The analytical model of rheological fluid for vibration and noise control

Abstract

Rheological fluids (RF) also known as a controllable viscosity fluids (CVF) introduced in the area of vibration control of mechanical systems made possible a more efficient control of both: transient and continuous vibration. They are also used in design of sound barriers to control noise transmission loss and diaphragms for modification of noise absorption characteristics of sound absorbing materials. Their apparent viscosity is controllable by the use of external (electrical in electro-rheological ER or electromagnetic in magneto-rheological MR fluids) field. In the absence of applied external field, the RF exhibits Newtonian-like behavior. Applied external field changes this behavior and the RF shows in addition a yield shear stress which depends on strength of this field. In proposed model, the shear stress is expressed as a superposition of two components. One of them is proportional to the viscosity and relative velocity of a base fluid, and the second one, which depends on strength of applied external field. Modification of external field strength according to selected design parameter (velocity or time or distance—combination of them) allows to develop family of vibration or sound attenuating devices, which were not achievable before.