Hybrid damping through intelligent constrained layer treatments
01 Jul 1994-Journal of Vibration and Acoustics (American Society of Mechanical Engineers)-Vol. 116, Iss: 3, pp 341-349
TL;DR: In this article, a hybrid damping design that integrates active and passive dampings through intelligent constrained layer (ICL) treatments is proposed, which consists of a viscoelastic shear layer sandwiched between a piezoelectric constraining cover sheet and the structure to be damped.
Abstract: This paper is to propose a viable hybrid damping design that integrates active and passive dampings through intelligent constrained layer (ICL) treatments. This design consists of a viscoelastic shear layer sandwiched between a piezoelectric constraining cover sheet and the structure to be damped. According to measured vibration response of the structure, a feedback controller regulates axial deformation of the piezoelectric layer to perform active vibration control. In the meantime, the viscoelastic shear layer provides additional passive damping. The active damping component of this design will produce adjustable and significant damping. The passive damping component of this design will increase gain and phase margins, eliminate spillover, reduce power consumption, improve robustness and reliability of the system, and reduce vibration response at high frequency ranges where active damping is difficult to implement. To model the dynamics of ICL, an eighth-order matrix differential equation governing bending and axial vibrations of an elastic beam with the ICL treatment is derived. The observability, controllability, and stability of ICL are discussed qualitatively for several beam structures. ICL may render the system uncontrollable or unobservable or both depending on the boundary conditions of the system. Finally, two examples are illustrated in this paper. The first example illustrates how an ICL damping treatment, which consists of an idealized, distributed sensor and a proportional-plus-derivative feedback controller, can reduce bending vibration of a semi-infinite elastic beam subjected to harmonic excitations. The second example is to apply an ICL damping treatment to a cantilever beam subjected to combined axial and bending vibrations. Numerical results show that ICL will produce significant damping.
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TL;DR: In this paper, a finite element model is developed to analyze the dynamics and control of flat plates which are partially treated with multi-patches of active constrained layer damping (ACLD) treatments.
Abstract: Bending vibration of flat plates is controlled using patches of active constrained layer damping (ACLD) treatments. Each ACLD patch consists of a visco-elastic damping layer which is sandwiched between two piezo-electric layers. The first layer is directly bonded to the plate to sense its vibration and the second layer acts as an actuator to actively control the shear deformation of the visco-elastic damping layer according to the plate response. With such active/passive control capabilities the energy dissipation mechanism of the visco-elastic layer is enhanced and the damping characteristics of the plate vibration is improved. A finite element model is developed to analyze the dynamics and control of flat plates which are partially treated with multi-patches of ACLD treatments. The model is validated experimentally using an aluminum plate which is 0.05 cm thick, 25.0 cm long and 12.5 cm wide. The plate is treated with two ACLD patches, each of which is made of SOUNDCOAT (Dyad 606) visco-elastic layer sandwiched between two layers of AMP/polyvinylidene fluoride (PVDF) piezo-electric films. The piezo-electric axes of the patches are set at zero degrees relative to the plate longitudinal axis to control the bending mode. The effect of the gain of a proportional control action on the system performance is presented. Comparison between the theoretical predictions and the experimental results suggest the validity of the developed finite element model. Also, comparisons with the performance of conventional passive constrained layer damping clearly demonstrate the merits of the ACLD as an effective means for suppressing the vibration of flat plates.
146 citations
TL;DR: In this paper, the design parameters and control gains of the resulting Active Constrained Layer Damping (ACLD) treatments are optimally selected, in order to maximize the modal damping ratios and minimize the total weight of the damping treatment.
Abstract: Conventional Passive Constrained Layer Damping (PCLD) treatments with viscoelastic cores are provided with built-in sensing and actuation capabilities to actively control and enhance their vibration damping characteristics. The design parameters and control gains of the resulting Active Constrained Layer Damping (ACLD) treatments are optimally selected, in this paper, for fully-treated beams using rational design procedures. The optimal thickness and shear modulus of the passive visco-elastic core are determined first to maximize the modal damping ratios and minimize the total weight of the damping treatment. The control gains of the ACLD are then selected using optimal control theory to minimize a weighted sum of the vibrational and control energies. The theoretical performance of beams treated with the optimally selected ACLD treatment is determined at different excitation frequencies and operating temperatures. Comparisons are made with the performance of beams treated with optimal PCLD treatments and untreated beams which are controlled only by conventional Active Controllers (AC). The results obtained emphasize the potential of the optimally designed ACLD as an effective means for providing broad-band attenuation capabilities over wide range or operating temperatures as compared to PCLD treatments.
141 citations
TL;DR: In this article, a finite element for planar beams with active constrained layer (ACL) damping treatments is presented, where a time-domain viscoelastic material model and the ability to readily accommodate segmented (i.e., non-continuous) constraining layers are discussed.
Abstract: A finite element for planar beams with active constrained layer (ACL) 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.
136 citations
TL;DR: In this article, a review of the open literature concerning geometric configurations, modeling approaches and control algorithms for hybrid active (piezoelectric)-passive (viscoelastic) damping treatments of beams is provided.
Abstract: Hybrid active-passive damping treatments combine the reliability, low cost and robustness of viscoelastic damping treatments and the high performance, modal selective and adaptive piezoelectric active control. Numerous hybrid damping treatments have been reported in the literature. They differ mainly by the relative positions of viscoelastic treatments, sensors and piezoelectric actuators. Therefore, the present article provides a review of the open literature concerning geometric configurations, modeling approaches and control algorithms for hybrid active (piezoelectric)-passive (viscoelastic) damping treatments of beams. In addition, using a unified finite element model able to represent sandwich damped beams with piezoelectric laminated faces and an optimal control algorithm, the geometric optimization of four hybrid treatments is studied through treatment length and viscoelastic material thickness parametric analyses. A comparison of the performances of these hybrid damping treatments is carried out a...
122 citations
Cites background or methods from "Hybrid damping through intelligent ..."
...Although these are frequency-dependent, a constant version of this formula was often retained (Azvine, Tomlinson, and Wynne, 1995; Baz, 1997a; 1997b; 1997c; Shen, 1994; 1997) for simplicity....
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...Using the standard ACL configuration of Plump and Hubbard Jr. (1986), Shen (1994; 1996) and Liao and Wang (1997a) used optical sensors to measure the beam tip deflection (Figure 1(a)), which was processed and transmitted to the piezoelectric actuator to provide damping enhancement....
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...Shen (1994) considered a PD algorithm of a cantilever beam tip deflection....
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...Proportional and/or Derivative Baz and Ro (1995a; 1995b), Huang, Inman, and Austin (1996), Lesieutre and Lee (1996), Shen (1994), Trindade, Benjeddou, and Ohayon (2001b), Varadan, Lim, and Varadan (1996), Veley and Rao (1996), Yellin and Shen (1996) Direct Velocity Feedback Azvine, Tomlinson, and…...
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...…1995a), Huang, Inman, and Austin (1996), Kapadia and Kawiecki (1997), Lesieutre and Lee (1996), Liao and Wang (1997a), Plump and Hubbard Jr. (1986), Shen (1994; 1996), Trindade, Benjeddou, and Ohayon (2000a; 2000b), Varadan, Lim, and Varadan (1996), Yellin and Shen (1996) APCL Figure 1(g),(h)…...
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TL;DR: In this paper, an analysis of active damping of geometrically nonlinear vibrations of functionally graded magneto-electro-elastic (FGMEE) plates integrated with the patches of the active constrained layer damping (ACLD) treatment is presented.
95 citations