• Title/Summary/Keyword: Computational analysis modeling

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Enhanced mass balance Tafel slope model for computer based FEM computation of corrosion rate of steel reinforced concrete coupled with CO2 transport

  • Hussain, Raja Rizwan
    • Computers and Concrete
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    • v.8 no.2
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    • pp.177-192
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    • 2011
  • This research paper aims at computer based modeling of carbonation induced corrosion under extreme conditions and its experimental verification by incorporating enhanced electrochemical and mass balance equations based on thermo-hygro physics with strong coupling of mass transport and equilibrium in micro-pore structure of carbonated concrete for which the previous research data is limited. In this paper the carbonation induced electrochemical corrosion model is developed and coupled with carbon dioxide transport computational model by the use of a concrete durability computer based model DuCOM developed by our research group at concrete laboratory in the University of Tokyo and its reliability is checked in the light of experiment results of carbonation induced corrosion mass loss obtained in this research. The comparison of model analysis and experiment results shows a fair agreement. The carbonation induced corrosion model computation reasonably predicts the quantitative behavior of corrosion rate for normal air dry relative humidity conditions. The computational model developed also shows fair qualitative corrosion rate simulation and analysis for various pH levels and coupled environmental actions of chloride and carbonation. Detailed verification of the model for the quantitative carbonation induced corrosion rate computation under varying relative conditions, different pH levels and combined effects of carbonation and chloride attack remain as scope for future research.

Computational Modeling of Bolt Joint for Machine Tools (공작기계 볼트결합부의 전산모델링)

  • Lee, Jae-Hak;Ha, Tae-Ho;Lee, Chan-Hong
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.10
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    • pp.1070-1077
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    • 2012
  • Virtual machine tools have been magnified recently as manufacturers could estimate performances of machine tools before design and manufacturing of them. However, it requires much time and efforts to make FEM models and predict precision of machine tools well because machine tools are composed of many joints such as bolt joints, LM joints, rotational bearing joints and mounts. Especially, we have studied computational modeling methods of bolt joints to predict precision of machine tools well in this paper. Stiffness and damping coefficients of bolt joints are investigated and generalized with respect to fasten forces through experiments and FEM analysis. Matrix 27 element of ANSYS is used and bolt joints are simplified as square areas with 8 nodes to apply stiffness and damping simultaneously. Additionally, coordinate transformation of matrix 27 for bolt joints is induced to apply to skewed bolt joints of machine tools and evaluate it using FEM analysis.

Multi-body Dynamic Analysis for the Drivetrain System of a Large Wind Turbine Based on GL 2010 (GL 2010 기반 대형 풍력터빈 드라이브트레인 시스템 다물체 동역학 해석기법)

  • Jeong, Dae-Ha;Kim, Dong-Hyun;Kim, Myung-Hwan
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.5
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    • pp.363-373
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    • 2014
  • In this study, computational multi-body dynamic analyses for the drivetrain system of a 5 MW class offshore wind turbine have been conducted using efficient equivalent modeling technique based on the design guideline of GL 2010. The present drivetrain system is originally modeled and its related system data is adopted from the NREL 5 MW wind turbine model. Efficient computational method for the drivetrain system dynamics is proposed based on an international guideline for the certification of wind turbine. Structural dynamic behaviors of drivetrain system with blade, hub, shaft, gearbox, supports, brake disk, coupling, and electric generator have been analyzed and the results for natural frequency and equivalent torsional stiffness of the drivetrain system are presented in detail. It is finally shown that the present multi-body dynamic analysis method gives good agreement with the previous results of the 5 MW class wind turbine system.

The Integrated Design and Analysis of Manufacturing Lines (II) - Continuous Design, Analysis and Optimization through Digital Virtual Manufacturing (제조라인 통합 설계 및 분석(II) - 디지털 가상생산 기술 적용을 통한 지속적인 라인 설계, 분석 및 최적화 프로세스)

  • Choi, SangSu;Sung, Nakyun;Shin, Yeonsik;Noh, Sang Do
    • Korean Journal of Computational Design and Engineering
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    • v.19 no.2
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    • pp.148-156
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    • 2014
  • Generally, over 95% of manufacturing cost is determined in the design and manufacturing preparation step, especially a great part of productivity is determined in the manufacturing preparation step. In order to improve the manufacturing competitiveness, we have to verify the problems that can be occurred in the production step and remove the unnecessary factors in the manufacturing preparation step. Thus, manufacturing industries are adopting digital manufacturing system based on modeling & simulation. In this paper, we introduce e-FEED system (electronic based Front End Engineering and Design) that is the integrated design and analysis system for optimized manufacturing line development based on simulation automation and explain the work process (Design, Analysis and Optimization) about manufacturing line development using e-FEED system. Also, the effect is described through the real implementation cases.

A Study on CAD/CAE Integration for Design Optimization of Mold Cooling Problem (CAD와 유한요소해석을 연계한 금형 냉각문제의 설계최적화에 대한 연구)

  • 오동길;류동화;최주호;김준범;하덕식
    • Korean Journal of Computational Design and Engineering
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    • v.9 no.2
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    • pp.93-101
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    • 2004
  • In mechanical design, optimization procedures have mostly been implemented solely by CAE codes combined by optimization routine, in which the model is built, analyzed and optimized. In the complex geometries, however, CAD is indispensable tool for the efficient and accurate modeling. This paper presents a method to carry out optimization, in which CAD and CAE are used for modeling and analysis respectively and integrated in an optimization routine. Application Programming Interface (API) function is exploited to automate CAD modeling, which enables direct access to CAD. The advantage of this method is that the user can create very complex object in Parametric and automated way, which is impossible in CAE codes. Unigraphics and ANSYS are adopted as CAD and CAE tools. In ANSYS, automated analysis is done using codes made by a script language, APDL(ANSYS Parametric Design Language). Optimization is conducted by VisualDOC and IDESIGN respectively. As an illustrative example, a mold design problem is studied, which is to minimize temperature deviation over a diagonal line of the surface of the mold in contact with hot glass.

OpenBIM-based Mapping System Development for Geometry Information Exchange of Architectural Components (건축부재 형상정보 교환을 위한 개방형BIM 기반의 매핑 시스템 개발)

  • Park, Seunghwa;Kim, Inhan;Lee, Jiah
    • Korean Journal of Computational Design and Engineering
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    • v.19 no.2
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    • pp.182-190
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    • 2014
  • Parametric modeling is one of BIM's characteristics and BIM have being utilized for constructability analysis, energy efficiency analysis, and so on in diverse construction field. However, parametric information's interoperation is not solved until now because different BIM tools have specific algorithm and methods to generate geometric information. To solve the problem, previous research suggested IFC-XML methodology. In this paper, authors studied connections between IFC-XML structure and script-based modeling commends to make libraries in commercial BIM tools such as ArchiCAD$^{TM}$ and Digital Project$^{TM}$. In addition, they made commends mapping tables to exchange geometry information of architectural components. Moreover, mapping system was developed to certify the mapping tables which is classified modeling commends. Finally, translated architectural component model was confirmed using exchanged geometry information in browser.

Blast Performance Evaluation based on Finite Element Analysis for Reinforced Concrete Columns with Shear and Flexure Failure Modes (유한요소해석 기반 휨 및 전단 파괴형 철근콘크리트 기둥의 폭발 성능평가)

  • Ye-Eun Kim;Quoc To Bao;Kihak Lee;Jiuk Shin
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.36 no.5
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    • pp.307-314
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    • 2023
  • This study aims to evaluate the blast performance of shear and flexure failure modes of reinforced concrete columns using finite-element analyses. To accomplish this goal, finite-element models of flexure- and shear-governed columns were developed and validated using previous experimental results. A blast simulation model was developed using a coupling-modeling method, and the modeling method was applied to the validated-column models. Blast responses were obtained for various blast loading scenarios, and the blast performance was determined using limits based on ductility and axial loading capacity.

Feature-Based Non-manifold Geometric Modeling System to Provide Integrated Environment for Design and Analysis of Injection Molding Products (사출 성형 제품의 설계 및 해석의 통합 환경을 제공하기 위한 특징 형상 기반 비다양체 모델링 시스템의 개발)

  • 이상헌;이건우
    • Korean Journal of Computational Design and Engineering
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    • v.1 no.2
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    • pp.133-149
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    • 1996
  • In order to reduce the trial-and-errors in design and production of injection molded plastic parts, there has been much research effort not only on CAE systems which simulate the injection molding process, but also on CAD systems which support initial design and re-design of plastic parts and their molds. The CAD systems and CAE systems have been developed independently with being built on different basis. That is, CAD systems manipulate the part shapes and the design features in a complete solid model, while CAE systems work on shell meshes generated on the abstract sheet model or medial surface of the part. Therefore, it is required to support the two types of geometric models and feature information in one environment to integrate CAD and CAE systems for accelerating the design speed. A feature-based non-manifold geometric modeling system has been developed to provide an integrated environment for design and analysis of injection molding products. In this system, the geometric models for CAD and CAE systems are represented by a non-manifold boundary representation and they are merged into a single geometric model. The suitable form of geometric model for any application can be extracted from this model. In addition, the feature deletion and interaction problem of the feature-based design system has been solved clearly by introducing the non-manifold Boolean operation based on 'merge and selection' algorithm. The sheet modeling capabilities were also developed for easy modeling of thin plastic parts.

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Identifying the Significance of Factors Affecting Creep of Concrete: A Probabilistic Analysis of RILEM Database

  • Adam, Ihab;Taha, Mahmoud M. Reda
    • International Journal of Concrete Structures and Materials
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    • v.5 no.2
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    • pp.97-111
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    • 2011
  • Modeling creep of concrete has been one of the most challenging problems in concrete. Over the years, research has proven the significance of creep and its ability to influence structural behavior through loss of prestress, violation of serviceability limit states or stress redistribution. Because of this, interest in modeling and simulation of creep has grown significantly. A research program was planned to investigate the significance of different factors affecting creep of concrete. This research investigation is divided into two folds: first, an in-depth study of the RILEM creep database and development of a homogenous database that can be used for blind computational analysis. Second: developing a probabilistic Bayesian screening method that enables identifying the significance of the different factors affecting creep of concrete. The probabilistic analysis revealed a group of interacting parameters that seem to significantly influence creep of concrete.

Seismic Assessment and Performance of Nonstructural Components Affected by Structural Modeling

  • Hur, Jieun;Althoff, Eric;Sezen, Halil;Denning, Richard;Aldemir, Tunc
    • Nuclear Engineering and Technology
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    • v.49 no.2
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    • pp.387-394
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    • 2017
  • Seismic probabilistic risk assessment (SPRA) requires a large number of simulations to evaluate the seismic vulnerability of structural and nonstructural components in nuclear power plants. The effect of structural modeling and analysis assumptions on dynamic analysis of 3D and simplified 2D stick models of auxiliary buildings and the attached nonstructural components is investigated. Dynamic characteristics and seismic performance of building models are also evaluated, as well as the computational accuracy of the models. The presented results provide a better understanding of the dynamic behavior and seismic performance of auxiliary buildings. The results also help to quantify the impact of uncertainties associated with modeling and analysis of simplified numerical models of structural and nonstructural components subjected to seismic shaking on the predicted seismic failure probabilities of these systems.