressed structures in two phases by using numerical methods. Their aim is checking and validating existing code procedures in determination of deformations of pre-tensioned girders by solving a system of nonlinear equations with strains as unknown parameters. This paper presents an approach based on the Newton-Raphson method for obtaining the stresses and strains in middle span section of pre-stressed girders according the equilibrium state.

Sensitivity Analysis on the Lateral Behavior of Diagrid Structure (다이아그리드 구조 시스템의 횡적 거동에 대한 민감도 해석)

  • Ahn, Keun-Woo;Yang, Jae-Kwang;Park, Sung-Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.3
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    • pp.73-82
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    • 2015
  • In evaluating lateral behavior on the seismic and wind load, the purpose of sensitivity analysis is to find critical variables and to identify characteristic response with variability of variables. The sensitivity analysis is very important in structural diagnosis, repair and reinforcement field. This study investigates the sensitivity by linear static analysis applying the TDA method in changing angles of diagrid braces on the same height structures. In case of mid rise model, under the seismic load, the brace member is determined as a major variable at $58^{\circ}$ but a high rise model, under the wind load, has the brace member as a major variable at $67.4^{\circ}$. In addition, location of critical sensitivity on the mid rise model is distributed over middle section, while it is distributed lower section on the high rise model.