• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.216-221
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• 2006

This study provides a methodology for development of the Seismic Damage Evaluation System (SDES) in Korea. Major systems and status of database related to road networks in Korea are investigated to analyze the usability of the required information for developing the SDES. In this study, the SDES is composed of four components that are the road network component, the ground motion component, the fragile structure component, and the cost component. In addition, the procedures for the construction of database which support the SDES is proposed, and a prototype of the SDES for expressway of Korea is developed based on the developed methodology. The National Geospatial Information System (NGIS) and the National Earthquake Information System (NEIS) are used to develop the road network component and ground motion component, respectively. For the fragile structure component and the cost component, Highway Bridge Management System (HEMS) was used.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.184-191
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• 1997

A method, termed as the substructural sensitivity synthesis method, which utilizes the computational merits of the component mode synthesis technique is proposed to calculate design sensitivity of modal parameters of substructurally combined structures. In this method, the sensitivity analysis is combined with component mode synthesis thchnique. thus the degrees of freedom of a combined structure can be dramatically reduced. Free-interface mode method including the residual attachment modes among the component mode synthesis methods is used to calculate the modal sensitivity of the combined structure. For the design sensitivities of modal properties of structure, the Nelson's method, which is exact solving method is used. It is shown that the modal sensitivities of the entire structure can be obtained by synthesizing the substructural modal data, and the sensitivities of the modal data about the design variables of modifiable substructure. Using the proposed method, the final degrees of freedom of entire structure can be remarkably reduced to calculate the modal parameter sensitivities. With a structure composed of beams and plates, as an example, the sensitivities of the eigenvalues and eigenvectors obtained by this proposed method were compared with the exact solutions in terms of accuracy.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.585-590
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• 1995

This paper describes strain distribution analysis of a multiple parallel plate structure for a multi-componenet force and moment sensor. A parallel plate structure which has higher rigidity than a simple beam structure are widely used for multi-component force and moment sensor. The strain distribution in the beams of a parallel plate structure should be accurately calculated to design a high precision multi-component force and moment sensor. We derived equations to calculate the strains for multiple parallel plate structure. It reveals that results from finite element analysis and experiment are in good agreement with results from the derived equations.

• 대한안전경영과학회지
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• 제14권1호
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• pp.225-233
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• 2012

The research discusses interrelationship of structural and reliability importance measures which used in the probabilistic safety assessment. The most frequently used component importance measures, such as Birnbaum's Importance (BI), Risk Reduction (RR), Risk Reduction Worth (RRW), RA (Risk Achievement), Risk Achievement Worth (RAW), Fussel Vesely (FV) and Critically Importance (CI) can be derived from two structure importance measures that are developed based on the size and the number of Minimal Path Set (MPS) and Minimal Cut Set (MCS). In order to show an effectiveness of importance measures which is developed in this paper, the three representative functional structures, such as series-parallel, k out of n and bridge are used to compare with Birnbaum's Importance measure. In addition, the study presents the implementation examples of Total Productive Maintenance (TPM) metrics and alternating renewal process models with exponential distribution to calculate the availability and unavailability of component facility for improving system performances. System state structure functions in terms of component states can be converted into the system availability (unavailability) functions by substituting the component reliabilities (unavailabilities) for the component states. The applicable examples are presented in order to help the understanding of practitioners.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.2974-2988
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• 2022

Implementation of component isolation in nuclear industry is challenging due to gaps in research and the lack of specific guidelines. In this study, parameters affecting component-level isolation of advanced reactor vessels are identified based on a representative numerical model with explicit consideration of nonlinear soil-structure interaction (SSI). The objective of this study is to evaluate the effectiveness of, and to identify potential limitations of using conventional friction pendulum bearings to seismically isolate vessels. It is found that slender vessels or components are particularly vulnerable to rotational accelerations at the isolation interface, which are caused by rotation of the sub-structure and by excitation of higher modes in the horizontal direction of the seismically isolated system. Component isolation is found to be more effective for relatively stiffer vessels and at sites with stiff soil. Considering that conventional isolators are deficient in resisting axial tension, it is observed that the optimum location for supporting a component to achieve seismic isolation, is at a cross-sectional plane passing through the center of mass of the vessel. These findings are corroborated by numerous simulations of the response of seismically isolated reactor vessels at different nuclear power plant sites subject to a variety of ground motions.

• IEIE Transactions on Smart Processing and Computing
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• 제5권3호
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• pp.222-229
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• 2016

Linked Data is a powerful technology for storing and publishing the structures of data. It is helpful for web applications because of its usefulness through semantic query data. However, using Linked Data is not easy for ordinary users who lack knowledge about the structure of data or the query syntax of Linked Data. For that problem, we propose a translator component that is used for translating RESTful/JSON request messages into SPARQL commands based on ontology - a metadata that describes the structure of data. Clients do not need to worry about the structure of stored data or SPARQL, a kind of query language used for querying linked data that not many people know, when they insert a new instance or query for all instances of any specific class with those complex structure data. In addition, the translator component has the search function that can find a set of data from multiple classes based on finding the shortest paths between the target classes - the original set that user provide, and target classes- the users want to get. This translator component will be applied for any dynamic ontological structure as well as automatically generate a SPARQL command based on users' request message.

• 센서학회지
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• 제23권2호
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• pp.105-109
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• 2014

Structure and electrical properties of $0.85NaNbO_3-0.15LiNbO_3$ ($(Li_{0.15}Na_{0.85})NbO_3$) ceramics were investigated as a function of sintering temperature. $(Li_{0.15}Na_{0.85})NbO_3$ ceramics were prepared by conventional solid state processing. A main phase of the orthorhombic perovskite structure and secondary phase of $LiNbO_3$ were confirmed for all sintered specimens. Dense $(Li_{0.15}Na_{0.85})NbO_3$ ceramics were obtained at sintering temperature above $1050^{\circ}C$. With increasing sintering temperature, the electromechanical coupling factor ($k_p$), piezoelectric constant ($d_{33}$) and relative dielectric constant (${\varepsilon}_r$) of the sintered specimens increased, while the mechanical quality factor ($Q_m$) decreased. These results are due to the increase of grain size and crystallite size of orthorhombic perovskite structure. Based on the temperature dependence of ${\varepsilon}_r$, stable piezoelectric properties were expected because no phase transition found up to $300^{\circ}C$. Typically, kp of 18%, $d_{33}$ of 34.7 pC/N, ${\varepsilon}_r$ of 135, and $Q_m$ of 62.8 were obtained for the specimens sintered at $1200^{\circ}C$ for 5 h.

• 한국지진공학회논문집
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• 제26권3호
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• pp.105-116
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• 2022

Seismic demand on nonstructural components (NSCs) is highly dependent on the coupled behavior of a combined supporting structure-NSC system. Because of the inherent complexities of the problem, many of the affecting factors are inevitably neglected or simplified based on engineering judgments in current seismic design codes. However, a systematic analysis of the key affecting factors should establish reasonable seismic design provisions for NSCs. In this study, an idealized 2-DOF model simulating the coupled structure-NSC system was constructed to analyze the parameters that affect the response of NSCs comprehensively. The analyses were conducted to evaluate the effects of structure-NSC mass ratio, structure, and NSC nonlinearities on the peak component acceleration. Also, the appropriateness of component ductility factor (R_p) given by current codes was discussed based on the required ductility capacity of NSCs. It was observed that the responses of NSCs on the coupled system were significantly affected by the mass ratio, resulting in lower accelerations than the floor spectrum-based response, which neglected the interaction effects. Also, the component amplification factor (a_p) in current provisions tended to underestimate the dynamic amplification of NSCs with a mass ratio of less than 15%. The nonlinearity of NSCs decreased the component responses. In some cases, the code-specified R_p caused nonlinear deformation far beyond the ductility capacity of NSCs, and a practically unacceptable level of ductility was required for short-period NSCs to achieve the assigned amount of response reduction.

• 대한기계학회논문집A
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• 제29권5호
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• pp.716-725
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• 2005

The method of substructure synthesis o. component mode synthesis(CMS) provides an effective means of dynamic analysis of very large and/or complex structures. In this study, residual dynamic flexibility attachment modes in hybrid component mode synthesis are considered for the purpose of exactly compensating the effect of higher order truncated modes. Following this way, the analysis accuracy of the synthesized structure can be improved effectively with less computational effort. In order to show the accuracy and effectiveness of the proposed hybrid component mode synthesis(HCMS), numerical experiments were carried out for the models of a clamped-clamped beam. The results verified the effectiveness of the proposed method.

• Computational Structural Engineering : An International Journal
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• 제1권1호
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• pp.71-80
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• 2001

A reliability approach to evaluate structural performance has gained increased acceptability and usage over the past two decades. Most reliability analyses are based on the reliability of an individual component without examining the entire structural system. These analyses often result in either unnecessary repairs or unsafe structures. This study uses examples of series, parallel, and series-parallel models of structural systems to illustrate how the component reliabilities affect the reliability of the entire system. The component-system reliability interaction can be used to develop optimum lifetime inspection and repair strategies for structural systems. These examples demonstrate that such strategies must be based on the reliability of the entire structural system. They also demonstrate that the location of an individual component in the system has a profound effect on the acceptable reliability of that component. Furthermore, when a structure is deteriorating over time, the reliability importance of various components is a1so changing with time. For this reason, the most critical component in the early life of the structure may not tie the most critical later.