• 한국안전학회지
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• 제21권2호
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• pp.80-88
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• 2006

In the present study damage behavior of resilient sleepers on concrete ballasts is analyzed. Cracks of resilient sleepers in a railway track system are concentrated on inside of blocks to which the tie bars are connected. Finite element analysis is performed by dividing a block into the straight section and the curved section according to the load condition of the resilient sleeper, and limited the interpretation within the range of resilience. In addition, the value of stress obtained from the interpretation was compared with the allowable stress of concrete to determine the safety. According to the result of numerical analysis, compared with the stress before unequal settlement, the tensile stress of the inside of the block increased significantly after the settlement considering the entire block, and the tensile stress of this part exceeded the allowable stress of concrete, so was undesirable in terms of safety. In reality, the arrangement of tensile stiffeners inside blocks connected to tie bars is improper in the design of resilient sleepers, and when unequal settlement occurs, tensile stress increases on this part and consequently causes cracking damage. It is necessary to arrange wire meshes or tensile reinforcing bars in a structurally safe way to reinforce the inside of blocks on which cracks are concentrated.

• 제어로봇시스템학회논문지
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• 제17권11호
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• pp.1082-1089
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• 2011

Most engineered systems are designed with high levels of system redundancies to satisfy required reliability requirements under adverse events, resulting in high systems' LCCs (Life-Cycle Costs). Recent years have seen a surge of interest and tremendous advance in PHM (Prognostics and Health Management) methods that detect, diagnose, and predict the effects of adverse events. The PHM methods enable proactive maintenance decisions, giving rise to adaptive reliability. In this paper, we present a RAP (Resilience Allocation Problem) whose goal is to allocate reliability and PHM efficiency to components in an engineering context. The optimally allocated reliability and PHM efficiency levels serve as the design specifications for the system RBDO (Reliability-Based Design Optimization) and the system PHM design, which can be used to derive the detailed design of components and PHM units. The RAP is demonstrated using a simplified aircraft control actuator design problem resulting in a highly resilient actuator with optimally allocated reliability, PHM efficiency and redundancy for the given parameter settings.

• 한국가스학회지
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• 제17권4호
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• pp.77-82
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• 2013

LNG의 수요 증가와 함께 LNG기지의 저장탱크의 건설도 증가하고 있다. 내부탱크는 9%Ni강재 그리고 외부탱크는 콘크리트가 적용되는 형식의 LNG탱크의 단열은 내외부 탱크 사이에 펄라이트 분말이 충전되며, 이 펄라이트의 압력을 흡수하기 위하여 탄성이 있는 블랭킷을 사용한다. 본 연구에서는 이 블랭킷을 적용함에 있어 그 특성과 내부 탱크에 미치는 압력 등을 해석, 고찰하여 블랭킷의 적정 설계두께, 설계압력 등 설계기준을 얻고자 하였다. 연구결과, 블랭킷의 적정 두께설계 기준은 내외부 탱크 간격의 30~40%가 되었으며, 설계압력 기준은 블랭킷 두께에 따라 2,200~2,700Pa 이하가 적절한 것으로 얻어졌다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.182-186
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• 2006

An efficient dynamic response analysis mettled of structures supported by resilient mounts is presented by using the structural synthesis method in frequency domain and time domain. As a numerical example, a mount-deck system is considered. Through numerical simulations, the validity of the presented method is verified by comparison of the results with those of the 'traditional' analysis method.

• Journal of information and communication convergence engineering
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• 제19권3호
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• pp.175-179
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• 2021

Enhancing the reliability of the system is important for recent system-on-chip (SoC) designs. This importance has led to studies on fault diagnosis and tolerance. Fault-injection (FI) techniques are widely used to measure the fault-tolerance capabilities of resilient systems. FI techniques suffer from limitations in relation to environmental conditions and system features. Moreover, a hardware-based FI can cause permanent damage to the target system, because the actual circuit cannot be restored. Accordingly, we propose a simulation-based FI framework based on the Verilog Procedural Interface for measuring the failure rates of SoCs caused by soft errors. We execute five benchmark programs using an ARM Cortex M0 processor and inject soft errors using the proposed framework. The experiment has a 95% confidence level with a ±2.53% error, and confirms the reliability and feasibility of using proposed framework for fault analysis in SoCs.

• Structural Engineering and Mechanics
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• 제76권1호
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• pp.57-65
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• 2020

It is very important to allocate valuable resources efficiently when reconstructing buildings after earthquake damage. This paper proposes the use of a simple seismic retrofitting system to make buildings more resilient than the stiffer systems such as the shear walls implemented in Chile after the earthquake in 2010. The proposal is based on the use of steel chevron-type braces in RC buildings as a dual system to improve the seismic performance of multistory buildings. A case study was carried out to compare the proposal with the shear wall solution for the typical seismic Chilean RC building from the structural and economic perspectives. The results show that it is more resilient than other stiffer seismic solutions, such as shear walls, reduces the demand, minimizes seismic damage, gives reliable earthquake protection and facilitates future upgrades and repairs while achieving the level of immediate occupancy without the costs of the shear walls system.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.587-598
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• 2008

In the trackbed design using elastic multi-layer model, the stress-dependent resilient modulus is an important input parameter, which reflects substructure performance under repeated traffic loading. The resilient moduli of crushed stone and weathered granite soil were developed using nonlinear dynamic stiffness, which can be measured by in-situ and laboratory seismic tests. The prediction models of resilient modulus varying with the deviatoric or bulk stress were proposed (Park et al., 2008). To investigate the performance of the prediction models proposed herein, the elastic response of the test trackbed near PyeongTaek, Korea was evaluated using a 3-D nonlinear elastic computer program (GEOTRACK) and compared with measured elastic vertical displacement during the passages of freight and passenger trains. The material types of the test sub-ballasts are crushed stone and weathered granite soil, respectively. The calculated vertical displacements within the sub-ballasts are within the order of 1mm, and agree well with measured values with the reasonable margin. The prediction models are thus concluded to work properly in the preliminary investigation. The prediction models proposed for resilient modulus were verified by the comparison of the calculated vertical displacements with measured ones during train passages.

• 대한토목학회논문집
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• 제12권3호
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• pp.215-220
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• 1992

최근 선진 외국은 MR을 적용한 합리적인 포장해석-설계법의 이용을 확대해 나가고 있으며 각 국의 고유한 포장재료에 대한 신뢰성있는 시험방법 및 MR특성에 관한 연구들이 활발히 수행되고 있다. 따라서 국내 포장재료에 대한 MR특성 연구는 매우 중요하며, 특히 대단위 국토건설과 함께 골재난에 직면하고 있는 우리의 실정으로 보아 석탄화력발전소의 산업폐기물인 석탄회를 포장재료로 활용하기 위한 석탄회의 MR특성 연구는 매우 의의 깊은 일이다. 본 연구는 석탄회를 건설재로서의 대량 활용을 위하여 국내 5개 화력발전소에서 부산되고 있는 저희와 비회 그리고 중부지역의 4개 화강토를 연구 대상으로 하여, AASHTO 시험법에 의한 MR특성을 규명하고 MR-CBR상관관계를 규명한 것이다.

• 한국도로학회논문집
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• 제9권1호
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• pp.47-56
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• 2007

교통하중하의 포장구조에 대한 설계나 비선형 해석에 있어 도로하부 재료의 회복변형 특성이 활용되고 있다. 그러나 국내에서의 관련 연구가 매우 미진한 실정이다. 또한 매우 제한적인 범위의 자료만이 노상토의 회복탄성계수를 추정하는데 활용되고 있다. 이에 본 논문에서는 시험도로 입상 노상토를 대상으로 비선형 특성을 알아보기 위하여 반복재하 회복탄성계수 시험을 수행하였다. 현장조건을 반영하여 함수비와 응력조건을 고려한 회복탄성계수 구성방정식을 제안하였다. 이를 통하여 응력조건을 고려한 회복탄성계수 예측모델과 적합한 응력의존 모델을 결정하고 계절적인 함수비 변화가 고려된 회복탄성계수 모델을 각각 비교하였다.

• 한국철도학회논문집
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• 제11권1호
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• pp.54-60
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• 2008

다층 탄성모델에 근거한 철도노반 설계는 열차의 반복 윤하중에 의한 궤도 하부 구조의 거동을 반영하는 응력 의존적인 회복탄성계수$(E_R)$가 각 층의 중요한 입력물성치가 된다. 그러나 반복하중을 가하는 기존의 회복탄성계수 시험법은 비용이 고가이고 시험장비와 숙련도에 따라 결과의 일관성이 떨어지는 단점이 있어 실질적인 적용에 어려움이이었다. 본 연구에서는 이를 극복하기 위해 동적물성치를 이용한 대체 회복탄성계수 시험법을 적용하여 철도노반의 회복탄성계수를 결정하였다. 강화노반에 주로 사용되는 쇄석의 회복탄성계수는 측정된 동적물성치와 열차 운행 중 경험하는 강화노반의 응력을 고려하여 결정되었고, 체적응력과 축차응력의 거듭제곱 형태로 예측모델을 나타내었다. 쇄석의 회복탄성계수는 체적응력이 증가함에 따라 전체적으로 증가하는 경향을 보였고 축차응력이 증감함에 따라 감소하였다. 상 하부노반의 주재료인 SM계열 토사 재료에 대하여 회복탄성계수를 평가하였고, 축차응력만을 이용한 거듭제곱 형태의 예측모델과 상관성이 매우 높게 나타났다.