• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.613-617
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• 2004

This paper presents an experimental study on vibration characteristics of an automotive roof with viscoelastic material. The goal of the study is to extract modal parameters (natural frequency, loss factor, and mode shape) of automotive roof with unconstrained and constrained layer damping treatment. To determine the effective position of the viscoelastic patch on a roof, vibration tests have been carried out for two cases; Aluminum plate with viscoelastic patch on maximum strain energy, and aluminum plate with viscoelastic patch on nodal line. From the result of aluminum plate, it is found that the viscoelastic patch should be attached on the Place with maximum strain energy Part. For the automotive root five Patches of unconstrained or constrained viscoelastic material have been attached on the position of maximum strain energy. This paper addresses that the proper position of viscoelastic patch is very important and the concept of maximum strain energy may be a good criterion f3r the placement of viscoelastic patch.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.1032-1038
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• 2002

The Active Constrained Layer Damping(ACLO) combines the simplicity and reliability of passive damping with the low weight and high efficiency of active control to attain high damping characteristics. The proposed ACLD treatment consists of a viscoelastic damping which is sandwiched between an active piezoelectric layer and a host structure. In this manner, the smart ACLD consists of a Passive Constrained Layer Damping(PCLD) which is augmented with an active control in response to the structural vibrations. The Arc type shell model is introduced to describe the interactions between the vibrating host structure, piezoelectric actuator and visco damping, The system is modeled by applying ARMAX model and changing a state-space form through the system identification method. An optimum control law for piezo actuator is obtain by LQR(Linear Quadratic Regulator) Method. The performance of ACLD system is determined and compared with PCLD in order to demonstrate the effectiveness of the ACLD treatment, Also, the actuation capability of a piezo actuator is examined experimentally by using various thickness of Viscoelastic Materials(VEM).

• 한국소음진동공학회논문집
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• 제12권12호
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• pp.964-969
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• 2002

The flexural vibration of laminated composite beams with passive constrained layer damping has been investigated to design structure with maximum possible damping capacity. The equations of motion are derived for flexural vibrations of symmetrical, multi-layer laminated beams. The damping ratio and modal damping of the first bending mode are calculated by means of Iterative complex eigensolution method. This paper addresses a design strategy of laminated composite under flexural vibrations.

• 한국자동차공학회논문집
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• 제13권6호
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• pp.31-37
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• 2005

This paper presents an experimental study on vibration characteristics of an automotive roof with damping material. The goal of the study is to extract modal parameters(natural frequency, loss factor, and mode shape) of automotive roof with damping materials treatment. To determine the effective positions and thickness of the damping material on a roof, vibration tests have been carried out for six cases; an aluminum plate with damping material on maximum strain energy positions, and an aluminum plate with damping material on nodal lines. From the result of aluminum plate, it is found that the damping material should be placed on the location with maximum strain energy part. For the automotive roof, patches of constrained damping material, which has two different density, have been attached to the positions of the maximum strain energy with four kinds of thicknesses. This paper shows that the proper positioning of the damping material is very important and the effective thickness is about twice that of the roof panel.