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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 20, Issue 6 - Dec 2007
Volume 20, Issue 5 - Oct 2007
Volume 20, Issue 4 - Aug 2007
Volume 20, Issue 3 - Jun 2007
Volume 20, Issue 2 - Apr 2007
Volume 20, Issue 1 - Feb 2007
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Study of Failure Mode and Static Behavior of Lightweight FRP Truss Bridge Deck System
Jung, Woo-Young ; Lee, Hyung-Kil ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 511~520
There is a concern with worldwide deterioration of highway bridges, particularly reinforced concrete. The advantages of fibre reinforced plastic(FRP) composites over conventional materials motivate their use in highway bridges for replacement of structures. Recently, an FRP deck has been installed on a state highway, located in New York State, as an experimental project. In this paper, a systematic approach for analysis of this FRP deck bridge is presented. Multi-step linear numerical analyses have been performed using the finite element method to study the structural behavior and the possible failure mechanism of the FRP deck-superstructure system. Deck's self-weight and ply orientations at the interface between steel girders and FRP deck are considered in this study. From this research, the results of the numerical analyses were corroborated with field test results. Analytical results reveal several potential failure mechanism for the FRP deck and truss bridge system. The results presented in this study may be used to propose engineering design guideline for new and replacement FRP bridge deck structure.
Transient Dynamic Stress Analysis of Transversely Isotropic Cylinders Subject to Longitudinal Impact
Oh, Guen ; Sim, Woo-Jin ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 521~532
Elastic wave propagations in the semi-infinite transversely isotropic cylinder under various kinds of longitudinal impact loads are analyzed using the axisymmetric finite element method and Houbolt time-integration scheme. For which the finite element program is newly constructed and verified through the comparison of present numerical results with those by other researchers. E-type glass-epoxy composite cylinders with different fiber volume fractions are adopted and studied in detail with dynamic responses of the isotropic cylinder. Three dimensional wave motions are given in graphic form to show the realistic view of the wave propagation. Nondimensionalized dynamic characteristic variables which relate the size of finite element mesh, the time step, and the wave speed are presented for obtaining accurate and stable numerical results.
The Selective p-Distribution for Adaptive Refinement of L-Shaped Plates Subiected to Bending
Woo, Kwang-Sung ; Jo, Jun-Hyung ; Lee, Seung-Joon ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 533~541
The Zienkiewicz-Zhu(Z/Z) error estimate is slightly modified for the hierarchical p-refinement, and is then applied to L-shaped plates subjected to bending to demonstrate its effectiveness. An adaptive procedure in finite element analysis is presented by p-refinement of meshes in conjunction with a posteriori error estimator that is based on the superconvergent patch recovery(SPR) technique. The modified Z/Z error estimate p-refinement is different from the conventional approach because the high order shape functions based on integrals of Legendre polynomials are used to interpolate displacements within an element, on the other hand, the same order of basis function based on Pascal's triangle tree is also used to interpolate recovered stresses. The least-square method is used to fit a polynomial to the stresses computed at the sampling points. The strategy of finding a nearly optimal distribution of polynomial degrees on a fixed finite element mesh is discussed such that a particular element has to be refined automatically to obtain an acceptable level of accuracy by increasing p-levels non-uniformly or selectively. It is noted that the error decreases rapidly with an increase in the number of degrees of freedom and the sequences of p-distributions obtained by the proposed error indicator closely follow the optimal trajectory.
An Analysis of Simplified Cable Stayed Bridge with FRP Components
Park, Jae-Gyun ; An, Il-Chan ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 543~550
As an emerging materials in construction fields, FRP(fiber reinforced polymer) has been used in many area of civil engineering for its light weight and high strength. In this study we chose the 2nd Jindo-Bridge as a prototype, and evaluate effect of replacing steel components to FRP components through simplified 3D linear analysis. Static and modal analysis are done and the analysis results are compared with steel case analysis. From the static analysis results, the maximum stress of each component and maximum displacement of middle span are compared. Due to the reduction of deadload, the FRP structure causes less deflection than the original steel structure and from the reduced section (cable) analysis we confirmed the previous result. The occurrence wind velocity of flutter is compared by the frequency ratio.
Optimal Design of the Safety Valve by Response Surface Method
Lee, Sang-Woo ; Shin, Dae-Young ; Byun, Cheol-Woong ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 551~556
High pressure storage of the agent gas in fire suppression system was composed of tank, main valve and safety valve, which prevents the fracture of the high pressure storage. The safety valve has circular thin plate as fracture plate that was destroyed over fracture pressure. When inner pressure of the storage is reached the fracture pressure, the safety valve discharges gas and degrades simultaneously the inner pressure of the storage. There are design variables such as flow path diameter, inner diameter of the plastic packing ring, thickness of plate and fillet radius. In this variables, thickness of plate is set to be a value of 0.2mm. The main effect of variables on the inner pressure, has been decided using factorial design and statistical analysis. Therefore, the relation of variables are expressed by regression equation. It is disclosed results that the difference of fracture pressures between the equation and experiment has
. Finally, using response surface method, the optimal design of the safety valve could be decided with safety pressure of 25MPa, where the fracture occurs on circular thin plate.
Active Control System for Mitigation of Cable Vibration in Cable-Stayed Bridges
Hwang, In-Ho ; Jeong, Cheol-Oh ; Lee, Jong-Han ; Lee, Jong-Seh ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 557~563
Rain-wind induced cable vibration can cause serious problems in cable-stayed bridge. External dampers attached to the cables have become widely accepted as an effective means for stay-cable vibration suppression. For very long stay-cables, however, such damper systems are rendered ineffective, as the dampers need be attached near the end of cables for aesthetic reasons. A recent study by the authors proposed that a movable anchorage system is replaced direct fixed support of the cable with a support through a bearing and damper. This paper extends the previous work by adding active control system to mitigate the cable vibration. The response of a cable with the proposed active control system is obtained and then compared to those of the cable with and without an external passive damper. The results show that the active control system can provide superior protection than the passive control system for a cable vibration.
Kinematic Study for the Structural Analysis of the Frame Box of Vessel Engines
Lee, Jae-Hoon ; Choi, Jong-Ho ; Cho, Jin-Rae ; Lee, In-Soo ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 565~572
This paper addresses the kinematic study for the structural analysis of the S60ME-C multi-cylinder vessel engine. The load conditions such as the lateral force and the reaction force by the crank-shaft are required for the FEM analysis. The driving parts in vessel engine are assumed to be in frictionless rigid plane motion. We analytically derive dynamic forces for a single cylinder by using the dynamic force equilibrium. But, for the structural analysis for a single cylinder block, we use the loading conditions of two neighboring cylinders. Meanwhile, we use the single cylinder's loading condition to calculate the multi-cylinder's loading conditions, because each cylinder shows a cyclic loading pattern with respect to the crank arm's rotation angle.
Fatigue Life Estimation for Welded Parts of Marine Vessel Engine Frame Box by Utilizing Finite Element Analysis
Lee, Jae-Hoon ; Choi, Jong-Ho ; Cho, Jin-Rae ; Lee, In-Soo ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 573~580
This paper presents the numerical estimation of the fatigue life for the frame box's welded parts of the marine vessel engine S60MC-C. The time-variations of the effective stresses at the critical points during a piston cycle are computed through the finite element analysis, by applying the dynamic loadings that were analytically derived in the previous paper. The fatigue lives of the welded parts are estimated by making use of the hot-spot stress extrapolation and the Palmgren-miner cumulative damage rule.
Elastica of Cantilever Column with Constant Volume Subjected to Combined Loads
Lee, Byoung-Koo ; Li, Guangfan ; Yoon, Hee-Min ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 581~592
This paper deals with the elastica of deflected cantilever column with the constant volume. The columns are subjected to combined loads consisted of an axial compressive load and a couple moment at the free end. Differential equations governing the elastica of such column are derived, in which both the effects of taper type and shear deformation are included. Three kinds of taper types are considered: linear, parabolic and sinusoidal tapers. Differential equations are solved numerically to obtain the elastica of objective columns. The effects of various system parameters on the elastica are investigated extensively. Experimental studies were carried out in order to verify the theoretical results of non-linear behavior of the elasticas.
Effects of Interactions between the Concrete Deck and Steel Girders on the Dynamic Behavior of Simply Supported Skew Bridges
Moon, Seong-Kwon ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 593~604
Although composite construction has more mechanical advantages compared to noncomposite construction, the design of noncomposite construction for skew bridges with large skew angels has been often checked because composite construction may cause large stresses in the bridge deck. In this study, the analytical model considered dynamic behaviors for noncomposite skew bridges was proposed. Using the proposed analytical model, the validity of the application of noncomposite construction to skew bridges was checked. Also, the effects of interactions between the concrete deck and steel girders such as composite construction, partial composite construction, and noncomposite construction on the dynamic characteristics and dynamic behaviors of simply supported skew bridges were investigated. A series of parametric studies for the total 27 skew bridges was conducted with respect to parameters such as girder spacing, skew angle, and deck aspect ratio. Although the slip at the interfaces between the concrete deck and steel girders results in the reduction of seismic total base shear in the transverse direction due to period elongation, it causes an undesirable behavior of skew bridges by the modification in mode shapes and distributions of stiffness. Shear connectors placed by minimum requirements for partial composite action have an effect on reducing the girder stresses and deck stresses; except case of some skew bridges, the magnitude of the girder stresses and deck stresses obtained from partial composite skew bridges is similar to or slightly more than those acquired from composite skew bridges.
A Study on GUI Development of Structural Analysis of LNG Pump Tower
Lee, Kang-Su ; Son, Choong-Yul ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 605~613
The purpose of this study is to develop a structural analysis system of LNG pump tower structure. The system affords to build optimized finite element model and procedure of the pump tower structure. The pump tower structure is one of the most important components of LNG (liquefied natural gas) carriers. The pump tower structure is subject to sloshing load of LNG induced by ship motion depending on filling ratio. Three typer of loading components, which are thermal, inertia and self-gravity are considered in the analysis. The finite element analysis is performed with ANSYS commercial code. The failure of each members can be evaluated of API unity and punching shear in ABS rule. The GUI is newly developed using Tcl/tk script language. All these design and analysis procedures are embedded in to the analysis system successfully.
A Study on the Frequency Characteristics of Tubular and Jacket Type Tower for Offshore Wind Turbine Tower
Lee, Kang-Su ; Lee, Jung-Tak ; Son, Choong-Yul ; Kim, Keon-Hoon ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 615~621
Wind power generation is one of the promising gateways that will solve the energy crisis in the future. The wind power generator studied so far is limited to static interpretation in the areas related to tower. This study broadly sets the form of tower as tubular and jacket, identifies the characteristics of each and aims to find and apply their trend to in actual design and manufacturing process. This paper identified the resonance frequency of tower at each mode and studied their features. Furthermore, this study identified the characteristics of the load that occurs in operation and the effect of additional mass incurring when installed in sea, and it compared the two types of tower and was able to predict their trend.
Probability Distribution of Displacement Response of Structures with Friction dampers Excited by Earthquake Loads Generated Using Kanai-Tajimi Filter
Youn, Kyung-Jo ; Park, Ji-Hun ; Min, Kyung-Won ; Lee, Sang-Hyun ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 623~628
The accurate peak response estimation of a seismically excited structure with frictional damping system(FDS) is very difficult since the structure with FDS shows nonlinear behavior dependent on the structural period, loading characteristics, and relative magnitude between the frictional force and the excitation load. Previous studies have estimated that by replacing a nonlinear system with an equivalent linear one or by employing the response spectrum obtained based on nonlinear time history and statistical analysis. In the case that an earthquake load is defined with probabilistic characteristics, the corresponding response of the structure with FDS has probabilistic distribution. In this study, nonlinear time history analyses were performed for the structure with FDS subjected to artificial earthquake loads generated using Kanai-Tajimi filter. An equation for the probability density function (PDF) of the displacement response is proposed by adapting the PDF of the normal distribution. Finally, coefficients of the proposed PDF are obtained by regression analysis of the statistical distribution of the time history responses. Finally the correlation between PDFs and statistical response distribution is presented.
A Study on Improving the Capacity of Absorbing Boundary Using Dashpot
Kim, Hee-Seok ; Lee, Jong-Seh ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 629~640
In this paper an analytical study is carried out to improve the capacity of absorbing boundary using dashpot, one of the most widely used absorbing boundaries in FEM. Using 2-D harmonic plane wave equation, absorbing boundary condition is modified to maximize its capacity according to the incident angle. Validity of the absorbing boundary conditions which is modified is investigated by adopting the solution of Miller and Pursey. The Miller and Pursey's problem is then numerically simulated using the finite element method. The absorption ratios are calculated by comparing the displacements at the absorbing boundary to those at the free field without the absorbing boundary. The numerical study is carried out through comparison of displacement at the interior region and the boundary of the numerical model.
Half-Scaled Substructure Test for the Performance Evaluation of a Transmission Tower subjected to Wind Load
Moon, Byoung-Wook ; Min, Kyung-Won ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 641~652
In this paper, a half-scaled substructure test was performed to evaluate the buckling and structural safety of an existing transmission tower subjected to wind load. A loading scheme was devised to reproduce the dead and wind loads of a prototype transmission tower, which uses a triangular jig that is mounted on the reduced model to which the similarity law of a half length was applied. As a result of the preliminary numerical analysis carried out to evaluate the stability of a specimen for the design load, is was confirmed that the calculated axial forces of tower leg members were distributed to
of an admissible buckling load. When the substructured transmission tower was loaded by 270% of its maximum admissible buckling load, it was failed due to the local buckling that is occurred in joints with weak constraints for out-of-plane behavior of leg members. By inspection of load-displacement curves, displacements and strains of members, it is considered that this local buckling was due to additional eccentric force by unbalanced deformation because the time that is reached to yielding stress due to the bending moment is different at each point of a same section.
An Estimation of Equivalent Heat Source for Thermal Analysis of Steel Deck Bridge under Pavement Procedure
Chung, Heung-Jin ; Yoo, Byoung-Chan ; Lee, Wan-Hoon ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 653~660
Since the temperature of asphalt for deck plate of steel bridge during paying procedure is relatively high as
, the temperature of deck plate of bridge rises mere than
and excessive displacement and stress could occur. In order to avoid undesirable failure of base plate and determine the optimal pavement pattern, a thorough thermal analysis is needed. General structural model which is made of beam and plate element should be modified for transient heat transfer analysis; asphalt pavement material and convection effect on surface of structure need to be added. A new technique with the Equivalent Heat Source (EHS) for numerical thermal analysis for steel bridge under thermal load of Guss asphalt pavement is proposed. Since plate/beam elements which were generally used for structural analysis for bridge cannot explain convection effect easily on plate/beam surface, EHS which is determined based on calculated temperature with convection effect is used. To verify the EHS proposed in this study, numerical analyses with plate elements are performed and the results are compared with estimated temperatures. EHS might be used for other thermal analyses of steel bridge such as welding residual stress analysis and bridge fire analysis.
Optimal Active-Control & Development of Optimization Algorithm for Reduction of Drag in Flow Problems(1) - Development of Optimization Algorithm and Techniques for Large-Scale and Highly Nonlinear Flow Problem
Bark, Jai-Hyeong ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 661~669
Eyer since the Prandtl's experiment in 1934 and X-21 airjet test in 1950 both attempting to reduce drag, it was found that controlling the velocities of surface for extremely fast-moving object in the air through suction or injection was highly effective and active method. To obtain the right amount of suction or injection, however, repetitive trial-and error parameter test has been still used up to now. This study started from an attempt to decide optimal amount of suction and injection of incompressible Navier-Stokes by employing optimization techniques. However, optimization with traditional methods are very limited, especially when Reynolds number gets high and many unexpected variables emerges. In earlier study, we have proposed an algorithm to solve this problem by using step by step method in analysis and introducing SQP method in optimization. In this study, we propose more effective and robust algorithm and techniques in solving flow optimization problem.
Optimal Active-Control & Development of Optimization Algorithm for Reduction of Drag in Flow Problems(2) - Verification of Developed Methodologies and Optimal Active-Control of Flow for Drag Reduction
Bark, Jai-Hyeong ;
Journal of the Computational Structural Engineering Institute of Korea, volume 20, issue 5, 2007, Pages 671~680
The objective of this work is to reduce drag on a bluff body within a viscous flow by applying suction or injection of fluid along the surface of the body. In addition to minimizing drag, the optimal solution tends to reduce boundary layer separation and flow recirculation. When discretized by finite elements, the optimal control problem can be posed as a large-scale nonlinearly-constrained optimization problem. The constraints correspond to the discretized form of the Navier-Stokes equations. Unfortunately, solving such large-scale problems directly is essentially intractable. We developed several Sequential Quadratic Programming methods that are tailored to the structure of the control problem. Example problems of laminar flow around an infinite cylinder in two dimensions are solved to demonstrate the methodology. We use these optimal control techniques to study the influence of number of suction/injection holes and location of holes on the resulting optimized flow. We compare the proposed SQP methods against one another, as well as against available methods from the literature, from the point of view of efficiency and robustness. The most efficient of the proposed methods is two orders of magnitude faster than existing methods.