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.

Analytical Formulation and Damping Analysis of Beams With Enhanced Active Constrained Layer Treatments Under Various Boundary Conditions

2005 ◽  
Author(s):  
J. X. Gao ◽  
W. H. Liao
Keyword(s):  
Boundary Conditions ◽  
Analytical Formulation ◽  
Edge Elements ◽  
Various Boundary Conditions ◽  
Damping Characteristics ◽  
Damping Treatments ◽  
Active Constrained Layer ◽  
Loss Factors

In this paper, an energy-based approach is developed to investigate damping characteristics of beams partially covered with enhanced self-sensing active constrained layer (ESACL) damping treatments. Analytical formulations for the active, passive, and total hybrid modal loss factors of partially covered beams with ESACL under various boundary conditions are derived. The results show that the edge elements in the ESACL can significantly improve the system damping performance as compared to the active constrained layer treatment. The effects of other key parameters and the boundary conditions have also been investigated.

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.

Characteristics of Enhanced Active Constrained Layer Damping Treatments With Edge Elements: Part II — System Analysis

1997 ◽  
Author(s):  
W. H. Liao ◽  
K. W. Wang
Keyword(s):  
System Analysis ◽  
Careful Analysis ◽  
Constrained Layer Damping ◽  
Passive Damping ◽  
Active System ◽  
Control Effort ◽  
Edge Elements ◽  
Active Constrained Layer Damping ◽  
Critical Edge ◽  
Active Constrained Layer

Abstract This paper presents some important characteristics of enhanced active constrained layer damping (EACL) treatments for vibration controls. Specific interests are on understanding how the edge elements will influence the active action authority, the passive damping ability, and their combined effects in EACL. Analysis results indicate that the edge elements can significantly improve the active action transmissibility of the current active constrained layer damping (ACL) treatment due to the bypass effect. Although the edge elements will slightly reduce the viscoelastic material (VEM) passive damping, the EACL will still have significant damping from the VEM. Combining the overall active and passive actions, the new EACL with sufficiently stiff edge elements not only could achieve better performance with less control effort compared to the current ACL system, but also could outperform the purely active system. With careful analysis, we can map out the required critical edge element stiffness for successful designs. In addition, analysis also shows that the EACL treatment is a more robust design. That is, it could outperform both the purely active and passive systems throughout a much broader design space than the current ACL configuration. With these desirable characteristics, the EACL could be used to realize an overall optimal active-passive hybrid system.

Sign in / Sign up

Export Citation Format

Share Document