• Title/Summary/Keyword: complete element

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On the Slipping Phenomenon in Adhesive Complete Contact Problem (응착 완전 접촉 문제에서 접촉면 미끄럼 현상에 관한 고찰)

  • Kim, Hyung-Kyu
    • Tribology and Lubricants
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    • v.36 no.3
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    • pp.147-152
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    • 2020
  • This paper is within the framework of an adhered complete contact problem wherein the contact between a half plane and sharp edged indenter, both of which are elastic in character, is constituted. The eigensolutions of the contact shear and normal stresses, σrq and σq, respectively, are evaluated via asymptotic analysis. The ratio of σrqqq is investigated and compared with the coefficient of friction, μ, of the contact surface to observe the propensity to slip on the contact surface. Interestingly, there exists a region of |σθθ| ≥ |μ|. Thus, slipping can occur, although the problem is solved under the condition of an adhered contact without slipping. Given that a tribological failure potentially occurs at the slipping region, it is important to determine the size of the slipping region. This aspect is also factored in the paper. A simple example of the adhered contact between two elastically dissimilar squares is considered. Finite element analysis is used to evaluate generalized stress intensity factors. Furthermore, it is repeatedly observed that slipping occurs on the contact surface although the size of it is extremely small compared with that of the contacting squares. Therefore, as a contribution to the field of contact mechanics, this problem must be further explained logically.

Role of Alloyed Components on Densification of Mixed and Prealloyed High Speed Steel Powder Compacts (흔합 및 합금고속도강 소결체의 치밀화에 미치는 구성성분의 역할)

  • 임태환
    • Journal of Powder Materials
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    • v.1 no.2
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    • pp.153-158
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    • 1994
  • The effect of the role of alloyed components on the densification of two kind of high speed steel (mixed and prealloyed powder), which were sintered at 1403~ 1573 K for 7.2 ks in vacuum, was investigated. The results obtained were as follows. (1) Without the presence of Vanadium (V), the relative density of sintered compacts (Ds) could not reached the density of 100% regardless of the. elements in the compacts. (2) The addition of V up to 2 mass% did not result In the complete densification when the carbon content was fixed at 2% in the compact. (3) With the fixed amount of V of 7%, Ds decreased with the increase of the carbon content. (4) The addition of mixed fine powder to the prealloyed powder in the range of 20 to 40% provided the complete densification and carbide panicles of 1~2 $\mu\textrm{m}$ through the solid phase sintering. (5) The V element played important role in controlling the complete or incomplete densification of the sintered compacts in the alloyed component because of its formation of stable oxide and carbide as well as the low equilibrium pressure of CO gas.

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Simplified Approach to Repair of Complete Atrioventricular Septal Defect (완전방실중격결손수술의 단순화)

  • 김웅한;김수철;오삼세;정도현;정홍주;김욱성;이창하;정철현;나찬영
    • Journal of Chest Surgery
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    • v.31 no.9
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    • pp.899-902
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    • 1998
  • Recent advances in understanding the anatomy of complete atrioventricular septal defect have led to alternative methods of repairing these defects. Here we report two cases of complete atrioventricular septal defect repair by direct closure of the ventricular element of the defect. Follow-up for average of 3 months suggests that, when direct closure can be performed, the results can be comparable with those of the standard technique. Our initial success with this approach is encouraging; however, longer follow-up and more experiences are required to establish whether it will be broadly applicable.

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Crippling Analysis of Z-Section Composite Stringers (Z-단면 복합재 스트링거의 크리플링 해석)

  • 권진회
    • Composites Research
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    • v.12 no.6
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    • pp.65-73
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    • 1999
  • Crippling stress and failure behavior of Z-section graphite/epoxy composite laminated stringers are investigated by the nonlinear finite element method. Stringers are idealized using 9-node laminated shell element. The complete unloading model is introduced into the finite element method for the progressive failure analysis. A modified Riks method is used to trace the post-failure equilibrium path after local buckling. Finite element results are validated with previous experimental results. The results show that the most important parameter affecting the crippling stress of Z-section stringers is the flange width. In terms of stacking sequence. the highest cripping stress is found at the stringer with $[{\pm}45/0/90]s$ lamination.

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Performance Analysis of Various Forward Solvers in Electrical Impedance Tomography (전기 임피던스 단층촬영 기법에서 여러 정문제 해법들에 대한 성능 비교분석)

  • Kim, Bong Seok;Kim, Kyung Youn
    • Journal of IKEEE
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    • v.19 no.3
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    • pp.407-414
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    • 2015
  • Electrical impedance tomography is an imaging technique to reconstruct the internal conductivity distribution based on applied small currents and measured voltages through an array of electrodes attached on the boundary of a domain of interest. In this paper, an analytical solver with complete electrode model is derived and the analytical voltage data are calculated. Moreover, the voltage data are also computed with existing numerical solvers such as finite element method and boundary element method. The forward solutions using homogeneous and inhomogeneous conditions are compared with phantom experiments through the root mean square errors.

Relation between total degradation of steel concrete bond and degree of corrosion of RC beams experimental and computational studies

  • Maurel, Olivier;Dekoster, Mickael;Buyle-Bodin, Francois
    • Computers and Concrete
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    • v.2 no.1
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    • pp.1-18
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    • 2005
  • This paper presents a study on the effects of localized steel-concrete bond degradation on the flexural behaviour of RC beams. A finite element analysis is undertaken to complete the experimental analysis. The first part deals with an experimental study on beams where bond was removed by using plastic tube at different locations and for various lengths. The flexural behaviour was studied at global scale (load-deflection) and local scale (moment-curvature). The second part, a numerical study using a simplified special finite element (rust element) modelling the rust layer occurring between reinforcement and concrete with corrosion was conducted in order to find the relation between the degree of corrosion and the degradation of the steel-concrete bond. The computed value of the corrosion degree corresponding to the total degradation of bond has been used in a second time to model the tests, in order to evaluate the influence of the loss of bond, the steel cross section reduction, and the combination of both. The results enable to evaluate the influence of the different corrosion effects on the flexural behaviour, according to the length and the location of the corroded zone.

Staged Finite Element Modeling with Coupled Seepage and Stress Analysis

  • Lee, Jae-Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.6
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    • pp.703-714
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    • 2010
  • This paper proposes an approach for staged finite element modeling with coupled seepage and stress analysis. The stage modeling is based on the predefined inter-relationship between the base model and the unit stage models. A unit stage constitutes a complete finite element model, of which the geometries and attributes are subject to changes from stage to stage. The seepage analysis precedes the mechanical stress analysis at every stage. Division of the wet and dry zone and the pore pressures are evaluated from the seepage analysis and used in determining input data for the stress analysis. The results of the stress analysis may also be associated with the pore water pressures. For consolidation analysis, the pore pressure and the displacement variables are mixed in a coupled matrix equation. The time marching solution produces the dissipation of excess pore pressure and variation of stresses with passage of time. For undrained analysis, the excess pore pressures are computed from the stress increment due to loading applied in the unit stage and are used in revising the hydraulic head. The solution results of a unit stage are inherited and accumulated to the subsequent stages through the relationship of the base model and the individual unit stages. Implementation of the proposed approach is outlined on the basis of the core procedures, and numerical examples are presented for demonstration of its application.

A Study on the Principles of Spatial Organization of the Seyeon-jong Garden, Buyong-dong Bogil-do (보길도 부용동 세연정정원의 공간구성 원리에 관한 연구)

  • 최은정;홍광균
    • Journal of the Korean Institute of Landscape Architecture
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    • v.22 no.1
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    • pp.135-148
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    • 1994
  • When we put a construction on the space organization form of Seyeon-jong garden through a consequence of drawing analysis, we were able to certify that a certain space construction principle was applied as following. First, the arrangement and organization of space construction element embodied systematic order y clearing the character of space, and heightening the degree of cognizance with the means of functionability, scale, height, decorationability, an inclination of artificiality and nature, systemetic approchability. Second, the space construction element of Seyeon-jong garden pursued a harmony of human work and nature for creating a various atmosphere and visual quality. Third, Seyeon-jong garden constructed the space by establishing the measurement of human scale that introduced a conception of near, middle, distant view on the visual angle. Forth, Yun go san introduced the natural shape of 'The song of five friends' as a construction element, and represented the symbolism that he had seeked for throught he arrangement method, christening, composing technique of the space construction element for expressing ideal space which is described in 'The four season song of fishermen' spatially at Seyeon-jong garden. As the results of this study, that Yun go san created his own ideal space that he longed for at Seyeon-jong garden with applying fixed design system, and he realized his will that he strived to form a complete whole in perfect harmony.

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The MIN-N family of pure-displacement, triangular, Mindlin plate elements

  • Liu, Y. Jane;Riggs, H.R.
    • Structural Engineering and Mechanics
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    • v.19 no.3
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    • pp.297-320
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    • 2005
  • In recent years the pure displacement formulation for plate elements has not been as popular as other formulations. We revisit the pure displacement formulation for shear-deformable plate elements and propose a family of N-node, displacement-compatible, fully-integrated, pure-displacement, triangular, Mindlin plate elements, MIN-N. The development has been motivated by the relative simplicity of the pure displacement formulation and by the success of the existing 3-node plate element, MIN3. The formulation of MIN3 is generalized to obtain the MIN-N family, which possesses complete, fully compatible kinematic fields, in which the interpolation functions for transverse displacement are one degree higher than those for rotations. General element-level formulas for the thin-limit Kirchhoff constraints are developed. The 6-node, 18 degree-of-freedom element MIN6, with cubic displacement and quadratic rotations, is implemented and tested extensively. Numerical results show that MIN6 exhibits good performance for both static and dynamic analyses in the linear, elastic regime. The results illustrate that the fully-integrated MIN6 element has excellent performance in the thin limit, even for coarse meshes, and that it does not require shear relaxation.

Seismic analysis of dam-foundation-reservoir coupled system using direct coupling method

  • Mandal, Angshuman;Maity, Damodar
    • Coupled systems mechanics
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    • v.8 no.5
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    • pp.393-414
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    • 2019
  • This paper presents seismic analysis of concrete gravity dams considering soil-structure-fluid interaction. Displacement based plane strain finite element formulation is considered for the dam and foundation domain whereas pressure based finite element formulation is considered for the reservoir domain. A direct coupling method has been adopted to obtain the interaction effects among the dam, foundation and reservoir domain to obtain the dynamic responses of the dam. An efficient absorbing boundary condition has been implemented at the truncation surfaces of the foundation and reservoir domains. A parametric study has been carried out considering each domain separately and collectively based on natural frequencies, crest displacement and stress at the neck level of the dam body. The combined frequency of the entire coupled system is very less than that of the each individual sub-system. The crest displacement and neck level stresses of the dam shows prominent enhancement when coupling effect is taken into consideration. These outcomes suggest that a complete coupled analysis is necessary to obtain the actual responses of the concrete gravity dam. The developed methodology can easily be implemented in finite element code for analyzing the coupled problem to obtain the desired responses of the individual subdomains.