Dynamic Characteristics And Vibration Control Of Sandwich Beams Filled With Electrorheological Fluids Undergoing A Large Overall Motion

Electrorheological fluids (ER fluids) is a kind of smart material whose physical properties such as viscosity and shear modulus can undergo instantaneous and reversible changes when subjected to different electric field. These unusual properties enable ER fluids to be employed in numerous potential engineering applications, such as shock absorbers, clutch/brake systems, valves and intelligent structures. One of the most commonly researching area of ER fluids structures is the ER fluids treated sandwich beam, in which the ER fluids completely fills the gap between two containing surface layers. These sandwich structures have adaptive control capabilities of varying the damping and stiffness of the beam by changing the intensity of applied electric field. Since Gandhi et al first proposed the application of ER fluids to adaptive structures, many achievements have been obtained in dynamic analysis and vibration control of sandwich beams or plates filled with ER fluids. However, research on the application of ER fluids to vibration control of motion beams is considerably rare.The focus of this research is to demonstrate the feasibility of using ER fluids for suppression vibrations of motion beams, especially the robot arm for IC packaging. A general dynamics model is developed for a sandwich beam filled with ER fluids undergoing large overall motions. In order to evaluate the vibration control effect of motion beams with an ER material layer, the numerical simulations and experimental tests are made to investigate the dynamic characteristics and vibration control of a rotating ER sandwich beam subjected to different structural components'properties and control parameters. Some interesting phenomena and results are achieved, which may be instructive for developing a new control approach to damp out the vibration of robot arm with high speed and high acceleration motion.The specific research works in this paper are as follows:1. The dynamic modeling theory for the multilayer composite beams undergoing a large overall motion is presented. Based on a higher order shear deformation beam theory along with the von-Karman strain field, a nonlinear dynamic model of the multilayer composite beams is developed by using Hamilton's principle. The nonlinear terms of elastic deformation caused by large overall rigid body motions, the coupling between the different material layers, and the large deflection are considered. The present model can not only be used to solve the dynamics of motion beam filled with ER fluids, but also be...