Vibration Control of Plates Using Electromagnetic Compressional Damping Treatment

Abstract

A new class of structural damping treatments is introduced. This class is the Electromagnetic Compressional Damping Treatment (ECDT) which relies in its operation on a viscoelastic damping layer sandwiched between an electromagnet and a permanent magnet. Interaction between the magnets generates magnetic forces that enhance the compressional damping mechanism of the viscoelastic layer. With proper tuning of the magnetic forces, in response to the structural vibration, undesirable resonances and catastrophic failures can be avoided. The fundamentals and the underlying phenomena associated with the ECDT are investigated theoretically and experimentally.

A finite element model is developed to describe the interaction between the dynamics of flexible plates, the visco-elastic damping layer and the electro-magnetic actuators. The validity of the developed finite element model is checked experimentally using aluminum plates treated with single and multi-ECDT patches. The plate/ECDT system is subjected to sinusoidal excitations and its multi-mode response is monitored when the electro-magnetic actuator is activated or not. Several control strategies are considered to activate the electro-magnetic actuator including simple PD controllers. The performance of the uncontrolled and controlled system is determined at various operating conditions. Comparisons with conventional Passive Constrained Layer Damping (PCLD) treatments emphasize the potential of the ECDT treatment as an effective means for controlling structural vibrations.

Get full access to this article

View all access options for this article.

References

Baz, A , “Active Constrained Layer Damping,” U.S. Patent 5,485,053, 1996.

Baz, A. , “Magnetic Constrained Layer Damping,” Proc. Of the 11th Conf. On Structural Dynamics and Control, VPI & SU, Blacksburg, VA, pp. 333-344, May 1997.

Baz, A. and J. Ro , “Vibration Control of Plates with Active Constrained Layer Damping,” J. of Smart Materials and Structures, Vol. 5, pp. 272-280, 1996.

Baz, A. and T. Chen , “Boundary Control of Axi-Symmetric Vibrations of Cylindrical Shells Using Active Constrained Layer Damping,” AIAA paper #97-0360, AIAA 35th Aerospace Sciences Meeting, Reno, NV, Jan. 1997.

Bathe, K. J. , Finite Element Procedures, Prentice Hall, Englewood Cliffs, NJ, 1996.

Cheng, D. , Field and Wave Electromagnetics, Second Ed., Addison-Wesley, Reading, MA, 1992.

Douglas, B. , “Compressional Damping in Three-Layer Beams Incorporating nearly Incompressible Visco-elastic cores,” J. of Sound & Vibration, Vol. 104, No. 2, pp. 343-347, 1986.

Douglas, B. and J. Yang , “Transverse Compressional Damping in the Vibratory Response of Elastic-Viscoelastic-Elastic Beams,” AIAA Journal, Vol. 20, No. 9, pp. 1284-1290, 1978.

Gentilman, R. , D. F. Fiore , H. T. Pham , K. W. French and L. J. Bowen , “Fabrication and Properties of 1-3 PZT Polymer Composites,” Ceramic Transactions, Vol. 43, pp. 239-247, 1994.

10.

Ghandi, K. and N. W. Hagood , “Nonlinear Finite Element Modeling of Phase Transitions in Electro-Mechanically Coupled Materials,” Proc. of Smart Stuctures and Materials Conf., ed. by V. Varadan and J. Chandra , Vol. SPIE-2715, pp. 121-140, 1996.

11.

Ghoneim, H. , “Bending and Twisting Vibration Control of a Cantilever Plate via Electromechanical Surface Damping,” Proc. of Smart Structures and Materials Conf., ed. by C. Johnson , Vol. SPIE-2445, pp. 28-39, 1995.

12.

Golla, D. F. and P. Hughes , “Dynamics of Viscoelastic Structures—A Time Domain, Finite Element Formulation,” J. of Applied Mechanics, Vol. 52, pp. 897-906, 1985.

13.

Hagood, N. and A. von Flottow , “Damping of Structural Vibrations with Piezoelectric Materials and Passive Electrical Networks,” J. of Sound and Vibration, Vol. 146, pp. 243-268, 1991.

14.

Haung, S. C. , D. Inman and E. Austin , “Some Design Considerations for Active and Passive Constrained Layer Damping Treatments,” J. of Smart Materials and Structures, Vol. 5, pp. 301-314, 1996.

15.

Sylwan, O.

“Shear And Compressional Damping Effects of Constrained Layered Beam,”

J. of Sound and Vibration, Vol. 118, No. 1, pp. 35-45, 1987.