• Title/Summary/Keyword: interface structure

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Model Updating of a Car Body Structure Using a Generalized Free-Interface Mode Sensitivity Method (일반화 자유경계 모드 감도법을 이용한 차체구조물의 모델개선)

  • Jang, Gyeong-Jin;Park, Yeong-Pil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.5 s.176
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    • pp.1133-1145
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    • 2000
  • It is necessary to develop an efficient analysis method to identify the dynamic characteristics of a large mechanical structure and update its finite element model. That is because these processes need the huge computation of a large structure and iterative estimation due to the use of the first- order sensitivity. To efficiently carry out these processes, a new method, called the generalized free-interface mode sensitivity method, has been proposed in the authors' preceeding paper. This method is based on substructuring approach such as a free-interface method and a generalized synthesis algorithm. In this paper, the proposed method is applied to the model updating of a car body structure to verify its accuracy and reliability for a large mechanical structure.

Nonlinear Earthquake Response Analysis of 2-D Underground Structures with Soil-Structure Interaction Including Separation and Sliding at Interface (지반-구조물 상호작용계의 경계면에서 미끄러짐과 분리현상을 고려한 이차원 지하구조물의 비선형 지진응답해석)

  • 최준성;이종세;김재민
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.04a
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    • pp.174-181
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    • 2002
  • The paper presents an effective analytical method for SSI systems which can have separation or sliding at the soil-structure interface. The method is based on a hybrid approach which combines a linear SSI code KIESSI-2D in frequency domain with a commercial finite element package ANSYS to obtain nonlinear dynamic responses in time domain. The method is applied to a 2-D underground box structure which experiences separation and sliding at the soil-structure interface. Material nonlinearity of the concrete structure is also included in the analysis. Effects of the interface conditions are examined and some critical factors affecting the seismic performance of underground structures are identified.

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Structural Study of Tetragonal-Ni1-xPdxSi/Si (001) Using Density Functional Theory (DFT) (Density Functional Theory (DFT)를 이용한 Tetragonal-Ni1-xPdxSi/Si (001)의 구조 연구)

  • Kim, Dae-Hee;Seo, Hwa-Il;Kim, Yeong-Cheol
    • Korean Journal of Materials Research
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    • v.18 no.9
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    • pp.482-485
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    • 2008
  • Tetragonal-$Ni_{1-x}Pd_x$Si/Si (001) structure was studied by using density functional theory (DFT). An epitaxial interface between $2{\times}2{\times}4$ (001) tetragonal-NiSi supercell and $1{\times}1{\times}2$ (001) Si supercell was first constructed by adjusting the lattice parameters of B2-NiSi structure to match those of the Si structure. We chose Ni atoms as a terminating layer of the B2-NiSi; the equilibrium gap between the tetragonal-NiSi and Si was calculated to be 1.1 ${\AA}$. The Ni atoms in the structure moved away from the original positions along the z-direction in a systematic way during the energy minimization. Two different Ni sites were identified at the interface and the bulk, respectively. The two Ni sites at the interface have 6 and 7 coordination numbers. The Ni sites with coordination number 6 at the interface were located farther away from the interface, and were more favorable for Pd substitution.

Electronic Structure of Organic/organic Interface Depending on Heteroepitaxial Growth Using Templating Layer

  • Lim, Hee Seon;Kim, Sehun;Kim, Jeong Won
    • Applied Science and Convergence Technology
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    • v.23 no.6
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    • pp.351-356
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    • 2014
  • The electronic structure at organic-organic interface gives essential information on device performance such as charge transport and mobility. Especially, the molecular orientation of organic material can affect the electronic structure at interface and ultimately the device performance in organic photovoltaics. The molecular orientation is examined by the change in ionization potential (IP) for metal phthalocyanines (MPc, M=Zn, Cu)/fullerene ($C_{60}$) interfaces on ITO by adding the CuI templating layer through ultraviolet photoelectron spectroscopy measurement. On CuPc/$C_{60}$ bilayer, the addition of CuI templating layer represents the noticeable change in IP, while it hardly affects the electronic structure of ZnPc/$C_{60}$ bilayer. The CuPc molecules on CuI represent relatively lying down orientation with intermolecular ${\pi}-{\pi}$ overlap being aligned in vertical direction. Consequently, in organic photovoltaics consisting of CuPc and $C_{60}$ as donor and acceptor, respectively, the carrier transport along the direction is enhanced by the insertion of CuI templaing layer. In addition, optical absorption in CuPc molecules is increased due to aligned transition matrix elements. Overall the lying down orientation of CuPc on CuI will improve photovoltaic efficiency.

The Behavior of Adjacent Structures in Urban Excavation Considering Soil-Structure Interaction (지반굴착시 지반/구조물 상호작용이 고려된 구조물의 거동 평가 연구)

  • Yang, Sung-Woo;Kim, Chan-Kuk;Hwang, Eui-Seok;Kim, Zu-Cheol;Kim, Hak-Moon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.1024-1031
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    • 2006
  • In this study using the finite different programs, FLAC2D to define affection of the soil-structure interface in evaluating the behavior of adjacent structures according to excavation, and tried to compare each the results of different 46 cases which were various condition of stories, length and locations from the excavation site. In the result of the numerical analysis, the affection of the interface was affected by the building stories, locations from the excavation site and shape ratio(length/height). Therefore, in the considering soil-structure interaction in the damage assessment and the behavior of the adjacent structures when excavation, is important in more accurate evaluation of the movement of structure. Also, the interface modification factor were proposed which can consider the interface.

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The Band Structure of GaAs/(Al,Ga)As Superlattice with Interface Grading (계면경사가 있는 GaAs/(Al, Ga)As 초격자의 밴드구조)

  • 김장래;김충원;한백형
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.3
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    • pp.287-293
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    • 1988
  • This paper calculates the band structure of the GaAs/(Al,Ga) As semiconductor superlttice with the interface3 grading, in consideration of different effective masses in each region. Including the effective masses, superlattice period, well and barrier widths, and the interface, the dispersion relation is derived, and the effects that the above parameters affect the subband (or miniband) structure of the superlattice and effective energy gap are investigated. It is particularly found that this case(ma<>mb<>mc) is significantly different from the same effective mass case(ma<>mb<>mc).

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An experimental study on shear mechanical properties of clay-concrete interface with different roughness of contact surface

  • Yang, Wendong;Wang, Ling;Guo, Jingjing;Chen, Xuguang
    • Geomechanics and Engineering
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    • v.23 no.1
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    • pp.39-50
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    • 2020
  • In order to understand the shear mechanical properties of the interface between clay and structure and better serve the practical engineering projects, it is critical to conduct shear tests on the clay-structure interface. In this work, the direct shear test of clay-concrete slab with different joint roughness coefficient (JRC) of the interface and different normal stress is performed in the laboratory. Our experimental results show that (1) shear strength of the interface between clay and structure is greatly affected by the change of normal stress under the same condition of JRC and shear stress of the interface gradually increases with increasing normal stress; (2) there is a critical value JRCcr in the roughness coefficient of the interface; (3) the relationship between shear strength and normal stress can be described by the Mohr Coulomb failure criterion, and the cohesion and friction angle of the interface under different roughness conditions can be calculated accordingly. We find that there also exists a critical value JRCcr for cohesion and the cohesion of the interface increases first and then decreases as JRC increases. Moreover, the friction angle of the interface fluctuates with the change of JRC and it is always smaller than the internal friction angle of clay used in this experiment; (4) the failure type of the interface of the clay-concrete slab is type I sliding failure and does not change with varying JRC when the normal stress is small enough. When the normal stress increases to a certain extent, the failure type of the interface will gradually change from shear failure to type II sliding failure with the increment of JRC.

Interface Design of Virtual Modeling Dataand Nonlinear Analysis Program (Virtual Modeling Data와 비선형 해석 프로그램의 Interface 설계)

  • Park, Jae-Guen;Lee, Heon-Min;Jo, Sung-Hoon;Lee, Kwang-Myong;Shin, Hyun-Mock
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2008.04a
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    • pp.100-103
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    • 2008
  • Recently Development of construction system that subjective operators share and control information efficiently based on the three-dimensional space and design information throughout life cycle of construction project is progressing dynamically. In case of civil structures which are infrastructure, Demand for structure of complex system which has multi-functions such as super and smart bridges and express rails is increasing and system development which computerizes and integrates process of structure design is in need. For that, research about link way between three dimensional modeling data and structure analysis programs should be preceded. In this research, therefore, research about interface design between three dimensional virtual modeling data to automate efficient civil-structure-design and nonlinear finite element analysis program which is made up of reinforced concrete material model that express material's character clearly.

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Thermomechanical Analysis of Functionally Gradient Al-$SiC_{p}$ Composite for Electronic Packaging (전자패키지용 경사조성 Al-$SiC_{p}$ 복합재료의 열 . 기계적 변형특성 해석)

  • 송대현;최낙봉;김애정;조경목;박익민
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.04a
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    • pp.175-183
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    • 2000
  • The internal residual stresses within the multilayered structure with shan interface induced by the difference in thermal expansion coefficient between the materials of adjacent layers often provide the source of failure such as delamination of interfaces and etc. Recent development of the multilayered structure with functionally graded interface would be the solution to prevent this kind of failure. However a systematic thermo-mechanical analysis is needed fur the customized structural design of multilayered structure. In this study, theoretical model for the thermo-mechanical analysis is developed for multilayered structures of the Al-$SiC_p$ functionally graded composite for electronic packaging. The evolution of curvature and internal stresses in response to temperature variations is presented for the different combinations of geometry. The resultant analytical solutions are used for the optimal design of the multilayered structures with functionally graded interface as well as with sharp interface.

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Damage Monitoring in Foundation-Structure Interface of Harbor Caisson Using Vibration-based Autoregressive Model (진동기반 자기회귀모델을 통한 항만케이슨 지반-구조 경계부의 손상 모니터링)

  • Lee, So-Ra;Lee, So-Young;Kim, Jeong-Tae;Park, Woo-Sun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.23 no.1
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    • pp.18-25
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    • 2011
  • This study presents the damage monitoring method in foundation-structure interface of harbor caisson using vibration-based autoregressive (AR) model. In order to achieve the objective, the following approaches are implemented. Firstly, vibration-based AR model is selected to monitor the damage in foundation-structure interface of caisson structure. Secondly, finite element analysis on a caisson structure model is implemented to evaluate the vibration-based damage monitoring method. Finally, vibration test on a caisson structure model is performed to evaluate applicability of vibration-based AR model method for foundation-structure interface of caisson structure.