Constrained-layer damping

About: Constrained-layer damping is a research topic. Over the lifetime, 795 publications have been published within this topic receiving 15758 citations.

Vibration suppression of a CLD treated plate subject to a harmonic traveling load

Abstract: The vibrations of an annular plate with constrained layer damping (CLD) treatment subject to a traveling load are investigated. The equation of motion, after employing the assumed‐mode method, Donnell‐Mushtari‐Vlasov assumption and the Hamilton principle yielded terms of three plates’ displacements. The response is eventually, for each n, in terms of a single degree of freedom (SDOF) linear oscillator with hysteretic damping. The solution to a harmonic traveling load is then solved and discussed. Numerical results showed that the CLD treatment imposed significant damping onto the plate, especially as the plate reached its resonance. The interaction of harmonic driving frequency and traveling speed was also looked into. The results showed that to have the best damping effect, a relatively thin Visco Elastic Material (VEM) layer was enough and the damping was the most significant for n=0 and n=1 modes.

Constrained-layer Damping Applied to DCJ Vibration Isolation Design

Abstract: A dual piezoelectric cooling jet (DCJ) is an innovative cooling device that uses piezoelectric materials to generate high-speed vibrations, thereby causing changes in the flow field to achieve heat exchange. Despite its high cooling efficiency, a DCJ transfers vibrations through its supporting base to its peripheral devices. To attenuate vibrations from DCJs, this study employed constrained-layer damping (CLD)-a technique for suppressing vibrations-to develop a base for cooling devices and to propose a C-DCJ model. ANSYS simulation of the vibrations of a DCJ and the C-DCJ suggested that, under the same vibration conditions and with the same levels of cooling efficiency, the amplitude and acceleration of the base on the C-DCJ were 30%–50% lower than that on the DCJ. Thus, the proposed C-DCJ effectively isolated vibration transfer.

Experimental investigations of the effect of constraining layer parameters in vibration control of structures

Abstract: Today, the vibration control of structures is considered as one of the most important and useful study fields, which requires developing the new ways of control and simulating its effect on flexible structures. This study presents a passive vibration control technique applied to a beam type structures. The smart beam consists of an steel beam modeled in cantilevered configuration with surface bonded viscoelastic material and constrained layer. In this study, the effect of constrained layer material in vibration control is studied. In constrained layer damping, the constrained layer material modulus greatly influences the loss factor of the system. Here an attempt has been made to find the loss factor variation due to the constrained layer material modulus with different coverage. Patches of different lengths are bonded on the beam and its effect is analyzed. This study first investigates the effects of constrained layer materials analytically using Commercial software ANSYS 11.0. Then experiments are conducted to verify the ANSYS results. This research proves that there is a considerable increase in the loss factor due to the stiffer constraining layer material as compared with the base layer.

Identification and simulation of a beam with active constrained layer damping using MATAB/SIMULINK

Abstract: Linear transfer function models based on frequency response identification techniques are developed to describe the flexural vibration of a cantilever beam when excited using piezoceramic patches bonded to a constrained layer damping treatment. Predictions of dynamic behavior, obtained using the models, are validated by comparison with results from laboratory experiments. The models are then used in open loop and closed loop velocity feedback control simulations to demonstrate the improvements in stability and performance.

Model-based control of plate vibrations using active constrained layer damping

Abstract: In this thesis, the author presents a numerical and experimental study of the application of active constrained layer damping to a clamped-clamped plate. Piezoelectric actuators with modal controllers are used to improve the performance of vibration suppression from the passive constrained layer damping treatment. Surface damping treatments are often effective at suppressing higher frequency vibrations in thin-walled structures such as beams, plates and shells. However, the effective suppression of lower frequency modes usually requires the additional of an active vibration control scheme to augment the passive treatment. Advances in the technologies associated with so-called smart materials are dramatically reducing the cost, weight and complexity of active structural control and make it feasible to consider active schemes in an increasing number of applications. Specifically, a passive constrained layer damping treatment is enhanced with an active scheme employing a piezoceramic (PZT) patch as the actuator. Starting with an established finite element formulation it is shown how model updating and model reduction are required to produce a low-order state-space model which can be used as the basis for active control. The effectiveness of the formulation is then demonstrated in a numerical study. Finally, in the description of the experimental study it is shown how modes in the frequency range from 0 to 600 Hz are effectively suppressed: the two lowest modes (bending and torsional) through active control, the higher modes (around ten in number) by the passive constrained damping layer. The study'S original contribution lies in the experimental demonstration that given a sufficiently accurate model of the plate and passive constrained damping layer, together with a suitable active feedback control algorithm, spillover effects are not significant even when using a single sensor and single actuator. The experimental traces show, in some instances, minor effects due to spillover. However, it can be concluded that the presence of the passive layer introduces sufficient damping into the residual modes to avoid any major problems when using only the minimum amount of active control hardware.