دانلود رایگان مقاله انگلیسی ویژگی های پویای غیر خطی یک میراگر ویسکوز مایع با ارتعاش ریز - اشپرینگر 2018

Abstract

This study is concerned with the nonlinear dynamic characteristics of a micro-vibration fluid viscous damper used in a satellite. When a control moment gyroscope is working, it produces micro-vibrations, which is a disadvantage for imaging equipment. Taking a single-tube micro-vibration fluid viscous damper as our research subject, a nonlinear dynamic model of the micro-vibration fluid viscous damper under harmonic excitation is proposed. Then, the analytical form of the pressure gradient force is derived. Considering the entrance effect in the orifice, the nonlinear elastic force and nonlinear damping force are analyzed. The results reveal that if the entrance effect is not considered, the elastic force and damping force are linear forces. When the entrance effect is considered, the damper has a nonlinear elastic force and a nonlinear damping force. These nonlinear forces are related to the orifice length, diameter, fluid viscosity, excitation amplitude and frequency. In the low-frequency domain, the differences between the two cases are small, while in the high-frequency domain, they are considerable.

10 Conclusions

In this paper, a nonlinear dynamic model of a microvibration fluid viscous damper has been proposed. While considering the entrance effect in the damping orifice, the nonlinear damping force and the nonlinear elastic force are analyzed. The results reveal the following:

(1) The pressure gradient force contains a damping force, an elastic force, and a transient force. The elastic force provides stiffness, the damping force consumes vibration energy, and the transient force decays with time. The transient force decays with time according to an exponential law or oscillation law. It depends on the diameter and length of the damping orifice and the viscosity of the silicone oil.

(2) When ignoring the entrance effect in the orifice, the damping force and elastic force are linear forces. When considering the entrance effect in the damping orifice, the damping force and elastic force are nonlinear forces. At low frequencies, the pressure gradient forces in the two cases are nearly the same, but at high frequencies, they are quite different.

(3) The nonlinear damping force and the nonlinear elastic force have a relationship with the diameter and length of the damping orifice, viscosity, amplitude, and frequency. The nonlinear damping force and elastic force change with these parameters.