Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Computational Structural Engineering Institute of Korea
Journal Basic Information
Journal DOI :
The Computational Structural Engineering Institute
Editor in Chief :
Volume & Issues
Volume 24, Issue 6 - Dec 2011
Volume 24, Issue 5 - Oct 2011
Volume 24, Issue 4 - Aug 2011
Volume 24, Issue 3 - Jun 2011
Volume 24, Issue 2 - Apr 2011
Volume 24, Issue 1 - Feb 2011
Selecting the target year
Isogeometric Shape Design Optimization of Structures Subjected to Design-dependent Loads
Yoon, Min-Ho ; Koo, Bon-Yong ; Ha, Seung-Hyun ; Cho, Seon-Ho ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 1~7
In this paper, based on an isogeometric approach, we have developed a shape design optimization method for plane elasticity problems subjected to design-dependent loads. The conventional shape optimization using the finite element method has some difficulties in the parameterization of geometry. In an isogeometric analysis, however, the geometric properties are already embedded in the B-spline basis functions and control points so that it has potential capability to overcome the aforementioned difficulties. The solution space for the response analysis can be represented in terms of the same NURBS basis functions to represent the geometry, which yields a precise analysis model that exactly represents the normal and curvature depending on the applied loads. A continuum-based isogeometric adjoint sensitivity is extensively derived for the plane elasticity problems under the design-dependent loads. Through some numerical examples, the developed isogeometric sensitivity analysis method is verified to show excellent agreement with finite difference sensitivity.
Analysis of Mechanical Response of Two-phase Polycrystalline Microstructures with Distinctive Topology of Phase Clustering
Chung, Sang-Yeop ; Han, Tong-Seok ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 9~16
An approach to understand the phase distribution in a multi-phase polycrystalline material is important since it can affect material properties and mechanical behaviors. A proper method is needed to describe the phase distribution. For this purpose, contiguity and probability functions(two-point correlation and lineal-path functions) are investigated for representing the phase distributions of microstructures. The mechanical behaviors are evaluated using the finite element method. The characteristics of probability functions and mechanical reponses of virtual samples are represented. It is confirmed that the topology of phase clustering affects the mechanical behavior of materials and that the strength is reduced as the clustering size increases.
Strength Prediction of Kraft Paperboard under Combined Stress
Lim, Won-Kyun ; Jeong, Woo-Kil ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 17~22
Based on the form of the Tsai-Hill criterion, a new failure criterion for anisotropic material subjected to combined stress is developed and demonstrated. It is capable of accurately calculating the strength of anisotropic materials. The generality and accuracy of the present failure criterion are illustrated by examination through the use of Kraft paperboards under various loading conditions. Compared to the Tsai-Hill theory, which is much too conservative at high levels of shear stress, the present criterion has a good agreement with the experimental data. It also has the ability to calculate the strength more simply, compared to the Tan-Cheng theory.
Experimental Study on Shear Strength of Concrete Deep Beam Reinforced FRP Bars
Cho, Jang-Se ; Kim, Min-Sook ; Lee, Young-Hak ; Kim, Hee-Cheul ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 23~31
This study carried out shear experiment for concrete deep beam reinforced FRP(Fiber Reinforced Polymers) bar to investigate shear strength of deep beam. The test conducted for 15 specimens, and the variables were shear span-to-depth ratio, reinforcement ratio, effective depth, reinforcement components of shear strength. crack, deflection are investigated based on shear experimental. We compared shear strength using ACI 318-08 STM with proposed equations that considered arching action according to shear span-to-depth ratio. Consequently shear strength of deep beam reinforced FRP bar presented higher shear strength than steel bar. ACI STM's predictions are better accurate than other predicting equations.
Modeling Technologies for Unbonded Post-Tension Systems
Kang, Thomas H.K. ; Rha, Chang-Soon ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 33~41
This study presents modeling technologies applicable to an unbonded post-tension system using a finite element software package. In this study, both direct modeling method and multiple spring method were used. The direct modeling method adopts tube-to-tube contact elements to represent the physical feature of a post-tension system. The multiple spring method uses virtual tendons attached to the real tendons using a number of rigid axial springs that freely rotate at the ends. Both modeling technologies provide accurate predictions. However, only the multiple spring method provides numerically stable and reliable responses with a consideration of concrete tension stiffening effects. Therefore, the multiple spring method turned out to be a generally applicable modeling technology for the unbonded post-tension system. Comparisons were made for the analytical and experimental results for the verification of the selected method, and parameter studies were carried out to confirm the appropriateness of the modeling assumptions and parameters adopted in the analysis.
Experimental Study on Bond Strength of Deformed Bars in Artificial Lightweight Aggregate Concrete
Cho, Jang-Se ; La, Sung-Jun ; Kim, Min-Sook ; Lee, Young-Hak ; Kim, Hee-Cheul ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 43~53
For reinforced concrete members, the bond strength is one of the important factors between two materials: concrete and reinforcing element. This study concerns the bond strength of deformed bars in artificial lightweight aggregate concrete by pull-out test. 144 cubic specimens were manufactured for the test. concrete compressive strength, size of deformed bar and embedment lengths were considered as variables in this study. Normal concrete with W/C ratio 50% specimens were tested for the comparison. Test results included the bond stress-slip responses and modes of failure. Bond strength increased with an increase of compressive strength of concrete according to W/C ratio. The equation of bond stress of polymer-modified lightweight aggregate concrete were proposed by regression analysis based on the result.
On the Structural Analysis Using the Isogeometry Analysis Approach
Lee, Joo-Sung ; Chang, Kyoung-Sik ; Roh, Myoung-Il ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 55~60
In the present work, isogeometric analysis in linear elasticity problem is conducted using the basis functions from NURBS. The objectives of isogeometric analysis introduced is to integrate both geometric modeling(CAD) and computational analysis(CAE), and this can be accomplished from direct usage of geometric modeling by NURBS as the computational mesh. The merit of the isogeometry analysis is that NURBS surface are able to represent exact geometry from the control points and knot vectors, and also subsequent refinement is relatively simple relatively. In order to verify the computer codes developed in this study, it has been applied to two structural models of which geometry are simple ; 1) circular cylinder subjected to the constant internal pressure loading, 2) square plate with circular hole at center subjected to uniform tension. The exact solutions of these two models are available. Convergence of the approximate solutions by the present code for the isogeometry analysis are investigated by mesh refinement with inserting knots (h-refinement) and by mesh refinement with order elevation of the basis functions (p-refinement).
Shape Optimization of Structural Members Based on Isogeometry Concept
Lee, Joo-Sung ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 61~67
This study is concerned with the shape optimization of structural members frequently found in critical area in a structure system, that is, highly stressed zone. Isogeometry analysis is well known to be the very efficient way to integrate the geometric modeling(CAD) and computational analysis(CAE). This can be accomplished by directly using the geometric modeling by NURBS(Non-Uniform Rational Basis Spline). In this study, an efficient computer code adopting the isogeometry concept has been developed for the structural analysis, in which CAD information can be directly used in the finite element modeling. In order to show the validity of the present code, the present results are compared with those by using the commercial package, that is, MSC/NASTRAN. The present isogeometric analysis procedure has been integrated with the optimization procedure to deal with the optimization problem found in the context of structural mechanics. The present system has been successfully applied to the shape optimization of cantilever structure having bracket. From the present study, it can be seen the validity of the present approach and computer codes developed in this study. This paper ends with some discussions about the practical usefulness of the present approach which is based on isogeometry analysis, and extension of the present study.
Fuzzy Control of Smart TMD using Multi-Objective Genetic Algorithm
Kang, Joo-Won ; Kim, Hyun-Su ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 69~78
In this study, an optimization method using multi-objective genetic algorithm(MOGA) has been proposed to develop a fuzzy control algorithm that can effectively control a smart tuned mass damper(TMD). A 76-story benchmark building subjected to wind load was selected as an example structure. The smart TMD consists of 100kN MR damper and the natural period of the smart TMD was tuned to the first mode natural period of the example structure. Damping force of MR damper is controlled to reduce the wind-induced responses of the example structure by a fuzzy logic controller. Two input variables of the fuzzy logic controller are the acceleration of 75th floor and the displacement of the smart TMD and the output variable is the command voltage sent to MR damper. Multi-objective genetic algorithm(NSGA-II) was used for optimization of the fuzzy logic controller and the acceleration of 75th story and the displacement of the smart TMD were used as objective function. After optimization, a series of fuzzy logic controllers which could appropriately reduce both wind responses of the building and smart TMD were obtained. Based on numerical results, it has been shown that the control performance of the smart TMD is much better than that of the passive TMD and it is even better than that of the sample active TMD in some cases.
Analysis of BWIM Signal Variation Due to Different Vehicle Travelling Conditions Using Field Measurement and Numerical Analysis
Lee, Jung-Whee ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 79~85
Bridge Weigh-in-Motion(BWIM) system calculates a travelling vehicle's weight without interruption of traffic flow by analyzing the signals that are acquired from various sensors installed in the bridge. BWIM system or data accumulated from the BWIM system can be utilized to development of updated live load model for highway bridge design, fatigue load model for estimation of remaining life of bridges, etc. Field test with moving trucks including various load cases should be performed to guarantee successful development of precise BWIM system. In this paper, a numerical simulation technique is adopted as an alternative or supplement to the vehicle traveling test that is indispensible but expensive in time and budget. The constructed numerical model is validated by comparison experimentally measured signal with numerically generated signal. Also vehicles with various dynamic characteristics and travelling conditions are considered in numerical simulation to investigate the variation of bridge responses. Considered parameters in the numerical study are vehicle velocity, natural frequency of the vehicle, height of entry bump, and lateral position of the vehicle. By analyzing the results, it is revealed that the lateral position and natural frequency of the vehicle should be considered to increase precision of developing BWIM system. Since generation of vehicle travelling signal by the numerical simulation technique costs much less than field test, a large number of test parameters can effectively be considered to validate the developed BWIM algorithm. Also, when artificial neural network technique is applied, voluminous data set required for training and testing of the neural network can be prepared by numerical generation. Consequently, proposed numerical simulation technique may contribute to improve precision and performance of BWIM systems.
Practical Determination Method of Initial Cable Forces in Cable-Stayed Bridges
Song, Yo-Han ; Kim, Moon-Young ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 87~95
A rational method for determination of initial cable forces in cable-stayed bridges without complicated nonlinear analysis is presented. Initial shape analysis for cable-stayed bridges should be able to find optimizated initial cable forces and unstrained length that minimize deflection and vending moments of the deck and pylon. A presented method utilizing the idea of force equilibrium organizes initial shape analysis for each types of cable-stayed bridges. The results of that analysis were compared to several existing methods for 2D numerical examples. And for 3D actual bridges, the improved TCUD method was performed to demonstrate the accuracy of this study.
Inverse Estimation of Viscoplastic Properties of Solder Alloy Using Moir
Interferometry and Computer Model Calibration
Gang, Jin-Hyuk ; Lee, Bong-Hee ; Joo, Jin-Won ; Choi, Joo-Ho ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 97~106
In this study, viscoplastic material properties of solder alloy which is used in the electronics packages are inversely estimated. A specimen is fabricated to this end, and an experiment is conducted to examine deformation by Moir
interferometry. As a result of the experiment, bending displacement of the specimen and shear strain of the solder are obtained. A viscoplastic finite element analysis procedure is established, and the material parameters are determined to match closely with the experiments. The uncertainties which include inherent experimental error and insufficient data of experiments are addressed by using the method of computer model calibration. As a result, material parameters are identified in the form of confidence interval, and the displacements and strains using these parameters are predicted in the form the prediction interval.
Damage Monitoring of PSC Girder Bridges based on Acceleration -Impedance Signals under Uncertain Temperature Conditions
Hong, Dong-Soo ; Kim, Jeong-Tae ;
Journal of the Computational Structural Engineering Institute of Korea, volume 24, issue 1, 2011, Pages 107~117
In this study, the effect of temperature-induced uncertainty to damage monitoring using acceleration-impedance response features is analyzed for presterssed concrete(PSC) girder bridges. Firstly, a damage monitoring algorithm using global and local vibration features is designed. As global and local features, acceleration and electro-mechanical impedance features are selected respectively. Secondly, the temperature effect on the acceleration and impedance features for a lab-scaled PSC girder is experimentally analyzed. From the experimental results, compensation models for temperature-acceleration features and temperature-impedance features are estimated. Finally, the feasibility of the acceleration-impedance-based damage monitoring technique using the compensation model is evaluated in the PSC girder for which a set of prestress-loss and flexural stiffness loss cases were dynamically tested.