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In this paper the authors address the problem of suppressing the vibrations of a clamped-clamped plate using an active constrained layer damping treatment. This treatment involves adding viscoelastic and metallic constraining layers to the host plate and then augmenting this arrangement with an active feedback scheme using piezoelectric actuators. The basis of the control strategy is an effective model of the plate together with the passive damping treatment. The paper summarizes the modelling procedures including the finite-element formulation, model reduction and model updating. By this means a low-order model, capable of accounting for the observed behaviour, is developed.Emphasis is placed upon the design and implementation of active modal controllers based upon the reduced and updated model. Four actuator/sensor configurations are examined in both numerical and experimental studies. It is shown that effective control of the first two modes of vibration (bending and torsion) can be achieved using only a single actuator and single sensor. However, the most effective configuration involves two actuators and two sensors operating as two independent control channels. It is shown that through suitable design, the active constrained layer damping treatment is capable of avoiding problems due to spillover effects.

In this research study, the high-frequency squeal noise of a brake disc was found to occurred at a frequency of about 15 kHz. The potential root cause has been studied where mode frequency coupling and shape locking mechanism of brake disc and brake pads components are the main investigated topic. From the vehicle field test and the Dynamometer test, the braking condition, friction coefficient and braking pressure, have been confirmed to be used in numerical experiments. The updated finite element model (FEM) with the modal testing data of the existing brake components are formulated for the Complex Eigenvalue Analysis (CEA). In this study, the modification is based on in-board and out-board cheek thickness of the brake disc. Two of nine modifications of the brake disc cheek thickness are proposed with the method of separation the brake disc out-of-plane and in-plane modes and the method of avoiding shape locking between the brake disc and the brake pads modes. The constructed prototypes are verified with the vehicle field test and well agreed with the CEA.

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