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...

Hybrid Active-Passive Damping Treatments Using Viscoelastic and Piezoelectric Materials: Review and Assessment

Surface-mounted piezoelectric materials poled in the same direction as the applied electric field are known to induce membrane strains only. This could be seen as their conventional extension actuation mechanism. However, when piezoelectric materials are constrained and poled perpendicularly to the applied electric field, they act through their shear modes. This is the newly defined shear actuation mechanism. The present paper compares both mechanisms with the help of an adaptive sandwich beam finite element, with either active surface layers (for the extension mechanism) or active core (for the shear mechanism). Segmented configurations are studied for cantilever beams. Deflection, stress and vibration characteristics are compared for various parameters (structure/actuator stiffness and thickness ratios, actuator position and length). The shear actuation mechanism is found to present several promising features for brittle piezoceramics' use. In particular, it was found that the shear actuation mechanism is more efficient than the extension mechanism for stiff structures and thick piezoelectric actuators.

https://iopscience.iop.org/article/10.1088/0964-1726/9/3/313/pdf

Piezoelectric actuation mechanisms for intelligent sandwich structures

A first attempt is made to survey and discuss the recent advances in hybrid active-passive struc tural vibrations control. The survey is illustrated with figures and tables for helpful use by resea...

Advances in Hybrid Active-Passive Vibration and Noise Control Via Piezoelectric and Viscoelastic Constrained Layer Treatments:

To add damping to systems, viscoelastic materials (VEM) are added to structures. In order to enhance the damping effects of the VEM, a constraining layer is attached, creating a passive constrained layer damping (PCLD) treatment. When this constraining layer is an active element, the treatment is called active constrained layer damping (ACLD). Recently, the investigation of ACLD treatments has shown it to be an effective method of vibration suppression. In this paper, the treatment of a beam with a separate active and PCLD element will be investigated. Two new hybrid variations will be introduced. A Ritz-Galerkin approach is used to obtain discretized equations of motion. The damping is modeled using the Golla-Hughes-McTavish (GHM) method and the system is analyzed in the time domain. By optimizing on the performance and control effort for both the active and passive case, it will be shown that hybrid treatment is capable of lower control effort with more inherent damping, and is therefore a better approa...

Vibration Control through Passive Constrained Layer Damping and Active Control

The twenty-first century could be called the 'Multifunctional Materials Age' The inspiration for multifunctional materials comes from nature, and therefore these are often referred to as bio-inspired materials Bio-inspired materials encompass smart materials and structures, multifunctional materials and nano-structured materials This is a dawn of revolutionary materials that may provide a 'quantum jump' in performance and multi-capability This book focuses on smart materials, structures and systems, which are also referred to as intelligent, adaptive, active, sensory and metamorphic The purpose of these materials from the perspective of smart systems is their ability to minimize life-cycle cost and/or expand the performance envelope The ultimate goal is to develop biologically inspired multifunctional materials with the capability to adapt their structural characteristics (such as stiffness, damping and viscosity) as required, monitor their health condition, perform self-diagnosis and self-repair, morph their shape and undergo significant controlled motion over a wide range of operating conditions

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Smart Structures Theory

Active constrained layer damping treatments promise to be an effective means of vibration suppression in structures. Basically, the concept consists in either replacing or augmenting the constraining layer of a constrained viscoelastic material with piezoceramic actuators in an attempt to improve vibration suppression properties by capitalizing on both passive and active damping techniques. An important issue in such configurations is the concept that the actuation ability of the piezoceramic is reduced by the viscoelastic layer, rather than enhanced. On the other hand, an active constraining layer increases the shear in the viscoelastic and thus forms an effective means of enhancing the damping mechanism. Some design considerations for pure passive, pure active control, and active constrained layer damping are discussed here. Several authors have reported comparisons and formulations of active constrained layer damping techniques. The approach presented here differs in that it employs an energy principle for the equations of a beam with partial active/passive constrained layer damping treatments. To simulate a realistic design problem, the optimal sizing, length, and thickness of treatments subject to a total thickness restriction is studied for cases of active constrained layer, passive constrained layer, and pure active control. The results show that the active constrained layer damping treatment provides better vibration suppression than passive damping treatments, and it even out-performs pure active control for low-gain applications.

https://iopscience.iop.org/article/10.1088/0964-1726/5/3/008/pdf

Some design considerations for active and passive constrained layer damping treatments

Active constrained layer damping consists of either replacing or augmenting the constraining layer for a viscoelastic material with piezoceramic actuators in an attempt to improve vibration suppression properties by synergism between passive and active damping techniques. An important question in such configurations is whether the reduction in actuation ability of the piezoceramic on the beam due to a relatively soft viscoelastic layer is compensated for by enhanced passive damping due to increased shear in the viscoelastic material. Some tradeoffs between pure passive, pure active control, and active constrained layer damping are discussed here. Velocity feedback and LQR are investigated. Several authors have researched and developed formulations for active constrained layer damping techniques. The approach presented here differs from most in that it employs an energy principle for the equations of a beam with partial active/passive constrained layer damping transients. An offshoot of this is the thickness of the viscoelastic layer can be arbitrarily small (even zero), thus opening up the possibility of simulating the realistic design problem where the optimal sizing, length, and thickness of a treatment is subject to a total thickness restriction. The results show that the active constrained layer damping treatment provides better vibration suppression than passive damping treatments, and it even out performs pure active control for low-gain applications.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

S. C. Huang

Papers

Some design considerations for active and passive constrained layer damping treatments

Design considerations for active constrained layer damping treatments