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.

Optimal design for partial constrained layer damping

Abstract: Constrained layer damping is widely used in vibration suppression for plate like structures,especially the partial constrained layer damping(PCLD).Optimal design for PCLD has been studied in this paper by using Ansys.The finite element model of PCLD is established in Ansys firstly,then,in order to improve the designated modal damping ratios of a plate,topology optimization design is carried out based on the FE model with Cellular Automata(CA) algorithm and the modified version(CAM) by the author.Finally,integrated optimization method of multiparameter design and topology shape design of the PCLD is presented in this paper.Numerical simulations show that the method presented in this paper gains higher damping effectiveness.It can provide a simple design guideline for PLCD optimization in engineering applications with plates and shells.

A finite element for beams having segmented active constrained layers with frequency-dependent viscoelastic material properties

Abstract: A finite element for planar beams with active constrained layer damping treatments is presented. Features of this non-shear locking element include a time-domain viscoelastic material model, and the ability to readily accommodate segmented (i.e. non-continuous) constraining layers. These features are potentially important in active control applications: the frequency-dependent stiffness and damping of the viscoelastic material directly affects system modal frequencies and damping; the high local damping of the viscoelastic layer can result in complex vibration modes and differences in the relative phase of vibration between points; and segmentation, an effective means of increasing passive damping in long-wavelength vibration modes, affords multiple control inputs and improved performance in an active constrained layer application. The anelastic displacement fields (ADF) method is used to implement the viscoelastic material model, enabling the straightforward development of time-domain finite elements. The performance of the finite element is verified through several sample modal analyses, including proportional-derivative control based on discrete strain sensing. Because of phasing associated with mode shapes, control using a single continuous ACL can be destabilizing. A segmented ACL is more robust than the continuous treatment, in that the damping of modes at least up to the number of independent patches is increased by control action.

Vibration suppression performance of piezoceramic and magnetostrictive materials in constrained layer damping

Abstract: Active constrained layer damping has been shown to be an effective way of controlling structural vibration. The success of the technique depends significantly on the strain imparted to the constraining layer by an actuator made of a smart material -- typically a piezoelectric ceramic. The possibility of using magnetostrictive smart patches as actuators is explored in this regard. Comparisons of performance are made between commonly used piezoelectric ceramic and proposed magnetostrictive actuators on the basis of maximum power consumption. It is shown that magnetostrictives offer benefits particularly in the lower frequencies.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Influence from Fraction of Coverage to the Damping Capacity of Partial Constrained Layer Damping Structure

Abstract: In this paper, the influence from fraction of coverage to the damping capacity of partial constrained layer damping structure was studied by single point hammer test with two sides simply supported constraints and finite element simulation based on the theory of modal strain energy. Combining with time domain and vibration acceleration with the composite loss factors from finite element analysis, vibration reduction effect was remarkable with the fraction of coverage from 40% to 80%. The combined result showed that partial constrained layer damping structure with 80% damping layer coverage had better damping capacity.

Effectiveness of section length optimization for constrained viscoelastic layer damping treatments

Abstract: It is well known that constrained viscoelastic layer damping treatments provide an effective means of passive control for structural vibration. These treatments dissipate vibrational energy by inducing shear strain in a thin layer of viscoelastic material. Our interest is in adding passive damping to a structure as an augmentation to active control. For such applications it is desirable to achieve high damping performance in a given frequency range with a minimum of added weight. Constrained layer damping treatments most commonly employ spatially continuous constraining layers over the entire viscoelastic layer. Plunkett and Lee have shown that the effectiveness of the damping treatment can be significantly increased by sectioning the constraining layer into segments of optimal length for the target frequency range. The authors have observed that few have recognized the degree of improvement achievable through this method. The purpose of this paper is to illustrate the effectiveness of the method, through examples. It is demonstrated that, for a particular laboratory structure, the damping of the modes of interest can easily be increased by a factor of 10 or more by properly sectioning the constraining layer. The structure considered is a simple aluminum flat bar which is the arm of a single link flexible robot experiment. The damping material is 3M ISD-11O, and the constraining layer is 10 mu steel shim. Data is presented to compare experimental results with theoretical and finite element predictions. Plunkett and Lee's theory is used for theoretical analysis. The finite element model was developed based on MSC/NASTRAN code.