Damping and Vibration Control

Advanced structures, such as high speed or long distance civil aeroplanes, automobiles, satellite antennae and the NASA space station, are designed with minimum weight to improve performance and reduce operating costs. These lightweight designs are necessarily more flexible than traditional structures and can suffer from vibration causing increased noise levels, a shorter fatigue life or dynamic performance degradation. Some form of passive or active suppression is required to reduce the vibration levels.

One option is active vibration control systems based on piezoceramic actuators. Research has concentrated on the control methods for these structures and the design of modal sensors and actuators to avoid the spillover problem, where high frequency dynamics can destablise the control system.

Usually smart structures will have passive, as well as active, damping. Thus modelling structures incorporating viscoelastic damping materials which introduce hysterisis is very important. The difficulty is in obtaining suitable time domain models, from material properties specified in the frequency domain. Time domain models are vital to design suitable controllers to minimise vibration, and to simulate the response of the closed loop system. One standard method for modelling viscoelastic materials is to introduce extra degrees of freedom into the structure. The dynamics of these extra degrees of freedom is such that the viscoelastic properties in the frequency domain are reproduced. Unfortunately many extra degrees of freedom are often required, making the approach computationally expensive and thus motivating research into model reduction methods for damped structures. Ideally the element matrices should be reduced before they are assembled into the full model, but the standard reduction methods do not work very well in this application. The modelling of structures with viscoelastic components has also inspired work into the dynamics of structures with significant damping.

Selected References

Active Vibration Control

MI Friswell, On the Design of Modal Actuators and Sensors. Journal of Sound and Vibration, 241(3), March 2001, 361-372.

MI Friswell, Partial and Segmented Modal Sensors for Beam Structures. Journal of Vibration and Control, 5(4), July 1999, 619-637.

K Jian & MI Friswell, Distributed Modal Sensors for Rectangular Plate Structures. Journal of Intelligent Material Systems and Structures, 18(9), September 2007, 939-948.

K Jian & MI Friswell, Designing Distributed Modal Sensors for Plate Structures using Finite Element Analysis. Mechanical Systems and Signal Processing, 20(8), November 2006, 2290-2304.

MI Friswell & DJ Inman, On the Relationship Between Positive Position Feedback and Output Feedback Controllers. Journal of Smart Materials and Structures, 8(3), June 1999, 285-291.

MI Friswell, DJ Inman & RW Rietz, Active Damping of Thermally Induced Vibration. Journal of Intelligent Material Systems and Structures, 8(8), August 1997, 678-685.

JA Etches, JJ Scholey, GJ Williams, IP Bond, PH Mellor, MI Friswell & NAJ Lieven, Exploiting Functional Fibers in Advanced Composite Materials. Journal of Intelligent Material Systems and Structures, 18(5), May 2007, 449-458.

M Abdelghani & MI Friswell, Sensor Validation for Structural Systems with Multiplicative Sensor Faults. Mechanical Systems and Signal Processing, 21(1), January 2007, 270-279.

MI Friswell & DJ Inman, Sensor Validation for Smart Structures. Journal of Intelligent Material Systems and Structures, 10(12), December 1999, 973-982.

Passive Damping Materials

MI Friswell, S Adhikari & Y Lei, Non-local Finite Element Analysis of Damped Beams. International Journal of Solids and Structures, 44(22-23), November 2007, 7564-7576.

S Adhikari, MI Friswell & Y Lei, Modal Analysis of Non-viscously Damped Beams. Journal of Applied Mechanics, 74(5), September 2007, 1026-1030.

MI Friswell, S Adhikari & Y Lei, Vibration Analysis of Beams with Non-local Foundations using the Finite Element Method. International Journal for Numerical Methods in Engineering, 71(11), September 2007, 1365-1386.

Y Lei, MI Friswell & S Adhikari, A Galerkin Method for Distributed Systems with Non-local Damping. International Journal of Solids and Structures, 43(11-12), June 2006, 3381-3400.

MI Friswell & AW Lees, The Modes of Non-Homogeneous Damped Beams. Journal of Sound and Vibration, 242(2), April 2001, 355-361.

MI Friswell & DJ Inman, Reduced Order Models of Structures with Viscoelastic Components. AIAA Journal, 37(10), October 1999, 1318-1325.

MI Friswell, DJ Inman & MJ Lam, On the Realisation of GHM Models in Viscoelasticity. Journal of Intelligent Material Systems and Structures, 8(11), November 1997, 986-993.

Last updated February 2009 by M I Friswell