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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Computational Structural Engineering Institute of Korea
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Journal DOI :
The Computational Structural Engineering Institute
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Volume & Issues
Volume 28, Issue 6 - Dec 2015
Volume 28, Issue 5 - Oct 2015
Volume 28, Issue 4 - Aug 2015
Volume 28, Issue 3 - Jun 2015
Volume 28, Issue 2 - Apr 2015
Volume 28, Issue 1 - Feb 2015
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Development of Computational Evaluation Method for Fatigue Crack Growth Rate based on Viscoplastic-Damage Model
Kim, Seul-Kee ; Kim, Jeong-Hyeon ; Lee, Chi-Seung ; Kim, Myung-Hyun ; Lee, Jae-Myung ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 1~8
DOI : 10.7734/COSEIK.2015.28.1.1
In this paper, computational evaluation method for fatigue crack growth rate(FCGR) based on material viscoplastic-damage model is proposed. Viscoplastic-damage model expressing material constitutive behavior of 7% nickel steel is introduced and is implemented into commercial finite element analysis(FEA) code, ABAQUS, as a user defined material subroutine(UMAT) for application in the FEA environments. Verification of developed UMAT and material parameters of material model are carried out by uniaxial tensile test simulations of 7% nickel steel. Moreover, jump-in-cycles procedure and rearrangement of critical damage are employed and also implemented to the ABAQUS UMAT for fatigue damage analysis. Typical FCGR test results such as relationship between crack length and number of cycles and relationship between da/dN and
could be obtained from FCGR test simulation using developed UMAT and these results are compared with experimental results in order to verify of proposed computational method.
Topology Design Optimization and Experimental Validation of Heat Conduction Problems
Cha, Song-Hyun ; Kim, Hyun-Seok ; Cho, Seonho ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 9~18
DOI : 10.7734/COSEIK.2015.28.1.9
In this paper, we verify the optimal topology design for heat conduction problems in steady stated which is obtained numerically using the adjoint design sensitivity analysis(DSA) method. In adjoint variable method(AVM), the already factorized system matrix is utilized to obtain the adjoint solution so that its computation cost is trivial for the sensitivity. For the topology optimization, the design variables are parameterized into normalized bulk material densities. The objective function and constraint are the thermal compliance of the structure and the allowable volume, respectively. For the experimental validation of the optimal topology design, we compare the results with those that have identical volume but designed intuitively using a thermal imaging camera. To manufacture the optimal design, we apply a simple numerical method to convert it into point cloud data and perform CAD modeling using commercial reverse engineering software. Based on the CAD model, we manufacture the optimal topology design by CNC.
Analyses of Structural Performances for RC High-Rise Residential Complex Building under Construction
Hwang, Young-Jin ; Kim, Jae-Yo ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 19~27
DOI : 10.7734/COSEIK.2015.28.1.19
Recently, the most of domestic high-rise residential complex buildings are constructed with reinforced concrete structures, which may bring structural problems during construction. This study is aimed to analyze structural safety and lateral load-resisting performance of RC high-rise residential complex building under construction. The tower-typed building with 60 floors is selected as a sample model, and numerical analyses are performed. The structural performances of building structures at construction stages, which are resulted form the analyses of numerical models completed up to 10th, 20th, 30th, 40th, 50th, or 60th floor, are compared to those of the completed building structure. For the comparisons of structural performances, modal shapes and fundamental periods of building structures, lateral load-resisting performances, and structural design performances of structural members are considered. The lateral displacement and story drift ratio are analyzed for lateral load-resisting performances, and comparisons of design ratios at construction and design stages are performed for structural design performances of structural members. The guideline of design loads and structural analysis schemes for checking the safety of RC high-rise building under construction is presented.
A Study on Weight Estimation of Moving Vehicles using Bridge Weigh-in-Motion Technique
Oh, Jun-Seok ; Park, Jooyoung ; Kim, Junkyeong ; Park, Seunghee ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 29~37
DOI : 10.7734/COSEIK.2015.28.1.29
In this study, the estimation of axial load and total axial load was conducted using Bridge Weigh-in-Motion(BWIM) technique which generally consists of devices for measuring the strain induced in the bridge by the vehicles. axle detectors for collecting information on vehicle velocity and axle spacing. and data acquisition equipment. Vehicle driving test for the development of the BWIM system is necessary but it needs much cost and time. In addition, it demands various driving conditions for the test. Thus, we need a numerical-simulation method for resolving the cost and time problems of vehicle driving tests, and a way of measuring bridge response according to various driving conditions. Using a bridge model reflecting the dynamic characteristic contributes to increased accuracy in numerical simulation. In this paper, we conduct a numerical simulation which reflects the dynamic characteristic of a bridge using the Bridge Weigh-in-Motion technique, and suggest overload vehicle enforcement technology.
A Parametric Study of Deflection Analysis of the Prestressed Beams using Finite Element Analysis
Park, Ha Eun ; Choi, Jin Woong ; Kim, Min Sook ; Lee, Young Hak ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 39~46
DOI : 10.7734/COSEIK.2015.28.1.39
The purpose of this study is to analyze the deflection of the prestressed beams. In this paper, a finite element model for deflections of prestressed beams is presented. Proposed finite element model was verified comparing with existing experimental results, and it showed a good agreement with the experimental results. Also, a parametric study has been conducted to analyze the influence of eccentricity, span-depth ratio, and prestressing force. The finite element model results were compared with hand calculation results. Deflections were increased as the eccentricity decreases, the span-depth ratio increases, and the prestressing force decreases. Hand calculation overestimated the deflection when the eccectricity or prestressing force is too small.
Dynamic Characteristics Recovery of Delaminated Composite Structure
Sohn, Jung Woo ; Kim, Heung Soo ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 47~51
DOI : 10.7734/COSEIK.2015.28.1.47
In this paper, feasibility of dynamic characteristics recovery of delaminated composite structure is numerically studied by using active control algorithm and piezoelectric actuator. Macro-fiber composite(MFC), which has great flexibility and high actuating force, is considered as an actuator in this work. After construction of finite element model for delaminated composite structure based on improved layerwise theory, modal characteristics are investigated and changes of natural frequencies and mode shapes, caused by delamination, are observed. Then, active control algorithm is realized and implemented to system model and control performances are numerically evaluated. Dynamic characteristics of delaminated composite structure are effectively recovered to those of healthy composite structure.
Buckling Behaviors of Single-Layered Lattice Dome under Radial Uniform Loads
Kim, Choong-Man ; Yu, Eun-Jong ; Rha, Chang-Soon ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 53~61
DOI : 10.7734/COSEIK.2015.28.1.53
This paper presented the nonlinear behaviors of the single-layered lattice dome, which is widely used for the long-span structure system. The behaviors were analysed through the classical shell buckling theory as the single-layered lattice dome behaves like continum thin shell due to its geometric characteristics, and finite element analysis method using the software program Nastran. Shell buckling theory provides two types of buckling loads, the global- and member buckling, and finite element analysis provides the ultimate load of geometric nonlinear analysis as well as the buckling load of Eigen value solution. Two types of models for the lattice dome were analysed, that is rigid- and pin-jointed structure. Buckling load using the shell buckling theory for each type of lattice dome, governed by the minimum value of global buckling or member buckling load, resulted better estimation than the buckling load with Eigen value analysis. And it is useful to predict the buckling pattern, that is global buckling or member buckling.
Infrared Reflector Design using the Phase Field Method for Infrared Stealth Effect
Heo, Namjoon ; Yoo, Jeonghoon ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 63~69
DOI : 10.7734/COSEIK.2015.28.1.63
In this paper, infrared reflector design targeting infrared stealth effect is presented using structural optimization based on the phase field method. The analysis model was determined to accomplish the design that an incident infrared wave was reflected to a desired direction. The design process was to maximize the objective value at the measuring domain located in a target region and the design objective was set to the Poynting vector value which represents the energy flux. Optimization results were obtained according to the variation of some parameter values related to the phase field method. The model with a maximum objective value was selected as the final optimal model. The optimal model was modified to eliminate the gray scale using the cut-off method and it confirmed improved performance. In addition, to check the desired effect in the middle wave infrared range(MWIR), the analysis was performed by changing the input wavelength. The finite element analysis and optimization process were performed by using the commercial package COMSOL combined with the Matlab programming.
Fluid Structure Interaction Analysis of Membrane Type LNG CCS Experiencing the Sloshing Impact by Impinging Jet Model
Hwang, Se Yun ; Lee, Jang Hyun ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 71~78
DOI : 10.7734/COSEIK.2015.28.1.71
The reliable sloshing assessment methods for LNG CCS(cargo containment system) are important to satisfy the structural strength of the systems. Multiphase fluid flow of LNG and Gas Compressibility may have a large effect on excited pressures and structural response. Impinging jet model has been introduced to simulate the impact of the LNG sloshing and analyze structural response of LNG CCS as a practical FSI(fluid structure interaction) method. The practical method based on fluid structure interaction analysis is employed in order to evaluate the structural strength in actual scale for Mark III CCS. The numerical model is based on an Euler model that employs the CVFEM(control volume based finite element method). It includes the particle motion of gas to simulate not only the interphase interaction between LNG liquid and gas and the impact load on the LNG insulation box. The analysis results by proposed method are evaluated and discussed for an effectiveness of FSI analysis method.
A Numerical Study on the Alignment of Surface Structures on Silicon-germanium Thin Films under a Localized Modulation of Surface Diffusivity
Kim, Yun Young ; Han, Bong Koo ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 79~83
DOI : 10.7734/COSEIK.2015.28.1.79
This paper presents a numerical study on the alignment of ridge-like surface structures evolving on silicon-germanium thin films under localized modulation of surface diffusivity. A situation is considered in which the surface diffusion of film material is selectively promoted such that its morphology is perturbed to periodic patterns. To simulate the growth behavior, a governing equation is formulated taking the surface chemical potential into account, and its solution is numerically sought using a finite-difference method. Results show that an initially planar surface coalesces upon the diffusivity modulation, and the surface structures can be aligned by changing the frequency of modulation condition. This research suggests a bottom-up fabrication technique that can manage the regularity of surface structures for thin film devices.
A Study of Dynamic Instability for Sigmoid Functionally Graded Material Plates on Elastic Foundation
Lee, Won-Hong ; Han, Sung-Cheon ; Park, Weon-Tae ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 85~92
DOI : 10.7734/COSEIK.2015.28.1.85
This article presents the dynamic instability response of sigmoid functionally graded material plates on elastic foundation using the higher-order shear deformation theory. The higher-order shear deformation theory has ability to capture the quadratic variation of shear strain and consequently shear stress through the plate thickness. The governing equations are then written in the form of Mathieu-Hill equations and then Bolotin`s method is employed to determine the instability regions. The boundaries of the instability regions are represented in the dynamic load and excitation frequency plane. The results of dynamic instability analysis of sigmoid functionally graded material plate are presented using the Navier`s procedure to illustrate the effect of elastic foundation parameter on dynamic response. The relations between Winkler and Pasternak elastic foundation parameter are discussed by numerical results. Also, the effects of static load factor, power-law index and side-to-thickness ratio on dynamic instability analysis are investigated and discussed. In order to validate the present solutions, the reference solutions are used and discussed. The theoretical development as well as numerical solutions presented herein should serve as reference for the dynamic instability study of S-FGM plates.
Analysis Model for Approximate Evaluation of Stiffness for Semi-Rigid Connection of Wooden Structures
Cho, So-Hoon ; Lee, Heon-Woo ; Park, Moon-Jae ; Kim, Taejin ; Kim, Jong-Ho ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 93~100
DOI : 10.7734/COSEIK.2015.28.1.93
Modern wooden structures usually are connected with steel fastener type connectors. And joints using multiple connectors in wooden structures will form semi-rigid connection. If connection in wooden structure would be designed to be pinned joint, the underestimate for loads transmitted through connection, would result in the deficient capacity of resistance in connection. And if joints in wooden structures would be assumed to be fully-rigid joint, amount of fasteners needed at the connection could be excessively increased. It will give a bad effect in the view of beauty, constructability and economy. Estimate for the reasonable stiffness of connection might be essential in design of reasonable connection in wooden structure. This paper will suggest analysis modelling technique that can represent approximate stiffness of connections using a common analysis program for double shear connection in order to give help in performing easily the design of wooden structure. It is verified that the suggested approximate analysis modelling technique could represent the behavior in connection by comparing the analysis results with test results for tensile, bending moment.
A Numerical Model of Reinforced Concrete Members Exposed to Fire and After-Cooling Analysis
Hwang, Ju-Young ; Kwak, Hyo-Gyoung ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 1, 2015, Pages 101~113
DOI : 10.7734/COSEIK.2015.28.1.101
This paper introduces a numerical analysis method for reinforced-concrete(RC) members exposed to fire and proposes considerations in designing RC structures on the basis of the comparison between numerical results and design codes. The proposed analysis method consists of two procedures of the transient heat transfer analysis and the non-linear structural analysis. To exactly evaluate the structural behavior under fire, two material models are considered in this paper. One is "Under-Fire" condition for the material properties at the high temperature and the other one is "After-Cooling" condition for the material properties after cooling down to air temperature. The proposed method is validated through the correlation study between experimental data and numerical results. In advance, the obtained results show that the material properties which are fittable to the corresponding temperature must be taken into account for an accurate prediction of the ultimate resisting capacity of RC members. Finally, comparison of the numerical results with the design code of EN1992-1-2 also shows that the design code needs to be revised to reserve the safety of the fire-damaged structural member.