• Smart Structures and Systems
• /
• 제20권2호
• /
• pp.139-150
• /
• 2017

The structural strain plays a significant role in structural condition assessment of in-service bridges in terms of structural bearing capacity, structural reliability level and entire safety redundancy. Therefore, it has been one of the most important parameters concerned by researchers and engineers engaged in structural health monitoring (SHM) practices. In this paper, an SHM system instrumented on the Jiubao Bridge located in Hangzhou, China is firstly introduced. This system involves nine subsystems and has been continuously operated for five years since 2012. As part of the SHM system, a total of 166 fiber Bragg grating (FBG) strain sensors are installed on the bridge to measure the dynamic strain responses of key structural components. Based on the strain monitoring data acquired in recent two years, the strain-based structural condition assessment of the Jiubao Bridge is carried out. The wavelet multi-resolution algorithm is applied to separate the temperature effect from the raw strain data. The obtained strain data under the normal traffic and wind condition and under the typhoon condition are examined for structural safety evaluation. The structural condition rating of the bridge in accordance with the AASHTO specification for condition evaluation and load and resistance factor rating of highway bridges is performed by use of the processed strain data in combination with finite element analysis. The analysis framework presented in this study can be used as a reference for facilitating the assessment, inspection and maintenance activities of in-service bridges instrumented with long-term SHM system.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
• /
• pp.390-397
• /
• 1998

An approach to identifying input forces is proposed using measured structural dynamic responses and its analytical model. The identification of input forces is a reverse process and ill-conditioned problem. Its solution is unstable and generally case dependent. In this paper, the ill-condition is described considering characteristic matrix which is defined by reduced dynamic stiffness matrix. Special attention is focused on the condition number of a characteristic matrix used in the solution algorithm of this reverse process. Simple example is presented in support of the ill-condition of a reverse process.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2004년도 추계학술대회 논문집
• /
• pp.73-77
• /
• 2004

This study is object to design and structural analysis of Long Pull weight machine. Structural analysis of Long Pull weight machine using result from ANSYS code. This structural analysis results, many variables such as boundary condition, constraints and load condition were considered.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2002년도 추계학술대회 논문집
• /
• pp.69-74
• /
• 2002

This study is object to structural analysis of high pressure injection nozzle. The finite element model was developed to compute the stress, strain for high pressure injection nozzle. For structural analysis using result from FEM code. This structural analysis results, many variables such as internal pressure, boundary condition, constraint condition and load condition are considered.

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2000년도 추계학술대회
• /
• pp.87-92
• /
• 2000

This study is object to structural analysis of running machine frame. The finite element model was developed to compute the stress, strain and natural frequency for running machine frame. For structural analysis using result from FEM Code. In other to structural analysis of running machine frame, many variables such as load condition, boundary condition and weight condition are considered.

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2001년도 추계산학기술 심포지엄 및 학술대회 발표논문집
• /
• pp.85-90
• /
• 2001

This study is object to structural analysis of household running machine frame. The finite element model was developed to compute the stress, strain and natural frequency for household running machine frame. For structural analysis using result from FEM Code. In other to structural analysis of household running machine frame, many variables such as load condition, boundary condition and weight condition are considered.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
• /
• pp.61-68
• /
• 1998

It has become important to evaluate the qualitive reliability and condition assessment of existing structural systems in order to establish a rational program for repair and maintenance. Since most of if existing structural system may suffer from defect corrosion and damage, it is necessary to account for their effects in fuzzy reliability analysis, In this paper, an attempt is made to develope a reliability analysis for damaged structural systems using failure possibility theory. Damage state is specified in terms of linguistic valiables using natural language information and numerical information, which are defined by fuzzy sets. Using a subjective condition index of failure possibility and information of the damage state is introduced into the calculation of failure probability. The subjective condition index of quantitative and qualitative analysis method is newly proposed based on the fuzzy set operations, namely logical product, drastic product, logical sum and drastic sum

• 대한원격탐사학회지
• /
• 제39권5_1호
• /
• pp.621-635
• /
• 2023

시설물 상태평가는 시설물의 사용성을 평가하고, 진단 주기를 결정하는 중요한 과정이다. 현재 수행되고 있는 인력 기반 방법은 안전, 효율, 객관성에 대한 문제를 안고 있어 이를 개선하기 위해 영상을 이용한 딥러닝(deep learning) 기반의 연구가 수행되고 있다. 그러나 시설물 손상 데이터는 발견하기 어려워 다량의 시설물 손상 학습 데이터를 구축하기 어렵고, 이는 딥러닝 기반 상태평가에 한계로 작용한다. 본 연구에서는 영상 기반 시설물 상태평가의 학습 데이터 부족으로 인한 어려움을 개선하기 위해 파운데이션 모델(foundation model) 기반 2-step 시설물 손상 분석을 제시한다. 시설물 상태평가의 요소를 객체화와 정량화로 세분화하고, 정량화 단계에서 영상 분할(segmentation) 파운데이션 모델을 적용하였다. 본 연구의 방법은 기존 영상 분할 방법 대비 10% 포인트 이상 높은 mean intersection over union을 나타냈고, 특히 철근 노출의 경우에는 40% 포인트 이상의 성능 개선을 보였다. 본 연구의 방법이 학습 데이터 구축이 어려운 도메인에 성능 개선을 가져올 것이라 기대한다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
• /
• pp.805-810
• /
• 2000

The purpose of this study is to predict long-term structural safety on the Yonggwang Unit 3 prestressed concrete containment building. The aging-related degradations of its main structural materials are investigated and the effects of the property variation of time-dependent materials on the structural behavior of containment building are also assessed through the analysis on the ultimate pressure capacity. The nonlinear finite element analyses for both the design criteria condition a the present aging condition are conducted to assess the present structural capacity of the containment building As a result, it is verified that the structural capacity of the Yonggwang Unit 3 containment building under the present aging condition is judged to be still rugged. n addition, the sensitivity of the ultimate pressrue capacity of containment building according to th degradation levels of the structural materials are assessed. Finally, it is showed that the sensitivity levels are in the order of the tendon, rebar and concrete in case of individual material degradations, and the tendon-rebar, tendon-concrete and rebar-concrete in case of coupled material degradations.

• 한국공작기계학회논문집
• /
• 제10권4호
• /
• pp.104-110
• /
• 2001

The objective of this study is structural analysis of continuous casting mold. A two-dimensional finite element model was developed to compute the temperature distribution, thermal stress and thermal strain behavior for continuous casting mold. Structural analysis was made using thermal analysis result, utilizing transient analysis of ANSYS. This structural analysis results, many variables such as casting speed, cooling condition film coefficient, convection and load condition are considered.