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장대교량의 건전도 모니터링을 위한 FE 모델 개선 기법의 연구
허광희(Heo Gwanghee),이진옥(Lee Chin Ok),전준룡(Jeon Joonryong),이규(Lee Giu) 한국구조물진단유지관리학회 2005 한국구조물진단학회 학술발표회논문집 Vol.- No.-
This paper proposes an effective finite element model updating method for steel plate girder bridges subjected ambient vibration excitations such as winds and traffic loads. Updating FE model is necessary to secure structural integrity for health monitoring, and is made possible by using the correlation between the experimental and analytical results. In this research, experimental testing adopts ambient vibration under normal traffic loads because forced vibration is inappropriate for long-term measuring and real-time monitoring. For our FE analysis, a 3-dimensional model with beam and shell element is employed for precision. Also, updating involves direct matrix and error matrix method to increase applicability. The efficiency of the proposed FE model updating method is evaluated by MAC(Modal assurance criteria) value and difference of natural frequencies each before and after updating. All such comparisons prove the effectiveness of FE model updating for structural health monitoring using ambient vibration. Therefore, the updating techniques proposed in this paper prove to be applicable in the real structure by applying the ambient vibration techniques under the normal traffic loads.
장대교량의 건전도 모니터링을 위한 FE 모델 개선 기법의 연구
허광희 ( Heo Gwanghee ),이진옥 ( Lee Chin Ok ),전준룡 ( Jeon Joonryong ),이규 ( Lee Giu ) 한국구조물진단유지관리공학회 2005 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.9 No.1
This paper proposes an effective unite element model updating method for steel plate girder bridges subjected ambient vibration excitations such as winds and traffic loads. Updating FE model is necessary to secure structural integrity for heath monitoring, and is made possible by using the correlation between the experimental and analytical results. In this research, experimental testing adopts ambient vibration under normal traffic loads because forced vibration is inappropriate for long-term measuring and real-time monitoring. For our FE analysis, a 3-dimensional model with beam and shell element is employed for precision. Also, updating involves direct matrix and error matrix method to increase applicability. The efficiency of the proposed FE model updating method is evaluated by MAC(Modal assurance criteria) value and difference of natural frequencies each before and after updating. All such comparisons prove the effectiveness of FE model updating for structural health monitoring using ambient vibration. Therefore, the updating techniques proposed in this paper prove to be applicable in the real structure by applying the ambient vibration techniques under the normal traffic loads.
허광희 ( Heo Gwanghee ),이우상 ( Lee Woosang ),이규 ( Lee Giu ),서동환 ( Seo Dongwhan ),전준룡 ( Jeon Joonryong ),박병철 ( Park Byungcheol ) 한국구조물진단유지관리공학회 2004 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.8 No.2
This paper attempts to compute the coefficients of subgrade reaction from which the supporting capacity of piers can be estimated, using dynamic responses of energy applied to the vertical axis of piers in order to evaluate the safety of piers. To compute the coefficients of subgrade reaction, we built up a standard pier, using elastic springs already known which would represent a real condition of ground. We also induced a general relation expression between coefficients of subgrade reaction and eigen value, from numerical formula. After experiments regarding to dynamic responsive properties of a real standard pier, coefficients of subgrade reaction were computed by substituting dynamic properties for the general relation expression. Comparing those results and experimental data, we proved the usefulness of the general relation expression induced in this study.
허광희(Heo Gwanghee),이우상(Lee Woosang),이규(Lee Giu),서동환(Seo Dongwhan),전준룡(Jeon Joonryong),박병철(Park Byungcheol) 한국구조물진단유지관리학회 2004 한국구조물진단학회 학술발표회논문집 Vol.- No.-
This paper attempts to compute the coefficients of subgrade reaction from which the supporting capacity of piers can be estimated, using dynamic responses of energy applied to the vertical axis of piers In order to evaluate the safety of piers To compute the coefficients of subgrade reaction, we built up a standard pier, using elastic springs already known which would represent a real condition of ground We also induced a general relation expression between coefficients of subgrade reaction and eigen value, from numerical formula. After experiments regarding to dynamic responsive properties of a real standard pier, coefficients of subgrade reaction were computed by substituting dynamic properties for the general relation expression. Comparing those results and experimental data, we proved the usefulness of the general relation expression induced in this study
이동기 ( Lee Dong-gi ),이우상 ( Lee Woosang ),이규 ( Lee Giu ),허광희 ( Heo Gwanghee ),전준룡 ( Jeon Joonryong ) 한국구조물진단유지관리공학회 2003 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.7 No.1
In this paper, design and analysis of robust feedback control system are presented using the state-space approach. When mathematical models are used to describe real structural system, the differences between the mathematical models and the real structures can cause poor performance of control systems, especially for large-scale structures due to the structural uncertainties. Therefore, when controllers are used to reduce the random vibration caused by rain and wind loads, we cannot expect that control systems achieve satisfactory control result. Hence, it is important that robust feedback control systems must be designed considering system uncertainties. Considering the robust feedback control to carry out the control of uncertain systems, system stability can be guaranteed for structural perturbations occurring by modeling error. In order to explore the system stability with perturbation, the stability of nominal system should be stable. For application, the uncertain systems considering natural frequency and design constraints i.e, structures that have structural perturbations happening by mass and stiffness, are adapted to develop unified controller algorithm, which is optimal and robust. And, to investigate the validity and performance of the algorithm, numerical simulation is illustrated. Numerical result shows that the designed controller can be applied very well to the problem of degradation of control system performance.
이동기(Lee Dong-Gi),이우상(Lee Woosang),이규(Lee Giu),허광희(Heo Gwanghee),전준룡(Jeon Joonryong) 한국구조물진단유지관리학회 2003 한국구조물진단학회 학술발표회논문집 Vol.- No.-
In this paper, design and analysis of robust feedback control system are presented using the state-space approach. When mathematical models are used to describe real structural system, the differences between the mathematical models and the real structures can cause poor performance of control systems, especially for large-scale structures due to the structural uncertainties. Therefore, when controllers are used to reduce the random vibration caused by rain and wind loads, we cannot expect that control systems achieve satisfactory control result. Hence, it is important that robust feedback control systems must be designed considering system uncertainties. Considering the robust feedback control to carry out the control of uncertain systems, system stability can be guaranteed for structural perturbations occurring by modeling error. In order to explore the system stability with perturbation, the stability of nominal system should be stable. For application, the uncertain systems considering natural frequency and design constraints i.e, structures that have structural perturbations happening by mass and stiffness, are adapted to develop unified controller algorithm, which is optimal and robust. And, to investigate the validity and performance of the algorithm, numerical simulation is illustrated. Numerical result shows that the designed controller can be applied very well to the problem of degradation of control system performance.
탄성고무매트를 이용한 교각의 지반반력계수와 동특성치의 상관관계 분석
허광희(Heo Gwanghee),이진옥(Lee Chin Ok),서동환(Sea Donghwan),이우상(Lee Woosang),전준룡(Jeon Joonryong) 한국구조물진단유지관리학회 2005 한국구조물진단학회 학술발표회논문집 Vol.- No.-
The purpose of this paper is to make sure the equation which was found from the prior study is correct, by choosing an elastic rubber mat from the model pier through consideration of actual stiffness with the similarity of stiffness rate. In order to accomplish this task. The elastic coefficient of elastic rubber mat used average value through compression experiment. By applying achieved ground stiffness, we've performed dynamic property response experiment, then achieved dynamic property value. we've compared and analyzed the calculated value by the equation of ground stiffness from the prior study, with the value that achieved in this paper. The analysed result achieved a difference within 10 percent which is quite satisfactory. The result like this, leads to a decision that has no problem to maintain the structure by applying the 10 percent difference for safety assesment when generally considering the structure. Therefore we've once again verified the efficiency of method which used the computation of coefficient of subgrade reaction equation for safety assesment of pier.
탄성 고무매트를 이용한 교각의 지반반력계수와 동특성치의 상관관계 분석
허광희 ( Heo Gwanghee ),이진옥 ( Lee Chin Ok ),서동환 ( Seo Donghwan ),이우상 ( Lee Woosang ),전준룡 ( Jeon Joonryong ) 한국구조물진단유지관리공학회 2005 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.9 No.1
The purpose of this paper is to make sure the equation which was found from the prior study is correct, by choosing an elastic rubber mat from the model pier through consideration of actual stiffness with the similarity of stiffness rate. In order to accomplish this task, The elastic coefficient of elastic rubber mat used average value through compression experiment. By applying achieved ground stiffness, we've performed dynamic property response experiment, then achieved dynamic property value, we've compared and analyzed the calculated value by the equation of ground stiffness from the prior study, with the value that achieved in this paper. The analysed result achieved a difference within 10 percent which is quite satisfactory. The result like this, leads to a decision that has no problem to maintain the structure by applying the 10 percent difference for safety assesment when generally considering the structure. Therefore we've once again verified the efficiency of method which used the computation of coefficient of subgrade reaction equation for safety assesment of pier.