• Title/Summary/Keyword: Distributed-Element

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Crack Damages in Exterior Wall Structures of Korean High-Rise Apartment Buildings Based on Nonlinear Finite Element Analysis (비선형 유한요소해석 기반 국내 고층아파트 외벽구조의 균열손상 특성 분석)

  • Kim, Sung Hyun;Mo, Sang Yeong;Kim, Si Hyun;Choi, Kyoung Kyu;Kang, Su Min
    • Journal of the Earthquake Engineering Society of Korea
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    • v.28 no.1
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    • pp.47-57
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    • 2024
  • Recently, in newly constructed apartment buildings, the exterior wall structures have been characterized by thinness, having various openings, and a significantly low reinforcement ratio. In this study, a nonlinear finite element analysis was performed to investigate the crack damage characteristics of the exterior wall structure. The limited analysis models for a 10-story exterior wall were constructed based on the prototype apartment building, and nonlinear static analysis (push-over analysis) was performed. Based on the finite element (FE) analysis model, the parametric study was conducted to investigate the effects of various design parameters on the strength and crack width of the exterior walls. As the parameters, the vertical reinforcement ratio and horizontal reinforcement ratio of the wall, as well as the uniformly distributed longitudinal reinforcement ratio and shear reinforcement ratio of the connection beam, were addressed. The analysis results showed that the strength and deformation capacity of the prototype exterior walls were limited by the failure of the connection beam prior to the flexural yielding of the walls. Thus, the increase of wall reinforcement limitedly affected the failure modes, peak strengths, and crack damages. On the other hand, when the reinforcement ratio of the connection beams was increased, the peak strength was increased due to the increase in the load-carrying capacity of the connection beams. Further, the crack damage index decreased as the reinforcement ratio of the connection beam increased. In particular, it was more effective to increase the uniformly distributed longitudinal reinforcement ratio in the connection beams to decrease the crack damage of the coupling beams, regardless of the type of the prototype exterior walls.

Preliminary Design Analysis of Low Speed Interior Permanent Magnet Machine with Distributed and Concentrated Windings

  • Ahsanullah, Kazi;Dutta, Rukmi;Rahman, M.F.
    • Journal of international Conference on Electrical Machines and Systems
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    • v.3 no.2
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    • pp.139-147
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    • 2014
  • The paper presents a systematic comparison of four topologies of the interior permanent magnet machine (IPMM) designed for low speed applications. This comparative study investigates the suitability of the concentrated winding and distributed winding in the stator and the flat-shaped or V-shaped magnets in the rotor poles. The paper also studies the inductance characteristics of the designs using finite element analysis. Various steps taken to minimize the cogging torque and torque ripple in the studied machines were also discussed in details.

Vibration Control of Beam using Distributed PVDF Sensor and PZT Actuator (분포형 압전필름 감지기와 압전세라믹 작동기를 이용한 보의 진동 제어)

  • 유정규;박근영;김승조
    • Journal of KSNVE
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    • v.7 no.6
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    • pp.967-974
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    • 1997
  • Distributed piezoeletric sensor and actuator have been designed for efficient vibration control of a cantilevered beam. Both PZT and PVDF have been used in this study, the former as an actuator and the latter as a sensor for the integrated structure. We have optimized the position and the size of the PZT actuator and the electrode shape of the PVDF sensor. Finite element method is used to model the structure and the optimized actuators, we have designed the active electrode width of the PVDF sensor along the span of the beam. Actuator design is based on the criterion of minimizing the system energy in the control modes under a given initial condition. Model control forces for the residual (uncontrolled) modes have been minimized during the sensor design to minimize the observation spill-over. Genetic algorithm and sequential quadratic programming technique have been utilized as an optimization scheme. Discrete LQG control law has been applied to the integrated structure for real time vibration control. Performance of the sensor, the actuator, and the integrated smart structure has been demonstrated by experiments.

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Effect of an Intermediate Support on the Stability of Elastic Material Subjected to Dry Friction Force (건성마찰력을 받는 탄성재료의 안정성에 미치는 중간 지지의 효과)

  • 류시웅;장탁순
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.8
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    • pp.129-135
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    • 2004
  • This paper discussed on the effect of an intermediate support on the stability of elastic material subjected to dry friction force. It is assumed in this paper that the dry frictional force between a tool stand and an elastic material can be modeled as a distributed follower force. The elastic material on the friction material is modeled for simplicity into an elastic beam on Winkler-type elastic foundation. The stability of beams on the elastic foundation subjected to distributed follower force is formulated by using finite element method to have a standard eigenvalue problem. The first two eigen-frequencies are obtained to investigate the dynamics of the beam. The eigen-frequencies yield the stability bound and the corresponding unstable mode. The considered beams lose its stability by flutter or divergence, depending on the location of intermediate support.

Comparison of Concentrated and Distributed Winding in an IPMSM for Vehicle Traction (차량 견인용 IPMSM의 집중권과 분포권 비교)

  • Oh, Se-Young;Im, Jong-Bin;Ham, Sang-Hwan;Jo, Su-Yeon;Yu, Gwang-Hyeon;Lee, Ho-Yong;Lee, Ju
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.842-843
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    • 2011
  • Winding methods of the interior permanent magnet synchronous motor for vehicle traction have two kinds. They are concentrated winding and distributed winding. They have merits and demerits and influence motor performance. Therefore, this paper present designs that concentrated winding and distributed winding motor what they have same capacity. And each motor characteristic was analyzed by finite element analysis.

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Dynamic Stability and Vibration of a Drum Brake Shoe under a Distributed Frictional Force (분포 마찰력을 받는 드럼 브레이크-슈의 동적안정성과 진동)

  • Ryu, Bong-Jo;Ryu, Si-Ung;Yoshihiko Sugiyama;Oh, Boo-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.207-212
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    • 2001
  • In this paper, dynamic stability and vibration characteristics of a flexible shoe in drum brake systems are investigated. The frictional force between the drum and the shoe is assumed as a distributed frictional force, while the shoe is modeled as an elastic beam supported by two translational springs at both ends and elastic foundations. Governing equations of motion are derived by energy expressions, and numerical results are calculated by finite element method. Through the numerical simulation, critical distributed frictional forces are calculated by changing the stiffness of two translational springs and elastic foundation parameters. It is also shown that the beam loses its stability by flutter and divergence depending on the stiffness of elastic supports and elastic foundation parameters. Finally, the time responses of the beam corresponding to their instability types are demonstrated.

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Quasi-Distributed Water Detection Sensor Based On a V-Grooved Single-Mode Optical Fiber Covered with Water-Soluble Index-Matched Medium

  • Kim, Dae Hyun;Kim, Kwang Taek
    • Journal of Sensor Science and Technology
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    • v.24 no.1
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    • pp.1-5
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    • 2015
  • The V-grooved single-mode fiber in which a surface part of the core was removed was investigated as a quasi-distributed water detection sensor. In the normal state, the V-grooved region is filled and covered with a specific RI (Refractive Index)-matched medium, and the sensor experiences minimal optical loss. As water invades the V-grooved region, the material is dissolved and removed, and a considerable optical loss occurs owing to the large RI difference between the fiber core and water. The experimental results showed the feasibility of the device as a sensor element of the quasi-distributed water detection sensor system based on general optical time domain reflectometry (OTDR).

The Effect of an Internal Damping on the Stability of Machine Tool Engineers Subjected to Dry Friction Force (내부감쇠가 건성마찰력을 받는 공작기계의 안정성에 미치는 효과)

  • 고준빈
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.2
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    • pp.112-119
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    • 2004
  • This paper discussed on the effect of an internal damping on the stability of an elastic material subjected to dry friction force. Dry friction forces act tangentially at the contact surface between a moving belt and elastic material. The elastic material on a belt moving is modeled for simplicity into a cantilevered beam subjected to distributed follower force. In the analysis, the discretized equations derived according to finite element method are used. The impulse response of the beam are studied by the mode superposition method to observe the growth rate of the motion. It is found that the internal damping in cantilevered beam subjected to distributed follower force may act destabilizing.

Lumped Element 3-dB $180^{\circ}$ Hybrid With the Impedances Asymmetrically Terminated (비대칭성 종단임피던스를 가진 집중소자 3-dB $180^{\circ}$결합기)

  • 안희란;장익수;윤상원
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.6
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    • pp.18-25
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    • 1994
  • If a 4-port network is terminated by arbitrary impedances, there are great advantageges in composing systems with it. The distributed 3-dB $O^{\circ}$/180$^{\circ}$ hybrid with the impedances asymmetrically terminated is presented. In the band of UHF and VHF. on the basis of it , the new design method of small sized- hybrid using both lumped and distributed elements is also presented and analyzed At the center frequency of 900MHz. 3-dB $O^{\circ}$/180$^{\circ}$hybrid on the RT/Duroid substrate of ${\varepsilon}_{r}$=2.2, h=0.76mm is design and tested. Agreements are obtained between measured and theoretical results and at the same time the occupied area of it is reduced more than 70% compared with only distributed-type circuits.

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Effect of viscous Damping on the Stability of Beam Resting on an Elastic Foundation Subjected to Dry friction force (점성감쇠가 건성마찰력을 받는 탄성지지 보의 안정성에 미치는 효과)

  • 장탁순;고준빈;류시웅
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.11
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    • pp.179-185
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    • 2004
  • The effect of viscous damping on stability of beam resting on an elastic foundation subjected to a dry friction force is analytically studied. The beam resting on an elastic foundation subjected to dry friction force is modeled for simplicity into a beam resting on Kelvin-Voigt type foundation subjected to distributed follower load. In particular, the effects of four boundary conditions (clamped-free, clamped-pinned, pinned-pinned, clamped-clamped) on the system stability are considered. The critical value and instability type of columns on the elastic foundation subjected to a distributed follower load is investigated by means of finite element method for four boundary conditions. The elastic foundation modulus, viscous damping coefficient and boundary conditions affect greatly both the instability type and critical load. Also, the increase of damping coefficient raises the critical flutter load (stabilizing effect) but reduces the critical divergence load (destabilizing effect).