Minimizing vibration response of cylindrical shells through layout optimization of passive constrained layer damping treatments

2005 ◽  
Vol 279 (3-5) ◽  
pp. 739-756 ◽  
Author(s):  
H. Zheng ◽  
C. Cai ◽  
G.S.H. Pau ◽  
G.R. Liu
Keyword(s):  
Cylindrical Shells ◽  
Layout Optimization ◽  
Vibration Response ◽  
Constrained Layer Damping ◽  
Damping Treatments ◽  
Passive Constrained Layer Damping

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.

Experimental Studies on Active Vibration Control of a Beam Using Hybrid Active∕Passive Constrained Layer Damping Treatments

2005 ◽  
Vol 127 (5) ◽  
pp. 515-518 ◽  
Author(s):  
Pankaj K. Langote ◽  
P. Seshu
Keyword(s):  
Piezoelectric Materials ◽  
Active Vibration Control ◽  
Experimental Studies ◽  
Time Domain Analysis ◽  
Constrained Layer Damping ◽  
Active Vibration ◽  
The Time Domain ◽  
Damping Treatments ◽  
Passive Constrained Layer Damping ◽  
Hybrid Damping

Hybrid damping designs with active piezoelectric materials and passive viscoelastic materials (VEMs) combine the advantages of both active and passive constrained layer damping treatments. In this study, experiments have been conducted on nine systems viz., bare beam, active damping (AD), passive constrained layer damping (PCLD—three variants) and hybrid active∕passive constrained layer damping (Hybrid AD∕PCLD—four variants). Based on the time domain analysis of these systems, it is shown that the “best” performance is obtained using a hybrid damping configuration wherein the VEM and the piezoelectric layers are acting separately.

Experimental and Finite Element Analysis of Stand-Off Layer Damping Treatments for Beams

2007 ◽  
Author(s):  
Jessica M. H. Yellin ◽  
I. Y. Shen ◽  
Per G. Reinhall
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Frequency Response ◽  
Viscoelastic Layer ◽  
Constrained Layer Damping ◽  
Response Functions ◽  
Element Analysis ◽  
Frequency Response Functions ◽  
Damping Treatments ◽  
Passive Constrained Layer Damping

Passive stand-off layer (PSOL) and slotted stand-off layer (SSOL) damping treatments are presently being implemented in many commercial and defense designs. In a PSOL damping treatment, a stand-off or spacer layer is added to a conventional passive constrained layer damping treatment. In an SSOL damping treatment, slots are included in the stand-off layer. A set of experiments using PSOL and SSOL beams in which the geometric properties of the stand-off layer were varied was conducted to analyze the contribution of the stand-off layer to the overall system damping. This set of experiments measured the frequency response functions for a series of beams in which the total slotted area of the stand-off layer was held constant while the number of slots in the stand-off layer was increased for a constant stand-off layer material. Finite element analysis models were developed in ANSYS to compare the predicted frequency response functions with the experimentally measured frequency response functions for the beams treated with PSOL and SSOL damping treatments. In these beams, the bonding layers used to fabricate these treatments were found to have a measurable and significant effect on the frequency response of the structure. The finite element model presented here thus included an epoxy layer between the base beam and the stand-off layer, a contact cement layer between the stand-off layer and the viscoelastic layer, and a method for modeling delamination.

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.

Some Pitfalls of Simplified Modeling for Viscoelastic Sandwich Beams

2000 ◽  
Vol 122 (4) ◽  
pp. 434-439 ◽  
Author(s):  
Eric M. Austin ◽  
Daniel J. Inman
Keyword(s):  
Strain Energy ◽  
Large Range ◽  
Sandwich Beams ◽  
Constrained Layer Damping ◽  
Modal Strain Energy ◽  
Skew Distributions ◽  
Transverse Vibrations ◽  
Simplified Modeling ◽  
Damping Treatments

It is commonplace in academia to base models of constrained-layer damping treatments on the assumption that the facesheets displace identically during transverse vibrations. This assumption is valid for a large range of problems, particularly for problems common in the era when damping was achieved by applying foil-backed treatments to thin panels. The authors show using a very simple example that oversimplified modeling can skew distributions of modal strain energy, a common indicator of damping. [S0739-3717(00)00204-X]

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