• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.129-142
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• 2005

A semi-monocoque truncated cone structure, which is a main structure for the payload adapter of KSLV-I, was designed. Static test was performed to confirm the reliability of the cone structure under the design loads. Strains and displacements are measured during four load cases; the compressive axial, pure bending, pure shear, and combined loading conditions. The results showed that the cone structure satisfies the design requirements. An equivalent axial load was applied to the cone structure so that the global buckling of the cone structure occurred. The measured buckling load was compared with the predicted one by finite element method. The results show a good agreement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.2
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• pp.85-93
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• 1993

Base isolation systems are economic and efficient for the control of structural vibration. In this study, the base isolators of LRB(laminated rubber bearing) type which have been generally used are fabricated and tested. From the static and dynamic tests, the characteristics of the base isolators, considering strain-hardening, hysteretic damping and horizontal stiffnesses, etc., are verified and particularly the feasibility as base isolation devices is discussed. Consequently, the test results are compared with the analytical ones that are derived from idealization as a bilinear model.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.913-914
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• 2017

Structural analyses of a engine system is required in development stage for increasing structural reliability and reducing weight. Attitude of a launch vehicle during flight is controlled by combustion chamber rotation varying with TVC (thrust vector control) actuator displacements. In this study nonlinear static analysis is performed for a 75 tonf-class liquid rocket engine using before and after the TVC actuation.

• Journal of Korean Society of Steel Construction
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• v.13 no.2
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• pp.143-152
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• 2001

This paper presents are monotonic and cyclic behavior of steel plates. The effects of design parameters, initial deflection and aspect ratio, width-thickness ratio are studied by using FEM analysis. The results obtained from the monotonic loadings show that the aspect ratio(a/b) on the strength is to be neglected in the range of $(a/b){\leq}1.0$. The major cause of the reduction in strength sbbjected to cyclic loadings are width-thickness ratio and displacement amplitude. Based on the results, this paper presents some new strength curve with considering the cyclic deteriorations. The results are also discussed about the deformation capacity accordance with the width-thickness ratio and displacement amplitude.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.237-240
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• 2008

The objective of this study is to evaluate the seismic performance of the low-rise RC apartment buildings having piloties at ground level by using nonlinear static analysis with regards to the maximum considered and design earthquakes in Korea. To do this, the target displacement at roof was estimated according to FEMA356 (or ASCE/SEI-41), and the deformations of the critical members were compared with the failure criteria of Life Safety(LS) and Collapse Prevention(CP) given in FEMA356. The conclusions are as follows: (1) columns satisfy criteria of LS and CP, but (2) the shear wall in the longitudinal direction failed to satisfy those of both LS and CP while those in the transverse direction satisfy that of LS, but failed that of CP.

• Proceedings of the Safety Management and Science Conference
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• 2011.11a
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• pp.75-84
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• 2011

In this paper various numerical analyses are carried out according to behavior characteristics of structures and types of seismic design methods as a study on the seismic analysis for underground structures. Equivalent Static Force Procedure and Response Displacement Method commonly used in practiral design are adopted and Time History Method regarded as the most accurate analysis method is selected to verify the results of two practical methods above. 3-D modelling for seismic analysis of structures is introduced to consider Structure Soil Interaction and all analyses are based on Korea Structural Concrete Design Code. After numerical analyses, Equivalent Static Force Procedure and Response Displacement Method showed relatively lager values than those of Time History Method, so it is identified that above two methods are suitable for practical design purpose.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.2
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• pp.69-80
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• 2008

In this study, improved capacity spectrum method (CSM) is proposed. The method can account for higher mode contribution to the seismic response of MDOF systems. The CSM has been conveniently used for determining maximum roof displacement using both demand spectrum and capacity curve of equivalent SDOF system. Unlike the conventional CSM, the maximum roof displacement is determined without iteration using inelastic displacement ratio and R factor calculated from demand spectrum and capacity curve. Three moment resisting steel frames of 3-, 9- and 20-stories are considered to test the accuracy of the proposed method. Nonlinear response history analysis (NL-RHA) for three frames is also conducted, which is considered as an exact solution. SAC LA 10/50 and 2/50 sets of ground motions are used. Moreover, this study estimates maximum story drift ratios (IDR) using ATC-40 CSM and N2-method and compared with those from the proposed method and NL-RHA. It shows that the proposed CSM estimates the maximum IDR accurately better than the previous methods.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.5 s.39
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• pp.25-33
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• 2004

To evaluate the seismic capacity of a multistorey building structures in performance based seismic design, it is needed to convert MDOF model into equivalent SDOF model. This paper presents predictions for interstory drift of multistorey structures using method of converting a MDOF system into an equivalent SDOF model. The principal objective of this investigation is to evaluate appropriateness of converting method through performing nonlinear time history analysis of a multistory building structures and an equivalent SDOF model. Comparing the interstory drift of multistorey structures calculated by time history analysis and those evaluated by an equivalent SDOF model, the adequacy and the validity of converting method is verified. The conclusion of this study is following; A method of converting a MDOF system into an equivalent SDOF model through the nonlinear time history response analysis is valid. Inelastic first mode shapes are expected to be more accurate than elastic first mode shapes in obtaining interstory drift of multistorey structures from equivalent SDOF model.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.6
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• pp.71-80
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• 2003

Though a nonlinear time history analysis may be provided to estimate more exactly the seismic performance of building structure, approximation methods are still needed in the aspect of practicality and simplicity, In converting a multi-story structure to an equivalent SDOF system, the mode vectors of the multi-story structure are assumed as the mode shape in elastic state regardless of elastic or elastic-plastic state. However, the characteristics of displacement mode are also changed after the yielding made in the structural elements, because the structure becomes inelastic in each incremental load step. In this research, a method of converting MDOF system to ESDOF system is presented by using nonlinear displacement mode considering the mode change of structures after the yielding. Also, the accuracy and efficiency of the method of the nonlinear displacement mode method of the estimate of seismic response of Mixed Building Structures were examined by comparing the displacements of the roof level of the multi-story building structures estimated from this converted displacement response of ESDOF with the displacement of the roof level through the nonlinear dynamic analysis of the multi-story building structures subjected to an actual earthquake excitation.

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.638-649
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• 2020

Purpose: The objective of this study is to evaluate the load carrying capacity of a target bridge structure based on the simple slab bridge of concrete over 20 years of public service. Method: By performing static loading test and dynamic loading test, the displacement, strain, impact factor, and natural frequency values were measured and evaluated through analysis method. Result: The main results of this study are as follows. First, the maximum displacement and maximum strain of S1 were assessed at 2.917 mm and 44.720 𝜇ε( tensile) and -13.760 𝜇ε(compression), respectively, with S2 maximum displacement and maximum strain being 2.100 mm and 4.870 𝜇ε(tensile), respectively. Second, the maximum measured impact factor was 0.191 in section S1 A-A, and the maximum measured impact factor was 0.155 in section S2 C-C. Third, the natural frequency was assessed at 6.086 Hz, and the measurement was found to be within the range of 6.152 Hz to 6.738 Hz. Conclusion: The tested bridge may be evaluated to show good behavior and characteristics for the design load.