• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.1
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• pp.9-15
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• 2010

In this paper, dynamic modeling of hull structure including surface-bonded piezoelectric composite actuator was developed and structural vibration control performance was evaluated. Cylindrical shell structure with end-caps was considered as a host structure which could be used as a simple model of fuselage of aircraft and underwater vehicles. An advanced piezoelectric composite, macro-fiber composite(MFC), which has been developed in NASA Langley Research Center was applied for the effective structural vibration control. MFC has great flexibility by using piezoceramic fiber sheet and enhanced piezoelectric effect for in-plane motion by utilizing interdigitated electrode. Governing Equations were derived from the finite element model and modal characteristics were investigated. Modal test was conducted to verify the finite element model. Optimal controller was designed and implemented for the evaluation of vibration control performance. Structural vibration was controlled effectively by applying proper control input to the piezoelectric actuators.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.7 s.124
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• pp.587-595
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• 2007

Performance evaluation of advanced piezoelectric composite actuator is conducted with its application of structural vibration control. Characteristics of MFC(macro fiber composite) actuator are investigated by comparing traditional piezoceramic patch actuator. Finite element modeling is used to obtain equations of motion and boundary effects of smart hull structure with MFC actuator. Dynamic characteristics of the smart hull structure are studied through modal analysis and experimental investigation. LQG control algorithm is employed to investigate active damping of hull structure. It is observed that vibration of hull structure is suppressed effectively by the MFC actuators.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1119-1124
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• 2007

Performance evaluation of advanced piezoelectric composite actuator is conducted with its application of structural vibration control. Characteristics of MFC (macro fiber composite) actuator are investigated by comparing traditional piezoceramic patch actuator. Finite element modeling is used to obtain equations of motion and boundary effects of smart hull structure with MFC actuator. Dynamic characteristics of the smart hull structure are studied through modal analysis and experimental investigation. LQG control algorithm is employed to investigate active damping of hull structure. It is observed that vibration of hull structure is suppressed effectively by the MFC actuators.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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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.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.2
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• pp.138-145
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• 2009

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 piezocomposite 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.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.1
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• pp.47-51
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• 2015

In this paper, feasibility of dynamic characteristics recovery of delaminated composite structure is numerically studied by using active control algorithm and piezoelectric actuator. Macro-fiber composite(MFC), which has great flexibility and high actuating force, is considered as an actuator in this work. After construction of finite element model for delaminated composite structure based on improved layerwise theory, modal characteristics are investigated and changes of natural frequencies and mode shapes, caused by delamination, are observed. Then, active control algorithm is realized and implemented to system model and control performances are numerically evaluated. Dynamic characteristics of delaminated composite structure are effectively recovered to those of healthy composite structure.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.10
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• pp.148-153
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• 2001

Active control of flexural vibrations of smart laminated composite beams has been carried out using piezoceramic sensor/actuator and viscoelastic material. The beams with passive constrained layer damping hale been analyzed by formulating the equations of motion through the use of extended Hamilton's principle. The dynamic characteristics such as damping ratio and modal damping of the beam are calculated for various fiber orientations by means of iterative complex eigensolution method. This paper addresses a design strategy of laminated composite under flexural vibrations to design structure with maximum possible damping capacity.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1332-1336
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• 2005

It could make the LIghtweight Piezoelectric Composite Actuator (LIPCA) damageable by the cyclic large deformation. If the progressive microvoid coalescence of LIPCA interlaminar took place, the decrease of the stiffness and the weakness of stress transmission and fiber bridging effect would make the fatigue characteristics worse suddenly. Therefore, it is required to study the variation of fatigue behavior and interlaminar condition in LIPCA under resonant frequencies. These studies such as the changeable fatigue phase and interlaminar behavior of LIPCA affected by the resonant frequencies should be carried out due to the strong anisotropy of CFRP layer. Hence, these studies are as follows. 1) The residual stresses distribution of interlaminar in LIPCA using the Classical Lamination Theory (CLT). 2) Comparative analysis of interlaminar behavior for the intact LIPCA versus LIPCA containing an artificial delamination during resonant frequency.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.641-644
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• 2005

The aim of this research is to evaluate the relationship between the total effective moment $(M^E)$ and Bemoulli-Euler bending moment (M) when the ply orientations of UD CFRP in Piezoelectric Zirconate Titanate Composite Actuator (PZTCA) are changed. The obtained results as follows. Firstly, as the performance test results by the CFRP ply orientation, the performance of [0] and [90] were stable. However, while the performance of [+45] was suddenly decreased after 5 hours. Secondly, the change of $M^E$ by the CFRP ply orientation was evaluated. As the CFRP ply orientation was increased from [0] to [+60], the $M^E$ were gradually decreased. However, they became a little bit increased from [+60] to [90]. Finally, after the change of M by the CFRP ply orientation was evaluated, it was found that $M^E=2.2M$ was valid for just [0] and that there was a relationship between $M^E$ and M according to the ply orientation.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.286-289
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• 2004

This paper presents the fatigue characteristics of LIPCA (LIghtweight Piezo-Composite Actuator) device system. The LIPCA device system is composed of a piezoelectric ceramic layer and fiber reinforced lightweight composite layers. Typically a PZT ceramic layer is sandwiched by a top fiber layer with low CTE (coefficient of thermal expansion) and base layers with high CTE. The advantages of the LIPCA design are weight reduction by using the lightweight fiber reinforced plastic layers without compromising the generation of high force and large displacement and design flexibility by selecting the fiber direction and the size of prepreg layers. To predict the degradation of actuation performance of LIPCA due to fatigue, the cyclic electric loading tests using PZT specimens were performed and the strain for a given excitation voltage was measured during the test. The results from the PZT fatigue test were implemented into CLPT (Classical Laminated Plate Theory) model to predict the degradation of LIPCA's actuation displacement. The fatigue characteristic of PZT was measured using a test system composed of a supporting jig, a high voltage power supplier, data acquisition board, PC, and evaluated.