• Title, Summary, Keyword: Smart Structure

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Design Method Development of Smart TMD for Retractable-Roof Spatial Structure (개폐식 대공간 구조물을 위한 스마트 TMD 설계기법 개발)

  • Kim, Hyun-Su;Kang, Joo-Won
    • Journal of Korean Association for Spatial Structures
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    • v.17 no.3
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    • pp.107-115
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    • 2017
  • In this paper, a structural design method of a smart tuned mass damper (TMD) for a retractable-roof spatial structure under earthquake excitation was proposed. For this purpose, a retractable-roof spatial structure was simplified to a single degree of freedom (SDOF) model. Dynamic characteristics of a retractable-roof spatial structure is changed based on opened or closed roof condition. This condition was considered in the numerical simulation. A magnetorheological (MR) damper was used to compose a smart TMD and a displacement based ground-hook control algorithm was used to control the smart TMD. The control effectiveness of a smart TMD under harmonic and earthquake excitation were evaluated in comparison with a conventional passive TMD. The vibration control robustness of a smart TMD and a passive TMD were compared along with the variation of natural period of a simplified structure. Dynamic responses of a smart TMD and passive TMD under resonant harmonic excitation and earthquake load were compared by varying mass ratio of TMD to total mass of the simplified structure. The design procedure proposed in this study is expected to be used for preliminary design of a smart TMD for a retractable-roof spatial structure.

A Study on the Damping Characteristics of a Hybrid Smart Structure Using Electrorheological Fluids and PZT (전기유동유체와 압전세라믹을 이용한 복합지능구조물의 감쇠특성 연구)

  • 윤신일;박근효;한상보;최윤대
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.382-387
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    • 2003
  • Many type of smart materials and control laws are available to actively adjust the structure from various external disturbances. Usually, a certain type of control law to activate a specific smart material is tell established, but the effectiveness of the control scheme is limited by the choice of the smart materials and the responses of the structure. ER fluid is adequate to provide small but arbitrary control forces at any point along the structure. It was found that active vibration control of the structure embedded with ER fluids fluidly to suppress the vibration excited with broad band frequency due to the limited change of the structure characteristics. To compensate this limited effect of the control scheme with ER fluid alone, PPF control using PZT as an actuator is added to construct a hybrid controller.

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Dynamic Modeling and Vibration Control of Smart Hull Structure (스마트 Hull 구조물의 동적 모델링 및 능동 진동 제어)

  • Sohn, Jung-Woo;Kim, Heung-Soo;Choi, Seung-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.650-655
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    • 2006
  • Dynamic modeling and active vibration control of smart hull structure using Macro Fiber Composite (MFC) actuator is conducted. Finite element modeling is used to obtain equations of motion and boundary effects of smart hull structure. Modal analysis is carried out to investigate the dynamic characteristics of the smart hull structure, and compared to the results of experimental investigation. Negative velocity feedback control algorithm is employed to investigate active damping of hull structure. It is observed that non-resonant vibration of hull structure is suppressed effectively by the MFC actuators.

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Dynamic Modeling and Vibration Control of Smart Hull Structure (스마트 Hull 구조물의 동적 모델링 및 능동 진동 제어)

  • Sohn, Jung-Woo;Kim, Heung-Soo;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.8
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    • pp.840-847
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    • 2006
  • Dynamic modelingand active vibration control of smart hull structure using Macro Fiber Composite (MFC) actuators are conducted. Finite element modeling is used to obtain equations of motion and boundary effects of smart hull structure. Modal analysis is carried out to investigate the dynamic characteristics of the smart hull structure, and compared to the results of experimental investigation. Negative velocity feedback control algorithm is employed to investigate active damping of hull structure. It is observed that non-resonant vibration of hull structure is suppressed effectively by the MFC actuators.

Vibration Control of Smart TMD for Retractable-Roof Spatial Structure considering Closed and Open Roof Condition

  • Kim, Hyun-Su;Kang, Joo-Won
    • International journal of steel structures
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    • v.17 no.4
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    • pp.1539-1550
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    • 2017
  • A retractable-roof system is frequently adapted to the spatial structure of stadiums and sports halls. The geometric shape and mass location are varied by opening or closing the roof, resulting in a change in the dynamic characteristics of the retractable-roof spatial structure. A passive tuned mass damper (TMD) shows good vibration control performance of the spatial structures when it is tuned properly. Because the closed or open roof condition of a retractable spatial structure causes off-tuning, multiple smart tuned mass dampers (STMD) were developed in this study to increase the control performance in the case of off-tuning. Initially, the dynamic characteristics variations of the opened or closed roof conditions were investigated using an example retractable spatial structure. The control performances of a passive TMD and smart TMD were evaluated under off-tuning conditions. For this purpose, artificial ground motion was generated based on the Korean Building Code (KBC) 2016. Multiple smart TMDs were comprised of magnetorheological (MR) dampers. A fuzzy logic control algorithm (FLC) was used to generate the command voltages sent to the MR dampers and the FLC was optimized by a multi-objective genetic algorithm. Numerical analyses showed that the smart TMD had better control performance than the passive TMD. In the case of the off-tuning condition, the difference in control performance between passive and smart TMDs increased.

Parameter Study for Optimal Design of Smart TMD (스마트 TMD의 최적설계를 위한 파라메터 연구)

  • Kim, Hyun-Su;Kang, Joo-Won
    • Journal of Korean Association for Spatial Structures
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    • v.17 no.4
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    • pp.123-132
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    • 2017
  • A smart tuned mass damper (TMD) was developed to provide better control performance than a passive TMD for reduction of earthquake induced-responses. Because a passive TMD was developed decades ago, optimal design methods for structural parameters of a TMD, such as damping constant and stiffness, have been developed already. However, studies of optimal design method for structural parameters of a smart TMD were little performed to date. Therefore, parameter studies of structural properties of a smart TMD were conducted in this paper to develop optimal design method of a smart TMD under seismic excitation. A retractable-roof spatial structure was used as an example structure. Because dynamic characteristics of a retractable-roof spatial structure is changed based on opened or closed roof condition, control performance of smart TMD under off-tuning was investigated. Because mass ratio of TMD and smart TMD mainly affect control performance, variation of control performance due to mass ratio was investigated. Parameter studies of structural properties of a smart TMD was performed to find optimal damping constant and stiffness and it was compared with the results of optimal passive TMD design method. The design process developed in this study is expected to be used for preliminary design of a smart TMD for a retractable-roof spatial structure.

Active Vibration Control of Smart Hull Structure in Underwater Using Micro-Fiber Composite Actuators (MFC 작동기를 이용한 수중 Hull 구조물의 능동 진동 제어)

  • Kwon, Oh-Cheol;Sohn, Jung-Woo;Choi, Seung-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.466-471
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    • 2008
  • Structural vibration and noise are hot issues in underwater vehicles such as submarines for their survivability. Therefore, active vibration and noise control of submarine, which can be modeled as hull structure, have been conducted by the use of piezoelectric materials. Traditional piezoelectric materials are too brittle and not suitable to curved geometry such as hull structures. Therefore, advanced anisotropic piezoceramic actuator named as Macro-Fiber Composite (MFC), which can provide great flexibility, large induced strain and directional actuating force is adopted for this research. In this study, dynamic model of the smart hull structure is established and active vibration control performance of the smart hull structure is evaluated using optimally placed MFC. Actuating performance of MFC is evaluated by finite element analysis and dynamic modeling of the smart hull structure is derived by finite element method considering underwater condition. In order to suppress the vibration of hull structure, Linear-Quadratic-Gaussian (LQG) algorithm is adopted. After then active vibration control performance of the proposed smart hull structure is evaluated with computer simulation and experimental investigation in underwater. Structural vibration of the hull structure is decreased effectively by applying proper control voltages to the MFC actuators.

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Active Vibration Control of Smart Hull Structure Using MFC Actuators (MFC 작동기를 이용한 스마트 Hull 구조물의 능동 진동 제어)

  • Sohn, Jung-Woo;Kim, Heung-Soo;Choi, Seung-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.217-222
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    • 2005
  • Active vibration control of smart hull structure using Macro Fiber Composite (MFC) actuator is performed. Finite element modeling is used to obtain governing equations of motion and boundary effects of end-capped smart hull structure. Equivalent interdigitated electrode model is developed to obtain piezoelectric couplings of MFC actuator. Modal analysis is conducted to investigate the dynamic characteristics of the hull structure, and compared to the results of experimental investigation. MFC actuators are attached where the maximum control performance can be obtained. Active controller based on Linear Quadratic Gaussian (LQG) theory is designed to suppress vibration of smart hull structure. It is observed that closed loop damping can be improved with suitable weighting factors in the developed LQG controller and structural vibration is controlled effectively.

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Active Vibration Control of Smart Hull Structure Using MFC Actuators (MFC 작동기를 이용한 스마트 Hull 구조물의 능동 진동 제어)

  • Sohn, Jung-Woo;Kim, Heung-Soo;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.12
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    • pp.1408-1415
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    • 2005
  • Active vibration control of smart hull structure using Macro Fiber Composite (MFC) actuator is performed. Finite element modeling is used to obtain governing equations of motion and boundary effects of end-capped smart hull structure. Equivalent interdigitated electrode model is developed to obtain piezoelectric couplings of MFC actuator. Modal analysis is conducted to investigate the dynamic characteristics of the hull structure, and compared to the results of experimental investigation. MFC actuators are attached where the maximum control performance can be obtained. Active controller based on Linear Quadratic Gaussian (LQG) theory is designed to suppress vibration of smart hull structure. It is observed that closed loop damping can be improved with suitable weighting factors in the developed LQG controller and structural vibration is controlled effectively.

Investigations on state estimation of smart structure systems

  • Arunshankar, J.
    • Smart Structures and Systems
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    • v.25 no.1
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    • pp.37-45
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    • 2020
  • This paper aims at enlightening the properties, computational and implementation issues related to Kalman filter based state estimation algorithms and sliding mode observers, by applying them for estimating the states of a smart structure system. The Kalman based estimators considered in this work are Kalman filter and information filter and, the sliding mode observers considered are Utkin observer and higher order sliding mode observer. A fourth order linear time invariant model of a piezo actuated beam is used in this work. This structure is embedded with four number of piezo patches, of which two act as sensors, one as disturbance actuator and the other as control actuator. The performance of the state estimation algorithms is evaluated through simulation, for the first two vibrating modes of the piezo actuated structure, when the structure is maintained at first mode and second mode resonance.