• Steel and Composite Structures
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• v.2 no.3
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• pp.161-170
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• 2002

The problem of the elastic buckling of a cylindrical liquid-storage tank subject to horizontal earthquake loading is considered. An equivalent static loading is used to represent the dynamic effect. A theoretical solution based on the nonlinear Fl$\ddot{u}$gge shell equations is developed, and numerical results are found using the new differential quadrature method. A second solution is obtained using the finite element package ADINA. A major motivation of the study was to show that the new method can serve to verify finite element solutions for cylindrical shell buckling problems. For this purpose the paper concludes with a comparison of buckling results for a number of cases covering a wide range in tank geometry.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.455-462
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• 1998

Analysis and design of vibrating machine foundations subjected to dynamic loads is a very complex problem. Thus it is difficult to set up an accurate analytical modeling. Generally, the design of foundations for vibrating machines has been performed by the equivalent static analysis which is generally based on engineer's experience and various assumptions The purpose of this study is to develop an integrated system which enables structural engineers to produce results of high quality within a short time in works related to structural analysis and design of foundation for vibrating machines. As the result of this study, level-up of application software is expected as well as improvement of quality in structural engineering and reduction of engineers' effort.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.131-138
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• 2002

The fuel handling machine handles the core assembly in refueling period of the reactor, it is necessary to predict the motion and structural integrity of it. The kinetic analysis of the fuel handling machine was carried out for the refueling motion. The reaction forces at the joints of machine were calculated with IDEAS code considering the weight of the machine and the loading force of the core assembly, Also, the structural analysis for the machine modeled by lumped-mass and beam elements was performed by using ANSYS code. The stresses and deformations were calculated for the equivalent static force based on the kinetic analysis and the seismic loads. The calculated displacements and stresses are quite low compared with allowable limits.

• Structural Engineering and Mechanics
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• v.6 no.4
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• pp.427-437
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• 1998

Flat plate constructions are structural systems which are directly placed on columns without any beams. Various solution methods have been introduced for the solution of flat plate structures under horizontal and vertical loads. In most of these solution methods, models comprising of one column and one plate have been studied. In other solutions, however, co-behavior of two reciprocal columns has been investigated. In this study, interrelations of all the columns on one storey have been examined. At the end of the study structure consisting of nine columns and four plates has been chosen as a model. Then unit moment has been successively applied to each of these columns and unit moments carried over the other columns have been found. By working out solutions far plates and columns varying in ratio, carry-over factors have been found and these factors given in tables. In addition, fixed-end moment factors on the columns arising due to vertical load were also calculated. Then citing slope-deflection equations to which these results could be applied, some examples of moment and horizontal equilibrium equations have been given.

• Journal of Korean Society of Steel Construction
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• v.18 no.2
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• pp.173-180
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• 2006

The seismic responses of a building are affected by the base soil conditions. In this study, linear time-history seismic analysis and nonlinear pushover static seismic analysis were performed to estimate the base shear forces of 3-, 5-, and 7-story steel buildings, considering the rigid and soft soil conditions. Foundation soil stiffness, based on the equivalent static stiffness formula, is used for the damper, one of the Link elements in SAP 2000. The base shear forces of the steel buildings, estimated through time-history analysis using the general-purpose structural-analysis program of SAP 2000, were compared with those calculated using the domestic seismic design code, the UBC-97 design response spectrum. and pushover static nonlinear analysis. The steel buildings designed for gravity and wind loads showed elastic responses with a moderate earthquake of 0.11 g, while the elastic soft-soil layer increased the displacement and the base shear force of the buildings due to soil-structure interaction and soil amplification. Therefore, considering the characteristics of the soft-soil layer, it is more reasonable to perform an elastic seismic analysis of a building's structure during weak or moderate earthquakes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.1009-1015
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• 2012

Valves are one of the most important components of a pipeline system in a nuclear power plant, and it is important to ensure their structural safety under seismic loads. A crucial aspect of structural safety verification is the seismic qualification, and therefore, an optimal shape design and experimental seismic qualification is necessary in case the configuration of the valve parts needs to be modified and their performance needs to be improved. Recently, intensive numerical analyses have been performed before the experimental verification in order to determine the appropriate design variables that satisfy the performance requirements under seismic loads. In this study, static and dynamic numerical structural analyses of a 200A butterfly valve for a nuclear power plant were performed according to the KEPIC MFA. The result of static analysis considering an equivalent static load under SSE condition gave an applied stress of 135 MPa. In addition, the result of dynamic analysis gave an applied stress of 183 MPa, where the CQC method using response spectrums was taken into account. These values are under the allowable strength of the materials used for manufacturing the butterfly valve, and therefore, its structural safety satisfies the requirements of KEPIC MFA.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.3
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• pp.133-140
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• 2012

In this study, 3 kinds of models about bike frame are simulated with static structural analysis, And fatigue life, damage and durability according to fatigue load are analyzed. A bike frame model with diamond type is compared with another model on the reinforced support with its type. In case of the reinforced support type, maximum equivalent stress or total deformation is shown with 10% or 20% more than the diamond type respectively. At both types of models, the trends of fatigue life and damage at both types are same. 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable among the cases of nonuniform fatigue loads. In case of 'Sample history' with the average stress of 0 to -1MPa and the amplitude stress of 0 to 1MPa, the possibility of maximum damage becomes 3%. This stress state can be shown with 6 times more than the damage possibility of 'SAE Bracket history' or 'SAE transmission'. In case of the reinforced support type, fatigue life becomes shorter and damage probability becomes larger at the right side installed with support than diamond type. The structural result of this study can be effectively utilized with the design on bike frame by investigating prevention and durability against its damage.

• Journal of the Earthquake Engineering Society of Korea
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• v.28 no.2
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• pp.93-101
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• 2024

Code-compliant seismic design should be essentially applied to realize the so-called emulative performance of precast concrete (PC) lateral force-resisting systems, and this study developed simple procedures to design precast industrial buildings with intermediate precast bearing wall systems considering both the effect of seismic and blast loads. Seismic design provisions specified in ACI 318 and ASCE 7 can be directly adopted, for which the so-called 1.5S_y condition is addressed in PC wall-to-wall and wall-to-base connections. Various coupling options were considered and addressed in the seismic design of wall-to-wall connections for the longitudinal and transverse design directions to secure optimized performance and better economic feasibility. On the other hand, two possible methods were adopted in blast analysis: 1) Equivalent static analysis (ESA) based on the simplified graphic method and 2) Incremental dynamic time-history analysis (IDTHA). The ESA is physically austere to use in practice for a typical industrial PC-bearing wall system. Still, it showed an overestimating trend in terms of the lateral deformation. The coupling action between precast wall segments appears to be inevitably required due to substantially large blast loads compared to seismic loads with increasing blast risk levels. Even with the coupled-precast shear walls, the design outcome obtained from the ESA method might not be entirely satisfactory to the drift criteria presented by the ASCE Blast Design Manual. This drawback can be overcome by addressing the IDTHA method, where all the design criteria were fully satisfied with precast shear walls' non-coupling and group-coupling strength, where each individual or grouped shear fence was designed to possess 1.5S_y for the seismic design.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.3
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• pp.141-148
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• 2022

In this study, the structural behavior of reinforced concrete members under simultaneous axial and blast loads was analyzed. Nonlinear dynamic analysis verification was performed using the experimental data of panels under fundamental blast load as well as those of reinforced concrete columns subjected to axial and blast loads. Because Autodyn is a program designed only for dynamic analysis, an analysis process is devised to simulate the initial stress state of members under static loads, such as axial loads. A total of 80 nonlinear dynamic finite element analysis procedures were conducted by selecting parameters corresponding to axial load ratios and scaled distances ranging 0%~70% and 1.1~2.0 (depending on the equivalent of TNT), respectively. The structural behavior was compared and analyzed with the corresponding degree of damage and maximum lateral displacement through the changes in axial load ratio and scaled distance. The results show that the maximum lateral displacement decreases due to the increase in column stiffness under axial loads. In view of the foregoing, the formulated analysis process is anticipated to be used in developing blast-resistant design models where structural behavior can be classified into three areas considering axial load ratios of 10%~30%, 30%~50%, and more than 50%.

• Steel and Composite Structures
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• v.15 no.5
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• pp.539-566
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• 2013

This paper summarises the results of a numerical study on the non linear response of steel concentric braced frames under monotonic and cyclic loads, using force-based finite elements with section fibre discretisation. The first part of the study is addressed to analyse the single brace response. A parametric analysis was carried out and discussed to evaluate the accuracy of the model, examining the influence of the initial camber, the material modelling, the type of force-based element, the number of integration points and the number of fibers. The second part of the paper is concerned with the modelling issues of whole braced structures. The effectiveness of the modelling approach is verified against the nonlinear static and dynamic behaviour of different type of bracing configurations. The model sensitivity to brace-to-brace interaction and the capability of the model to mimic the response of complex bracing systems is analyzed. The influence of different approaches for modelling the inertia, the equivalent viscous damping and the brace hysteretic response on the overall structural response are also investigated. Finally, on the basis of the performed numerical study general modelling recommendations are proposed.