• Title/Summary/Keyword: large displacement analysis

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Analysis of Strength and Displacement of Jig Body in Index Machine (Index Machine의 Jig Body 강도 및 변위해석)

  • 한근조;오세욱;김광영;안성찬;전형용
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.3
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    • pp.24-30
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    • 1998
  • Strength and displacement of jig body in index machine utilized for multiprocess machining such as drilling, boring and tapping, etc, at the same time were analyzed by the use of finite element analysis soft ware ANSYS 5.2A. The whole geometry was constructed by 4048 elements and 7016 nodes employing 8 node brick element. The analyses were carried out on five loading cases combining vertical and horizontal machining to simulate the case occurring large displacement and the one occurring small displacement one and provided following conclusions. (1) Jig body had sufficient strength because its safety factor was 6.95 even in the most severe loading case. (2) The largest displacement in Z direction was 549 m and that in radial direction was 43.7 m. (3) In order to reduce the displacement, vertical machining rather than horizontal or two or three processes should be adopted in the same station. (4) Alternate change of horizontal machining direction at consecutive stations can reduce the displace ment. (5) The dimension of the slider should be increased to reduce the displacement by the tolerance in the sliding part. (6) A bypass idle piston head needs to be installed to give a counterpart supporting load from opposite direction for a single horizontal machining case.

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Large displacement analysis of inelastic frame structures by convected material frame approach

  • Chiou, Yaw-Jeng;Wang, Yeon-Kang;Hsiao, Pang-An;Chen, Yi-Lung
    • Structural Engineering and Mechanics
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    • v.13 no.2
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    • pp.135-154
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    • 2002
  • This paper presents the convected material frame approach to study the nonlinear behavior of inelastic frame structures. The convected material frame approach is a modification of the co-rotational approximation by incorporating an adaptive convected material frame in the basic definition of the displacement vector and strain tensor. In the formulation, each discrete element is associated with a local coordinate system that rotates and translates with the element. For each load increment, the corresponding strain-displacement and nodal force-stress relationships are defined in the updated local coordinates, and based on the updated element geometry. The rigid body motion and deformation displacements are decoupled for each increment. This modified approach incorporates the geometrical nonlinearities through the continuous updating of the material frame geometry. A generalized nonlinear function is used to derive the inelastic constitutive relation and the kinematic hardening is considered. The equation of motion is integrated by an explicit procedure and it involves only vector assemblage and vector storage in the analysis by assuming a lumped mass matrix of diagonal form. Several numerical examples are demonstrated in close agreement with the solutions obtained by the ANSYS code. Numerical studies show that the proposed approach is capable of investigating large deflection of inelastic planar structures and providing an excellent numerical performance.

Design of VCM(Voice Coil Motor) for improvement in resolution and driving in a large displacement (분해능 향상 및 대구동 변위를 위한 보이스코일 모터의 설계)

  • You, Y.M.;Cho, J.H.;Kwon, B.I.
    • Proceedings of the KIEE Conference
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    • 2003.04a
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    • pp.137-139
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    • 2003
  • In this paper, a design of VCM(Voice Coil Motor) for the measurement system of nano-level force and displacement was proposed and developed. This paper present the VCM shape for improvement of position resolution and guarantee of a large displacement. And then the finite element analysis method(FEM) utilized to produce linear driving thrust and satisfy required thrust of the system. The result shows the applicable possibility of the proposed VCM as a study for nano-level measurement system.

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Load-Displacement Characteristics Study of Barrette Pile by Bi-directional Loading Test (양방향재하시험을 통한 바렛말뚝의 하중-침하특성 연구)

  • Lim, Dae-Sung;Park, Seong-Wan;Lee, Sang-Rae
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.754-759
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    • 2008
  • Recently, the construction of buildings and large bridges has been increasing rapidly causing foundation structure growing larger then before, especially in the use of large size cast-in-place piles. Barrette Pile will usually be used at the site where diaphragm wall is the retaining wall to save time and cost in mobilization of equipments. This study uses bi-directional loading test data obtained from two different sites to observe the bearing capacity and displacement characteristics of barrette pile. Numerical analysis of the test is done by using commercial 3D computer program and the interface effect and capacity of the pile as well as displacement characteristics of the pile is verified.

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Study on the Effective Stiffness of Base Isolation System for Reducing Acceleration and Displacement Responses

  • Kim, Young-Sang
    • Nuclear Engineering and Technology
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    • v.31 no.6
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    • pp.586-594
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    • 1999
  • To limit both the large displacement and acceleration response of the structure efficiently, the relationships between acceleration and displacement responses of the structure under several earthquakes are investigated for various horizontal stiffness of the base isolation system to determine the effective stiffness of the base isolation system in this paper. An example structure is a five-storey steel frame building as the primary structure and the secondary structures are assumed to be located on the fifth floor of the primary structure. Input motions used in the structural analysis are El Centre 1940, Taft 1952, Mexico 1985, San Fernando 1971 Pacoima Dam, and artificially generated earthquakes. The relationships of the absolute peak acceleration and the displacement at the top of the structure are calculated for various natural periods of base isolators under various earthquakes. The peak acceleration response of the fifth floor in the base isolated structure is significantly reduced by a factor of 2.1 through 6.25. Also, the relative displacement response of the floor to the base of the superstructure is very small. The results of this study can be utilized to determine the effective stiffness of the base isolation system.

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A Study on the Correlation Analysis of the Present Status of Positive Displacement Pumps Installed in Ships

  • Lee, Sang-Il;Kim, You-Taek
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.3
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    • pp.421-429
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    • 2008
  • Various kinds of ship are operated to transport cargo or passengers at sea in the world. Most of the important auxiliary machineries installed in those ships are fluid machineries such as pumps, compressors, and fans. A large percentage of fluid machinery is pumps which are classified turbo and positive displacement pumps. This paper analyzes only positive displacement pumps. This thesis has two aims: (a) to analyze the present status of pumps installed in merchant and training ships and (b) to find the correlation among sea going pump kW, port pump kW, total pump kW, GE kW, ME MCR, number of pumps, ME kgf, pump kgf. Based on ship's type, this paper seeks to find special characteristics as a result of analyzing head, flow rate, and kW. Moreover this paper analyzes and compares number of pumps, pump kW/ME MCR, pump kW/GE kW under the conditions of seagoing and berthing according to ship's type.

Behavior Due to Construction Step in Steel Deck Bridge by Large Block Construction Method (대블록시공법에 따른 강상판교의 시공단계별 거동)

  • Lee, Seong-Haeng;Kim, Kyoung-Nam;Hahm, Hyung-Gil;Jung, Kyoung-Sup
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.2
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    • pp.97-105
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    • 2010
  • The displacements of steel deck bridge due to construction step are measured, and three dimensional analysis with full modeling is carried out to compare with the measured results. Three dimensional structural analyses considering construction step by large block construction method are accomplished with verified model. The conclusions are as follows. 1. Comparing the data of grid analysis with the result of 3D full modeling in steel deck bridge, the design method using grid analysis has a limit for describing the displacements of curved bridge. The analysis of 3D full modeling has been proved as more accurate method. The differentiation of results in two methods is about 10%~20%. 2. It is verified that the maximum displacement of during construction is 1.7 times larger than the displacement of final construction. 3. The bridge behavior considering the construction step is somewhat different from that of final stage in whole structure and the displacement and stress during construction is larger than that of final construction. Therefore, it needs the reasonable structural design considering the construction step to get economical efficiency and a high competitive construction.

Sensitivity Analysis on Rockfill Material Parameters Influencing Crest Displacement of Concrete-Faced Rockfill Dam (콘크리트 표면차수벽형 석괴댐 정상부 변위에 영향을 미치는 입력물성에 대한 민감도분석)

  • Ha, Ik-Soo;Seo, Min-Woo;Shin, Dong-Hoon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.846-853
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    • 2006
  • In this study, quantitative sensitivity analysis on rockfill material influencing the dam crest displacement of Concrete-Faced Rockfill Dam(CFRD) was carried out. The purpose of this study is to indicate the most important input parameter and to show the quantitative variation of displacement at the crest of CFR type dam with this input parameter. The rockfill material properties for parametric study were obtained from the results of large scale triaxial tests on 34 rockfill materials in the 22 different sites. From the statistical analysis on these data, some statistical characteristics of rockfill material properties such as property range, distribution characteristics, and correlation between the properties were investigated. based on these characteristics, 27 property combinations were constituted by Latin Hypercube sampling method. Dam crest displacements after construction, impounding, and earthquake loading were evaluated by static and dynamic numerical analysis on each combination. From the sensitivity analysis, it was found that the crest displacement of CFR type dam was absolutely affected by the shear modulus of rockfill material and the effect of friction angle of it was negligible. This relative difference of sensitivity was more outstanding in case of crest settlement than in case of crest horizontal displacement. Also, it was found that the settlement and horizontal displacement of dam crest logarithmically decreased as the shear modulus increased and the difference between the maximum value and the minimum vale amounted to about 9.5 times in case of settlement and about 10 times in case of horizontal displacement.

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Development of Continuous Ground Deformation Monitoring System using Sentinel Satellite in the Korea (Sentinel 위성기반 한반도 연속 지반변화 관측체계 개발)

  • Yu, Jung Hum;Yun, Hye-Won
    • Korean Journal of Remote Sensing
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    • v.35 no.5_2
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    • pp.773-779
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    • 2019
  • We developed the automatic ground deformation monitoring system using Sentinel-1 satellites which is operating by European Space Agency (ESA) for the Korea Peninsula's ground disaster monitoring. Ground deformation occurring over a long-term period are difficult to monitoring because it occurred in a wide area and required a large amount of satellite data for analysis. With the development of satellites, the methods to regularly observe large areas has been developed. These accumulated satellite data are used for time series ground displacement analysis. The National Disaster Management Research Institute (NDMI) established an automation system for all processes ranging from acquiring satellite observation data to analyzing ground displacement and expressing them. Based on the system developed in this research, ground displacement data on the Korean Peninsula can be updated periodically. In the future, more diverse ground displacement information could be provided if automated small regional analysis systems, multi-channel analysis method, and 3D analysis system techniques are developed with the existing system.