• Title/Summary/Keyword: Load transfer analysis

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THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF THE EFFECT OF CORTICAL ENGAGEMENT ON IMPLANT LOAD TRANSFER IN POSTERIOR MANDIBLE (하악구치부 피질골 engagement가 임플란트 하중전달에 미치는 영향에 관한 3차원 유한요소법적 응력분석)

  • Jeong, Chang-Mo
    • The Journal of Korean Academy of Prosthodontics
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    • v.37 no.5
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    • pp.607-619
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    • 1999
  • Cortical support is an important factor, as the engagement of the fixture in strong compact bone offers an increased load-carrying capacity and initial stability. Because of the poor bone quality in the posterior mandible and other anatomic considerations, it has been suggested that implant fixtures be placed in these locations with apical engagement of the lingual cortical plate for so-called bicortication. The purpose of this investigation was to determine the effect of cortical engagements and in addition polyoxymethylene(POM) intramobile connector(IMC) of IMZ implant on implant load transfer in edentulous posterior segment of mandible, using three-dimensional (3D) finite element analysis models composed of cortical and trabecular bone involving single implant. Variables such as (1) the crestal peri-implant defect, (2) the apical engagement of lingual cortical plate, (3) the occlusal contact position (a vertical load at central fossa or buccal cusp tip), and (4) POM IMC were investigated. Stress patterns were compared and interfacial stresses along the bone-implant interface were monitored specially. Within the scope of this study, the following observations were made. 1) Offset load and angulation of fixture led to increase the local interfacial stresses. 2) Stresses were concentrated toward the cortical bones, but the crestal peri-implant defect increased the interfacial stresses in trabecular bone. 3) For the model with bicortication, it was noticed that the crestal cortical bone provided more resistance to the bending moment and the lingual cortical plate provided more support for the vertical load. But Angulation problem of the fixture from the lingual cortical engagement caused the local interfacial stress concentrations. 4) It was not clear that POM IMC had the effect on stress distribution under the present experimental conditions, especially for the cases of crestal peri-implant defect.

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Performance monitoring of offshore PHC pipe pile using BOFDA-based distributed fiber optic sensing system

  • Zheng, Xing;Shi, Bin;Zhu, Hong-Hu;Zhang, Cheng-Cheng;Wang, Xing;Sun, Meng-Ya
    • Geomechanics and Engineering
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    • v.24 no.4
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    • pp.337-348
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    • 2021
  • Brillouin Optical Frequency Domain Analysis (BOFDA) is a distributed fiber optic sensing (DFOS) technique that has unique advantages for performance monitoring of piles. However, the complicated production process and harsh operating environment of offshore PHC pipe piles make it difficult to apply this method to pile load testing. In this study, sensing cables were successfully pre-installed into an offshore PHC pipe pile directly for the first time and the BOFDA technique was used for in-situ monitoring of the pile under axial load. High-resolution strain and internal force distributions along the pile were obtained by the BOFDA sensing system. A finite element analysis incorporating the Degradation and Hardening Hyperbolic Model (DHHM) was carried out to evaluate and predict the performance of the pile, which provides an improved insight into the offshore pile-soil interaction mechanism.

Performance Analysis of Contactless Electrical Power Transfer for Maglev

  • Hasanzadeh, S.;Vaez-Zadeh, S.
    • Journal of Magnetics
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    • v.17 no.2
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    • pp.115-123
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    • 2012
  • Contactless electrical power transfer through an air gap is a revived technology for supplying energy to many movable applications including Maglev. In this paper, magnetic equivalent circuits and analytical models of contactless electrical power transfer systems are developed and evaluated through experiment. Overall coupling coefficient and overall efficiency are introduced as means for evaluating the systems' performance. Compensating capacitors in primary and secondary sides of the systems improve the overall coupling coefficient and overall efficiency. Using the analytical models, the effects of different parameters and variables such as air gap and load current are analyzed to give a high coupling coefficient and an improved efficiency of power transfer for different compensation structures.

Model Tests for Vertical Loads Acting on Embankment Piles (성토지지말뚝에 작용하는 연직하중에 대한 모형실험)

  • 홍원표;강승인
    • Journal of the Korean Geotechnical Society
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    • v.16 no.4
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    • pp.171-181
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    • 2000
  • A series of model tests were performed both to investigate the load transfer by soil acrching in fills above embankment pils and to verify of the theoretical analysis. In the model tests, the piles were installed in a row below the embankment and the cap beams were placed on the pile heads perpendicular to the longitudinal axias of the embankment. The space between pile cap beams and the embankment height was focused as the major factors affecting the load transfer in embankment fill. When the embankment fill was higher than the minimum required height, which was about 33% higher than the radius of the soil arch proposed by theoretical discussion in the previous study, not only the soil arching could be developed completely but also the experimental results showed good agreement with theoretical predictions. The portion of the embankment load carried by model pile cap beams decreased with increment of the space between pile cap beams, while it increased with increment of the embankment height. Therefore, to maximize the effect of embankment load transfer by piles on design, the interval ratio of pile cap beams should be decreased under considerably high embankments by reducing the space between cap beams and/or enlarging the width of pile cap beams.

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A study on an efficient prediction of welding deformation for T-joint laser welding of sandwich panel Part II : Proposal of a method to use shell element model

  • Kim, Jae Woong;Jang, Beom Seon;Kang, Sung Wook
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.6 no.2
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    • pp.245-256
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    • 2014
  • I-core sandwich panel that has been used more widely is assembled using high power $CO_2$ laser welding. Kim et al. (2013) proposed a circular cone type heat source model for the T-joint laser welding between face plate and core. It can cover the negative defocus which is commonly adopted in T-joint laser welding to provide deeper penetration. In part I, a volumetric heat source model is proposed and it is verified thorough a comparison of melting zone on the cross section with experiment results. The proposed model can be used for heat transfer analysis and thermal elasto-plastic analysis to predict welding deformation that occurs during laser welding. In terms of computational time, since the thermal elasto-plastic analysis using 3D solid elements is quite time consuming, shell element model with multi-layers have been employed instead. However, the conventional layered approach is not appropriate for the application of heat load at T-Joint. This paper, Part II, suggests a new method to arrange different number of layers for face plate and core in order to impose heat load only to the face plate.

Fire Behavior of Reinforced Concrete Filled Square Steel Tube Columns Under Constant Axial Loads

  • Jeeyoung Lee;Seulgi Han;Jinwon Shin;Inrak Choi;Sungmo Choi
    • International Journal of High-Rise Buildings
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    • v.13 no.1
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    • pp.85-95
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    • 2024
  • A composite member made of concrete-filled steel tubes (CFT columns) has been recognized for its fire resistance due to the thermal mass effect of concrete inside the steel tube, as shown in various studies. In this study, the fire resistance performance of reinforced CFT columns under constant axial load was evaluated using finite element analysis with ABAQUS. For this purpose, the variables including cross-section size, steel tube thickness, and concrete cover thickness were set, and the temperature distribution in the column cross-section exposed to a standard fire was investigated using heat transfer analysis. Ultimately, a P-M interaction curve was obtained by evaluating the overall residual strength of columns, and the fire resistance time was determined by evaluating axial displacement-time responses due to the reduction in load capacity during fire through stress analysis.

Bidirectional Magnetic Wireless Communication System under Inductive Power Transfer capable of Amplitude-Shift Keying(ASK) Modulation Control (자기유도 무선전력전송시 진폭편이변조 제어가 가능한 양방향 자기장 무선통신 시스템)

  • Choi, Byeung-Guk;Lee, Eun-Soo;Rim, Chun-Taek
    • The Transactions of the Korean Institute of Power Electronics
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    • v.21 no.3
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    • pp.275-281
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    • 2016
  • A novel bidirectional magnetic wireless communication system is proposed in this study. This system provides the communication capability between the source and load sides by high-frequency signal while wireless power is transferred. Contrary to the conventional wireless communication systems using complex IC circuit and active components, the proposed system is simply composed of passive components. It is practical and beneficial for environmental robustness, cost effectiveness, and simple implementation. The detailed static analysis of the proposed system for power and communication lines is established. The proposed system is experimentally verified, and results show that a 0.1 voltage gain for communication line is obtained while a 2.0 voltage gain for the power line is achieved. The proposed system is adequate for practical applications as it allows the inductive power transfer system to wirelessly and easily communicate between the source and load sides.

Prediction on Ultimate Vertical and Horizontal Bearing Capacity of Steel Pipe Piles by Means of PAR (PAR에 의한 강관 말뚝의 극한 수직 및 수평 지지력 예측)

  • 최용규
    • Geotechnical Engineering
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    • v.13 no.4
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    • pp.13-24
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    • 1997
  • A predicting method for ultimate vertical and horizontal bearing capacity by means of PAR(Pile Analysis Routines) was suggested. Based on the static pile load test data, case studies by means of PAR were performed. Ultimate pile capacity predicted by PAR was within 15% error range of that determined by stairs pile load tests. Also, the results of static pile load test, statnamic tests and PDA data performed on pipe piles were compared and, by using PAR, ultimate pile capacity was determined. Distributions of atrial pile load could be predicted and load transfer analysis could be done approximately by those distributions.

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Numerical analyses of the force transfer in concrete-filled steel tube columns

  • Starossek, Uwe;Falah, Nabil;Lohning, Thomas
    • Structural Engineering and Mechanics
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    • v.35 no.2
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    • pp.241-256
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    • 2010
  • The interaction between steel tube and concrete core is the key issue for understanding the behavior of concrete-filled steel tube columns (CFTs). This study investigates the force transfer by natural bond or by mechanical shear connectors and the interaction between the steel tube and the concrete core under three types of loading. Two and three-dimensional nonlinear finite element models are developed to study the force transfer between steel tube and concrete core. The nonlinear finite element program ABAQUS is used. Material and geometric nonlinearities of concrete and steel are considered in the analysis. The damage plasticity model provided by ABAQUS is used to simulate the concrete material behavior. Comparisons between the finite element analyses and own experimental results are made to verify the finite element models. A good agreement is observed between the numerical and experimental results. Parametric studies using the numerical models are performed to investigate the effects of diameterto-thickness ratio, uniaxial compressive strength of concrete, length of shear connectors, and the tensile strength of shear connectors.

A Numerical Analysis of Convective Heat Transfer in Air Flow Channels of a Plate Fin-tube Matrix for Heat Pipe Heat Sinks (히트파이프 히트싱크에서 평판 휜-관으로 구성된 공기유동 냉각채널의 대류 열전달 특성에 관한 수치해석)

  • Kim Sung-Hoon;Shin Hyun-Myung;Kim Chul-Ju
    • Journal of Advanced Marine Engineering and Technology
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    • v.29 no.8
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    • pp.862-869
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    • 2005
  • A study on convective cooling characteristics has been done in the channels with heat pipes and associated Plane fins Analysis with FLUENT V5.0 lies its Purpose on the possible enhancement of heat transfer capability between an existing three in-line arrayed heatpipes and an extending four in-line arrayed heatpipes with increasing channel width. Numerical analysis is limited to the laminar flow in an isolated flow channel by employing cyclic boundary conditions for calculation purposes. Friction factors for three and four in-line arrayed heatpipes are compared with experimental results. In addition, temperature behavior at the plate fin for the three in-line arrayed heatpipes is compared with experiment. Friction factors and overall channel heat transfer coefficients (and/or Nusselt numbers) are presented as a function of Reynolds number. An increase of number of heatpipes and channel width reults in a decrease of the friction factor and doesn't not result in an increase of heat transfer performance. However. considering the 25$\%$ increase of heat load accompanies with maximum 8$^{\circ}C$ rise of average temperature of heat pipes, the four in-line array with the increase of channel width of heat pipe heat sink can be considered appropriate.