• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.82-88
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• 2010

The purpose of this research is a seismic capacity evaluation and strengthening of existing railway station buildings, which were constructed before the seismic design code activated. The seismic capacity of 2nd story RC station building is evaluated by using nonlinear time-history analysis. Analysis results are checked by story drift ratio and story shear, which are described in design code. As a result, the story shears are exceeding the base shear of the design code, the appropriate seismic strengthening methods are needed. To improve the seismic capacity, metallic dampers are used. Evaluation parameters are metallic damper shape and damper installation methods. Dampers are installed in four places in X and Y directions of station buildings. By reviewing of time-history analysis results, the metallic damper, which is installed inverted K-brace type, shows a better seismic performance than other damper shape and installation methods.

• Computational Structural Engineering
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• v.27 no.2
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• pp.26-34
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• 2014

• 전기의세계
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• v.67 no.7
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• pp.30-33
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• 2018

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.108-116
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• 2017

In this study, the prototype structure of seismically designed steel moment frame was analyzed statically and dynamically in order to demonstrate the applicability of energy-based approximate analysis with the dynamic effect of sudden column loss in the evaluation of the collapse resistance and a method for assessing the sensitivity to progressive collapse was proposed. For the purpose of comparing the structural behavior of buildings with different structural systems, the sensitivity of the structure to the sudden removal of vertical members can be used as a significant measure. The energy-based approximate analysis prediction for the prototype structure considered in the study showed good agreement with the dynamic analysis result. In the sensitivity evaluation, the structural robustness index that indicates the ability of a structure to resist collapse induced by abnormal loads was used. It was confirmed that the proposed methods can be used conveniently and rationally in progressive collapse analysis and design.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.74-85
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• 2022

The purpose of this paper is to review the applicability of the current standards for the evaluation method of input variables and performance level in seismic performance evaluation by dynamic plastic analysis of the concrete gravity-type dam to which MCE is applied, and to suggest improvements. To this end, a domestic concrete gravity-type dam was selected as a target facility, dynamic plasticity analysis was performed under various conditions, and applicability to input variables such as concrete tensile strength and breaking energy, was reviewed. By analyzing the effect of cracks at the bottom of the gravity dam on the stability of the activity, an improvement plan for the performance level evaluation method required to secure the water storage function was derived. If the proposed improvement plan is applied, it will have the effect of deriving more reasonable evaluation results than the current seismic performance evaluation method to which MCE is applied.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.35-38
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• 2007

Aiming at time-dependent performance prediction of Liquid Rocket Engine(LRE) system, Modular Program for Conceptual Design of LRE is reviewed, and a modeling and dynamic analysis of rocket engine system with reference to Rocket Engine Dynamic Simulator(REDS) is outlined. Component modeling is based on classical thermodynamic and inviscid theories, and were formulated mathematically in terms of essential parameters. Essential design parameters are addressed. The rocket engine is modeled as a system of pipes with various hydraulic elements, and then the operate characteristic of that elements are simulated by solving conservation equation sequentially.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.5
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• pp.431-438
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• 2012

Non-linear turbojet engine controller with high operational performance has been designed for the high maneuverability UAV. The turbojet engine dynamic performance code has been developed to reflect the non-linear characteristics on controller design, by which the necessity of non-linear controller design was justified by investigating the limitation of linear model derived from the dynamic performance. The PI-like fuzzy controller was designed and enhanced by combining with conventional derivative control. This designed fuzzy controller proves its effectiveness by showing superior control performances over the conventional PID controller along with guaranteeing the safe operation within compressor surge, flame out and turbine temperature limits etc.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.201-204
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• 2004

In this study, the GSP and in-house numerical codes have been used for analyses of the on-design, static off-design and dynamic off-design performances. Through the various missions including altitude, velocity, and power variations static engine performance have been investigated. The dynamic engine performances based on these complicated variations have been also analysed. Especially, the power, engine rpm and heat overload characteristics of a turbine have been estimated with the response time through the control of a throttle setting rather than a power setting. It could be applied to the FADEC system as an engine control device.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.2
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• pp.17-24
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• 2005

In this study, the GSP and in-house numerical codes have been used for analyses of the on-design, static off-design and dynamic off-design performances. Through the various missions including altitude, velocity, and power variations the static engine performance have been investigated. The dynamic engine performances based on these complicated variations have been also analyzed. Especially, the power, engine rpm and heat overload characteristics of the turbine have been estimated with the response time through the control of the throttle setting rather than the power setting. It could be applied to the FADEC system as an engine control device.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.707-717
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• 2006

As an alternative to conventional prestressed concrete (PSC) girders, various types of PSC girders are either under development or have already been applied in bridge structures. Incrementally prestressed concrete girder is one of these newly developed girders. According to the design concept, these new types of PSC girders have the advantages of requiring less self-weight while having the capability of longer spans. However, the dynamic interaction between bridge superstructures and passing trains is one of the critical issues concerning these railway bridges designed with more flexibility. Therefore, it is very important to evaluate modal parameters of newly designed bridges before doing dynamic analyses. In the present paper, a 25 meters long full scale PSC girder was fabricated as a test specimen and modal testing was carried out to evaluate modal parameters including natural frequencies and modal damping ratios at every prestressing stage. During the modal testing, a digitally controlled vibration exciter as well as an impact hammer is applied, in order to obtain precise frequency response functions and the modal parameters are evaluated varying with construction stages. Prestressed force effects on changes of modal parameters are analyzed at every incremental prestressing stage. With the application of reliable properties from modal experiments, estimation of dynamic performances of PSC girder railway bridges can be obtained from various parametric studies on dynamic behavior under the passage of moving train. Dynamic displacements, impact factor, acceleration of the slab, end rotation of the girder, and other important dynamic performance parameters are checked with various speeds of the train.