Optimum Placement and Control of Active Constrained Layer Damping using Modal Strain Energy Approach

2002 ◽  
Vol 8 (6) ◽  
pp. 861-876 ◽  
Author(s):  
J. Ro ◽  
A. Baz
Keyword(s):  
Strain Energy ◽  
High Efficiency ◽  
Effective Means ◽  
Optimization Technique ◽  
Optimal Placement ◽  
Constrained Layer Damping ◽  
Modal Strain Energy ◽  
Damping Characteristics ◽  
Active Constrained Layer Damping ◽  
Active Constrained Layer

The Active Constrained Layer Damping (ACLD) treatment has been used successfully for controlling the vibration of various flexible structures. It provides an effective means for augmenting the simplicity and reliability of passive damping with the low weight and high efficiency of active controls to attain high damping characteristics over broad frequency bands. In this paper, optimal placement strategies of ACLD patches are devised using the modal strain energy (MSE) method. These strategies aim at minimizing the total weight of the damping treatments while satisfying constraints imposed on the modal damping ratios. A finite element model is developed to determine the modal strain energies of plates treated with ACLD. The treatment is then applied to the elements that have highest MSE in order to target specific modes of vibrations. Numerical examples are presented to demonstrate the utility of the devised optimization technique as an effective tool for selecting the optimal locations of the ACLD treatment to achieve desired damping characteristics over a broad frequency band.

Vibration Control of Plates Using Self-Sensing Active Constrained Layer Damping Networks

2002 ◽  
Vol 8 (6) ◽  
pp. 833-845 ◽  
Author(s):  
J. Ro ◽  
A. Baz
Keyword(s):  
High Efficiency ◽  
Effective Means ◽  
Flexible Structures ◽  
Stable Operation ◽  
Constrained Layer Damping ◽  
Damping Characteristics ◽  
Low Weight ◽  
Active Constrained Layer Damping ◽  
Proportional Controller ◽  
Active Constrained Layer

The Active Constrained Layer Damping (ACLD) treatment has been used successfully for controlling the vibration of various flexible structures. The treatment provides an effective means of augmenting the simplicity and reliability of passive damping with the low weight and high efficiency of active controls to attain high damping characteristics over broad frequency bands. In this study, a self-sensing configuration of the ACLD treatment is utilized to suppress the bending and torsional vibrations of cantilevered plates simultaneously. The treatment considered ensures collocation of the sensors/actuators pairs in order to guarantee stable operation. The theoretical characteristics of the multi-layer treatment are presented in this paper and compared with the experimental performance. Attenuation of the amplitude of vibration of the first bending and torsional modes of more than 96% and 35% are obtained using proportional controller with voltages less than 93 volts. The corresponding attenuation becomes and 90% and 84% when a derivative controller is used with voltage of 82 volt.

Damping Characteristics of Beams with Enhanced Self-Sensing Active Constrained Layer Treatments Under Various Boundary Conditions

2004 ◽  
Vol 127 (2) ◽  
pp. 173-187 ◽  
Author(s):  
J. X. Gao ◽  
W. H. Liao
Keyword(s):  
Boundary Conditions ◽  
Careful Analysis ◽  
Constrained Layer Damping ◽  
Various Boundary Conditions ◽  
Damping Characteristics ◽  
Control Gain ◽  
Active Constrained Layer Damping ◽  
Damping Treatments ◽  
Active Constrained Layer ◽  
Loss Factors

In this paper, an energy-based approach is developed to investigate damping characteristics of beams with enhanced self-sensing active constrained layer (ESACL) damping treatments. Analytical formulations for the active, passive, and total hybrid modal loss factors of the cantilever and simply-supported beams partially covered with the ESACL are derived. The analytical formulations are validated with the results in the literature and experimental data for the cantilever beam. Beams with other boundary conditions can also be solved and discussed using the presented approach. The results show that the edge elements in the ESACL can significantly improve the system damping performance as compared to the active constrained layer damping treatment. The effects of key parameters, such as control gain, edge element stiffness, location, and coverage of the ESACL patch on the system loss factors, have been investigated. It has also been shown that the boundary conditions play an important role on the damping characteristics of the beam structure with the ESACL treatment. With careful analysis on the location and coverage of the partially covered ESACL treatment, effective vibration control for beams under various boundary conditions for specific modes of interest would be achieved.

scholarly journals Performance Characteristics of Active Constrained Layer Damping

1995 ◽  
Vol 2 (1) ◽  
pp. 33-42 ◽  
Author(s):  
A. Baz ◽  
J. Ro
Keyword(s):  
Broad Band ◽  
Structural Response ◽  
Piezoelectric Sensor ◽  
Performance Characteristics ◽  
Constrained Layer Damping ◽  
New Class ◽  
Damping Characteristics ◽  
Active Constrained Layer Damping ◽  
Passive Constrained Layer Damping ◽  
Active Constrained Layer

Theoretical and experimental performance characteristics of the new class of actively controlled constrained layer damping (ACLD) are presented. The ACLD consists of a viscoelastic damping layer sandwiched between two layers of piezoelectric sensor and actuator. The composite ACLD when bonded to a vibrating structure acts as a “smart” treatment whose shear deformation can be controlled and tuned to the structural response in order to enhance the energy dissipation mechanism and improve the vibration damping characteristics. Particular emphasis is placed on studying the performance of ACLD treatments that are provided with sensing layers of different spatial distributions. The effect of the modal weighting characteristics of these sensing layers on the broad band attenuation of the vibration of beams fully treated with the ACLD is presented theoretically and experimentally. The effect of varying the gains of a proportional and derivative controller and the operating temperature on the ACLD performance is determined for uniform and linearly varying sensors. Comparisons with the performance of conventional passive constrained layer damping are presented also. The results obtained emphasize the importance of modally shaping the sensor and demonstrate the excellent capabilities of the ACLD.

Dynamic modelling and analysis of smart carbon nanotube-based hybrid composite beams: Analytical and finite element study

2021 ◽  
pp. 146442072110197
Author(s):  
Madhur Gupta ◽  
Manas C Ray ◽  
Nagesh D Patil ◽  
Shailesh Ishwarlal Kundalwal
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Fibre ◽  
Constrained Layer Damping ◽  
Damping Characteristics ◽  
Reinforced Composite ◽  
Active Constrained Layer Damping ◽  
Smart Beam ◽  
Base Composite ◽  
Active Constrained Layer ◽  
Hybrid Carbon

In this work, the carbon nanotube-based hybrid carbon fibre-reinforced composite smart beam constraining the layer of an active constrained layer damping treatment is investigated using an in-house finite element model based on first-order shear deformation theory. The effect of in-plane and transverse-plane actuation of the integrated active constrained layer damping treatment layer on the damping characteristics of the novel smart cantilever hybrid carbon fibre-reinforced composite beam is considered. The parameters affecting the damping characteristics of the hybrid carbon fibre-reinforced composite substrate beam such as the volume fraction of both carbon nanotubes and carbon fibre, and the aspect ratio are also studied. Besides, the micromechanical model based on the mechanics of materials approach is developed to estimate the effective elastic coefficient of novel hybrid carbon fibre-reinforced composite lamina. The effective properties of hybrid carbon fibre-reinforced composite are predicted quantitatively by considering non-bonded interaction formed between carbon nanotubes and the polymer matrix. It is revealed that due to the incorporation of carbon nanotubes into the epoxy matrix, the effective longitudinal, transverse and shear properties of the hybrid carbon fibre-reinforced composite lamina are significantly enhanced. Our outcomes explore that the damping performance of the laminated hybrid carbon fibre-reinforced composite smart beam considering the incorporation of carbon nanotubes shows substantial improvement as compared to the base composite. To bring more clarity, the quantitative relative performance of hybrid carbon fibre-reinforced composite and base composite is presented. Our fundamental analysis sheds the light on the opportunities of developing efficient, high-performance and lightweight carbon nanotubes-based micro-electro-mechanical systems smart structures such as sensors, actuators and distributors.

Boundary Control of Beams Using Active Constrained Layer Damping

1997 ◽  
Vol 119 (2) ◽  
pp. 166-172 ◽  
Author(s):  
A. Baz
Keyword(s):  
Boundary Control ◽  
Distributed Parameter ◽  
Constrained Layer Damping ◽  
Damping Characteristics ◽  
Distributed Parameter Model ◽  
Active Constrained Layer Damping ◽  
Cantilevered Beams ◽  
Passive Constrained Layer Damping ◽  
Active Constrained Layer ◽  
Globally Stable

A variational mathematical model is developed using Hamilton’s principle to describe the dynamics of beams fully-treated with Active Constrained Layer Damping (ACLD) treatments. The resulting distributed-parameter model is utilized in devising a globally stable boundary control strategy which is compatible with the operating nature of the ACLD treatments. The effectiveness of the ACLD in damping out the vibration of cantilevered beams is determined for different control gains and compared with the performance of conventional Passive Constrained Layer Damping (PCLD). The results obtained demonstrate the high damping characteristics of the boundary controller particularly over broad frequency bands.

Active Constrained Layer Damping of Seismic Excitations

1995 ◽  
Author(s):  
A. Baz ◽  
S. Poh
Keyword(s):  
Sliding Mode ◽  
Effective Means ◽  
Three Dimensional ◽  
Constrained Layer Damping ◽  
Seismic Excitations ◽  
Vibrating Structures ◽  
Wide Range ◽  
Active Constrained Layer Damping ◽  
Classical Control ◽  
Active Constrained Layer

Abstract This paper aims at demonstrating the feasibility of Active Constrained Layer Dampers (ACLD) as an effective means for damping out seismic-induced vibrations of structures. The ACLD concept is motivated by the destructive effects that seismic excitations have on most of the uncontrolled structures. The effectiveness of the ACLD in enhancing the damping characteristics of conventional visco-elastic dampers is demonstrated experimentally for structures subjected to base excitations. Classical identification methods are used to identify a mathematical model that describes the interaction between the vibrating structures, the ACLD system and the seismic excitation. The model is integrated with a robust Continuous Sliding Mode (CSM) controller to reject the effect of the seismic excitations acting on vibrating structures with uncertain dynamic parameters. In this manner, the ACLD and the CSM algorithm present a simple but yet powerful alternative to classical control methods for rejecting seismic excitations and accommodating wide range of parameter uncertainty. The emphasis, in this paper, is placed on multi-story two-dimensional scaled structures which are provided with diagonal braces of the ACLD. However, the techniques developed can be readily extended to three-dimensional and larger structures.

Vibration Control of a Flexible Arm with Active Constrained Layer Damping

1997 ◽  
Vol 16 (4) ◽  
pp. 271-287 ◽  
Author(s):  
S. R. Tawfeic ◽  
A. Baz ◽  
A. A. Ismail ◽  
O. A. Azim ◽  
S. S. Karar
Keyword(s):  
Elastic Layer ◽  
Polyvinylidene Fluoride ◽  
Lateral Displacement ◽  
Flexible Manipulator ◽  
Constrained Layer Damping ◽  
Modal Strain Energy ◽  
Order Polynomial ◽  
Active Constrained Layer Damping ◽  
Active Constrained Layer ◽  
Piezo Electric

The vibration of a single link flexible manipulator is attenuated using the Active Constrained layer damping (ACLD) treatment. The ACLD treatment consists of a viscoelastic layer sandwiched between two piezo-electric layers acting as constraining layers with sensing and actuation capabilities. The shear deformation of the visco-elastic layer is controlled to enhance the energy dissipation mechanism and attenuate the vibration of the flexible manipulator. A finite element model is used to describe the dynamics of the system. A third order polynomial is used to describe the lateral displacement of the manipulator and a second order polynomial is used to describe the longitudinal displacements of the different layers of the manipulator. An appropriate control law is used to control the system. The Coupled Modal Strain energy technique is used to compute the equivalent viscous damping ratios for the elastic layer using the loss factor data of the material. The theoretical predictions of the model are compared with the experimental performance of a manipulator fully treated with a Dyad 606 visco-elastic layer sandwiched between two layers of polyvinylidene fluoride (PVDF) piezo-electric films. The results obtained clearly demonstrate the attenuation capabilities of the Actively-Controlled Constrained Layer Damping.

Sign in / Sign up

Export Citation Format

Share Document