Active, Shunted, and Passive Constrained Layer Damping for the Vibration Suppression of a Flexible Four-Bar Mechanism

2001 ◽  
Vol 7 (4) ◽  
pp. 551-563 ◽  
Author(s):  
H. Ghoneim ◽  
Mansour A. Karkoub
Keyword(s):  
Vibration Suppression ◽  
Constrained Layer Damping ◽  
Passive Constrained Layer Damping

Optimum Layout of Passive Constrained Layer Damping Treatment Using Genetic Algorithms

2010 ◽  
Author(s):  
S. W. Hou ◽  
Y. H. Jiao ◽  
Z. B. Chen
Keyword(s):  
Shear Modulus ◽  
Viscoelastic Material ◽  
Large Scale ◽  
Vibration Suppression ◽  
Flexible Structures ◽  
Wide Frequency Range ◽  
Viscoelastic Layer ◽  
Constrained Layer Damping ◽  
Passive Constrained Layer Damping ◽  
Loss Factors

The passive constrained layer damping (CLD) treatments have been used widely for vibration suppression of various flexible structures. Fully covered CLD treatment is extensively used to depress the vibration over a wide frequency range in engineering applications. In most of these treatments it is required that the CLD treatment should not significantly increase the weight or volume. This paper focuses on damping optimization of fully coating beam with a constrained viscoelastic layer. The governing equation of motion of a CLD covered beam is derived using an energy approach and Lagrange’s method. The assumed modes method is employed in solving the equation to obtain the modal loss factors which are used as the objective of optimal layout. A genetic algorithm with large-scale mutation method is employed to search for the optima of the thicknesses of both the constraining layer (CL) and the viscoelastic layer (VL) and the shear modulus of the viscoelastic material (VEM) with the restriction of added volume of the total CLD treatment. Numerical results show that the optima of three design variables, the thicknesses of the CL and the VL and the shear modulus of its viscoelastic material, are highly relevant to each other. The softer or thinner constraining layer requires a softer viscoelastic material for an optimal damping treatment, and high value of the elastic modulus of the base beam matches high shear modulus of the viscoelastic material. The variation of the CL thickness decreases slowly and that of the VL thickness increases with the increase of the thickness of the CLD treatment. Stiffer constraining layer assure greater modal loss factors.

Hybrid Control of Rotating Beams Using Pattern Search Based Optimization Technique

2018 ◽  
Author(s):  
Rajiv Kumar Vashisht ◽  
Qingjin Peng
Keyword(s):  
Smart Materials ◽  
Optimization Technique ◽  
Flexible Structures ◽  
Pattern Search ◽  
Feedback Controller ◽  
Structural Vibration ◽  
Flexible Beam ◽  
Constrained Layer Damping ◽  
Rotating Beams ◽  
Passive Constrained Layer Damping

Rotating beams are quite common in rotating machinery e.g. fans of compressors in an airplane. This paper presents the experimental, hybrid, structural vibration control of flexible structures to enhance the vibration behavior of rotating beams. Smart materials have been used as sensors as well as actuators. Passive constrained layer damping (PCLD) treatment is combined with stressed layer damping technique to enhance the damping characteristics of the flexible beam. To further enhance the damping parameters, a closed form robust feedback controller is applied to reduce the broadband structural vibrations of the rotating beam. The feed forward controller is designed by combing with the feedback controller using a pattern search based optimization technique. The hybrid controller enhances the performance of the closed loop system. Experiments have been conducted to validate the effectiveness of the presented technique.

Damping Characteristics of a Cantilever Plate Using Permanent Magnetic Constrained Layer Damping Strip Treatment

2012 ◽  
Vol 450-451 ◽  
pp. 466-471
Author(s):  
Ming Li ◽  
Hui Ming Zheng
Keyword(s):  
Ritz Method ◽  
Constrained Layer Damping ◽  
Structural Vibrations ◽  
Torsional Mode ◽  
Calculation Of Parameters ◽  
New Class ◽  
Damping Characteristics ◽  
Special Cases ◽  
Cantilever Rectangular Plate ◽  
Passive Constrained Layer Damping

Significant improvement of damping characteristics can be achieved by using the new class of magnetic constrained layer damping treatment (MCLD). This paper presents the damping properties of the first and second torsional mode for a five-layer cantilever rectangular plate treated with partial MCLD. The Rayleigh-Ritz method and Hamilton’s principle are employed in the analysis. We have chosen both single and segmented patches with different sizes. It can be observed that for the two modes single-patched MCLD treatment induces less improvement of damping characteristics especially for the short patch. The effects of calculation of parameters like placement strategies of discrete patches, the length of patches are analyzed and discussed. The results obtained from analytical show that the optimum location of the patch, for the torsional mode, is at edge of the plate. Favorable comparisons with the conventional passive constrained layer damping treatment (PCLD) on various special cases of the problem are obtained. The results demonstrate MCLD treatment still improvements over PCLD in damping structural vibrations.

scholarly journals Topology Optimization of Passive Constrained Layer Damping with Partial Coverage on Plate

2013 ◽  
Vol 20 (2) ◽  
pp. 199-211 ◽  
Author(s):  
Weiguang Zheng ◽  
Yingfeng Lei ◽  
Shande Li ◽  
Qibai Huang
Keyword(s):  
Finite Element ◽  
Topology Optimization ◽  
Objective Function ◽  
Optimization Procedure ◽  
Constrained Layer Damping ◽  
Flat Plates ◽  
Modal Strain Energy ◽  
Partial Coverage ◽  
Material Interpolation ◽  
Passive Constrained Layer Damping

The potential of using topology optimization as a tool to optimize the passive constrained layer damping (PCLD) layouts with partial coverage on flat plates is investigated. The objective function is defined as a combination of several modal loss factors solved by finite element-modal strain energy (FE-MSE) method. An interface finite element is introduced to modeling the viscoelastic core of PCLD patch to save the computational space and time in the optimization procedure. Solid isotropic material with penalization (SIMP) method is used as the material interpolation scheme and the parameters are well selected to avoid local pseudo modes. Then, the method of moving asymptote (MMA) is employed as an optimizer to search the optimal topologies of PCLD patch on plates. Applications of two flat plates with different shapes have been applied to demonstrate the validation of the proposed approach. The results show that the objective function is in a steady convergence process and the damping effect of the plates can be enhanced by the optimized PCLD layouts.

scholarly journals Performance Characteristics of the Magnetic Constrained Layer Damping

2000 ◽  
Vol 7 (2) ◽  
pp. 81-90 ◽  
Author(s):  
A. Baz ◽  
S. Poh
Keyword(s):  
Permanent Magnets ◽  
Effective Means ◽  
Performance Characteristics ◽  
Structural Vibration ◽  
Constrained Layer Damping ◽  
Structural Vibrations ◽  
New Class ◽  
Elastic Layers ◽  
Damping Treatments ◽  
Passive Constrained Layer Damping

A new class of surface damping treatment is proposed to provide effective means for attenuating undesirable structural vibrations. The proposed treatment relies in its operation on the use of smart damping treatments which consist of integrated arrays of constrained visco-elastic damping layers that are controlled passively by a specially arranged network of permanent magnets. The interaction between the magnets and the visco-elastic layers aims at enhancing the energy dissipation characteristics of the damping treatments. In this manner, it would be possible to manufacture structures that are light in weight which are also capable of meeting strict constraints on structural vibration when subjected to unavoidable disturbances.Emphasis is placed here on introducing the concept and the basic performance characteristics of this new class of smart Magnetic Constrained Layer Damping (MCLD) treatments. Comparisons are also presented with conventional Passive Constrained Layer Damping (PCLD) in order to determine the merits and limitation of the MCLD treatments.

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