A multi-functional cable-damper system for vibration mitigation, tension estimation and energy harvesting

정형조,김인호,Jeong-Hoi Koo 국제구조공학회 2011 Smart Structures and Systems, An International Jou Vol.7 No.5

This paper presents a multi-functional system, consisting of a magnetorheological (MR) damper and an electromagnetic induction (EMI) device, and its applications in stay cables. The proposed system is capable of offering multiple functions: (1) mitigating excessive vibrations of cables, (2) estimating cable tension, and (3) harvesting energy for wireless sensors used health monitoring of cable-stayed bridges. In the proposed system, the EMI device, consisting of permanent magnets and a solenoid coil, can converts vibration energy into electrical energy (i.e., induced emf); hence, it acts as an energy harvesting system. Moreover, the cable tension can be estimated by using the emf signals obtained from the EMI device. In addition, the MR damper, whose damping property is controlled by the harvested energy from the EMI device, can effectively reduce excessive cable vibrations. In this study, the multi-functionality of the proposed system is experimentally evaluated by conducting a shaking table test as well as a full-scale stay cable in a laboratory setting. In the shaking table experiment, the energy harvesting capability of the EMI device for wireless sensor nodes is investigated. The performance on the cable tension estimation and the vibration mitigation are evaluated using the full-scale cable test setup. The test results show that the proposed system can sufficiently generate and store the electricity for operating a wireless sensor node twice per day, significantly alleviate vibration of a stay cable (by providing about 20% larger damping compared to the passive optimal case), and estimate the cable tension accurately within a 2.5% error.

A multi-functional cable-damper system for vibration mitigation, tension estimation and energy harvesting

Jung, Hyung-Jo,Kim, In-Ho,Koo, Jeong-Hoi Techno-Press 2011 Smart Structures and Systems, An International Jou Vol.7 No.5

This paper presents a multi-functional system, consisting of a magnetorheological (MR) damper and an electromagnetic induction (EMI) device, and its applications in stay cables. The proposed system is capable of offering multiple functions: (1) mitigating excessive vibrations of cables, (2) estimating cable tension, and (3) harvesting energy for wireless sensors used health monitoring of cable-stayed bridges. In the proposed system, the EMI device, consisting of permanent magnets and a solenoid coil, can converts vibration energy into electrical energy (i.e., induced emf); hence, it acts as an energy harvesting system. Moreover, the cable tension can be estimated by using the emf signals obtained from the EMI device. In addition, the MR damper, whose damping property is controlled by the harvested energy from the EMI device, can effectively reduce excessive cable vibrations. In this study, the multi-functionality of the proposed system is experimentally evaluated by conducting a shaking table test as well as a full-scale stay cable in a laboratory setting. In the shaking table experiment, the energy harvesting capability of the EMI device for wireless sensor nodes is investigated. The performance on the cable tension estimation and the vibration mitigation are evaluated using the full-scale cable test setup. The test results show that the proposed system can sufficiently generate and store the electricity for operating a wireless sensor node twice per day, significantly alleviate vibration of a stay cable (by providing about 20% larger damping compared to the passive optimal case), and estimate the cable tension accurately within a 2.5% error.

불연속체 동해석 기법을 이용한 발파진동 영향평가

박병기(Park, Byung-Ki),전석원(Jeon, Seokwon),박광준(Park, Gwang-Jun),도덕수(Do, Deog-Soo),김태훈(Kim, Tae-Hoon),정두섭(Jung, Du-Seop) 한국소음진동공학회 2005 한국소음진동공학회 논문집 Vol.15 No.12

Since blast-induced vibration may cause serious problem to the rock mass as well as the nearby structures, the prediction of blast-induced nitration and the stability evaluation must be performed before blasting activities. Dynamic analysis has been increased recently in order to analyze the effect of the blast-Induced vibration. Most of the previous studies, however, were based on the continuum analysis unable to consider rock joints which significantly affect the wave propagation and attenuation characteristics. They also adopted pressure corves estimated tv theoretical or empirical equations as input detonation load, thus there were very difficult to reflect the characteristics of propagating media. In this study, therefore, we suggested a dynamic distinct element analysis technique which uses velocity waveform obtained from a test blast as an input detonation load. A distinct element program, UDEC was used to consider the effect of rock joints. In order to verify the validity of proposed method, the test blast was simulated. The predicted results from the proposed method showed a good agreement with the measured vibration data from the test blast. Through the dynamic numerical modelling on the planned road tunnel and slope, we evaluated the effect of blast-induced nitration and the stability of rock slope.

바닥 가진 시 PH15-7Mo 브라켓 진동 피로 파괴에 따른 모달 파라미터 추정

강다솜(Da Som Kang),김선민(Seonmin Kim),배승훈(Seung-Hoon Bae),조대원(Dae-Won Cho),김대환(Dae-Hwan Kim),박태국(Tae-Kook Park),백승훈(Seunghun Baek),양민혁(Minhyeok Yang),도승환(Seunghwan Do) 한국소음진동공학회 2023 한국소음진동공학회 논문집 Vol.33 No.6

In this study, a method for estimating modal parameters (natural frequency, damping ratio, mode shape) in vibration fatigue testing of brackets with base excitation is proposed. The circle fitting method was used to estimate the damping ratio from the acceleration transmissibility without considering external forces. The transmissibility equation was approximated and converted to a circular equation, and the center of the circle was found to be determined by the modal parameters. The experimental results showed that the damping and natural frequency changed rapidly following significant changes in the center of the circle representing the system; the change in the mode can be estimated. The proposed method allowed for estimation of the modal parameters without force measurement during the vibration test.

시스템식별을 통한 TLCD 풍진동 제어성능 검증

김홍진,최선영 한국풍공학회 2014 한국풍공학회지 Vol.18 No.2

풍진동에 의한 사용성의 문제를 해결하고 진동을 저감시키기 위하여 TLCD가 설치된 건물의 태풍에 의한 풍진동 계측결과를 바탕으로 시스템식별을 통하여 동특성 및 모달풍하중을 추정하고 TLCD의 풍진동 저감성능을 분석하였다. 대상건물은 인천 송도에 위치한 지상 64층 237m의 주거용건물로 상층부에 TLCD가 설치되었으며, 건물과 TLCD의 거동을 계측하기 위하여 풍향풍속계, 가속도계, 수위계및 인터넷기반 송수신시스템을 구축하였다. 계측된 건물의 가속도와 TLCD 액체의 변위결과를 바탕으로 구조물-TLCD 연계 모드를 식별하였으며 이를 바탕으로 구조물과 TLCD의 고유진동수를 식별하였다. 또한 계측된 구조물과 TLCD의 가속도응답으로부터 칼만필터를 이용하여 모달풍하중을역추정하여 식별된 구조물의 동특성을 바탕으로 TLCD의 풍진동 저감성능을 분석하였다. 분석결과 TLCD의 설치로 인하여 태풍에 의한 풍진동이 최대 29.9% 정도 저감되는 것으로 나타났다. As the height of buildings increases, it often requires supplementary damping system for occupants comfortin windy condition. This paper presents the performance of a tuned liquid column damper (TLCD) based on the systemidentification and the inverse wind load estimation. The TLCD was installed on 64-story, 237m residential buildingslocated in Incheon, Korea with a monitoring system consisting of an anemometer, accelerometers, water gauge, andinternet-based data logging system. In order to analyze the behavior of the building during the typhoon, the dynamicproperties of building and TLCD are identified from the measured responses. The modal wind load is then inverselyestimated from the TLCD and building accelerations using a Kalman filter, and the vibration reduction performanceof the TLCD is evaluated.

현수교 짧은 행어로프의 장력추정시 지점부 회전강성의 영향

이정휘(Jungwhee Lee),노상곤(Sang-Kon Ro),이영대(Young-Dai Lee),강병찬(Byung-Chan Kang) 한국소음진동공학회 2013 한국소음진동공학회 논문집 Vol.23 No.10

Tension force of hanger ropes has been recognized and utilized as an important parameter for health monitoring of suspension bridges. Conventional vibration method based on string theory has been utilized to estimate tension forces of relatively long hanger ropes without any problem, however it is convinced that the vibration method is not applicable for shorter hanger ropes in which the influence of flexural stiffness is not ignorable. Therefore, as an alternative of vibration method, a number of feasibility studies of system identification(SI) technique considering flexural stiffness of the hanger ropes are recently performed. In this study, the influence of support condition of the finite element model utilized for the SI method is investigated with numerical examples. The numerical examples are prepared with the specification of the Kwang-Ahn bridge hanger ropes, and it is revealed that the estimation result of the tension force can be varied from -21.6 % to +35.3 % of the exact value according to the consideration of the support condition of FE model. Therefore, it is concluded that the rotational stiffness of the support spring should be included to the list of the identification parameters of the FE model to improve the result of tension estimation.

Experimental evaluation of discrete sliding mode controller for piezo actuated structure with multisensor data fusion

Arunshankar, J.,Umapathy, M.,Bandhopadhyay, B. Techno-Press 2013 Smart Structures and Systems, An International Jou Vol.11 No.6

This paper evaluates the closed loop performance of the reaching law based discrete sliding mode controller with multisensor data fusion (MSDF) in real time, by controlling the first two vibrating modes of a piezo actuated structure. The vibration is measured using two homogeneous piezo sensors. The states estimated from sensors output are fused. Four fusion algorithms are considered, whose output is used to control the structural vibration. The controller is designed using a model identified through linear Recursive Least Square (RLS) method, based on ARX model. Improved vibration suppression is achieved with fused data as compared to single sensor. The experimental evaluation of the closed loop performance of sliding mode controller with data fusion applied to piezo actuated structure is the contribution in this work.

TMD가 설치된 구조물의 태풍거동 분석

김홍진,최선영,조성우,황재승,유은종,Kim, Hong-Jin,Choi, Sun-Young,Jo, Seong-Woo,Hwang, Jae-Seung,Yu, Eun-Jong 대한건축학회 2011 대한건축학회논문집 Vol.27 No.12

The wind response and performance of a tuned mass damper (TMD) are presented based on the system identification and the inverse wind load estimation. The TMD was installed on a 39-story, 184.6m steel building located in Incheon, Korea with a monitoring system consisting of an anemometer, accelerometers, and internet-based data logging system. On Sep. 2, 2010, the building experienced the Kompasu Typhoon, in which the peak wind speed, measured by an anemometer installed on the roof floor, was 49.7 m/s. In order to analyze the behavior of the building during the typhoon, the dynamic properties of building and TMD are identified from the measured responses. The modal wind load is then inversely estimated from the TMD and building accelerations using a Kalman filter, and the vibration reduction performance of the TMD is evaluated.

Experimental evaluation of discrete sliding mode controller for piezo actuated structure with multisensor data fusion

J. Arunshankar,M. Umapathy,B. Bandhopadhyay 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.11 No.6

This paper evaluates the closed loop performance of the reaching law based discrete sliding mode controller with multisensor data fusion (MSDF) in real time, by controlling the first two vibrating modes of a piezo actuated structure. The vibration is measured using two homogeneous piezo sensors. The states estimated from sensors output are fused. Four fusion algorithms are considered, whose output is used to control the structural vibration. The controller is designed using a model identified through linear Recursive Least Square (RLS) method, based on ARX model. Improved vibration suppression is achieved with fused data as compared to single sensor. The experimental evaluation of the closed loop performance of sliding mode controller with data fusion applied to piezo actuated structure is the contribution in this work.

TMD가 설치된 구조물의 태풍거동 분석

김홍진(Kim, Hong-Jin),최선영(Choi, Sun-Young),조성우(Jo, Seong-Woo),황재승(Hwang, Jae-Seung),유은종(Yu, Eun-Jong) 대한건축학회 2011 大韓建築學會論文集 : 構造系 Vol.27 No.12

The wind response and performance of a tuned mass damper (TMD) are presented based on the system identification and the inverse wind load estimation. The TMD was installed on a 39-story, 184.6m steel building located in Incheon, Korea with a monitoring system consisting of an anemometer, accelerometers, and internet-based data logging system. On Sep. 2, 2010, the building experienced the Kompasu Typhoon, in which the peak wind speed, measured by an anemometer installed on the roof floor, was 49.7 ㎧. In order to analyze the behavior of the building during the typhoon, the dynamic properties of building and TMD are identified from the measured responses. The modal wind load is then inversely estimated from the TMD and building accelerations using a Kalman filter, and the vibration reduction performance of the TMD is evaluated.