Vibration Reduction By Elastic Support Dry Friction Damper

It is well known, damper is an important component reducing vibrations in rotating machines running at high speed, for example in aero-engines. In different types of dampers such as squeeze oil film dampers, metal rubber dampers and rubber dampers have found successful applications.In this paper, a new type of damper-elastic support/dry friction is designed to suppress vibrations in rotating machines. It provides a rotor with damping by friction or two disks. One disk is fixed on the end cross section or elastic support and another one is placed in a fixed support. If the support moves, due to rotor vibration, then a relative motion between the support and the disk will occur. This will lead to a dry friction dissipating the vibration energy. The friction damper works in this principle.The dry friction force depends upon the force pressing the disk on the end cross section of the support and the friction coefficient associated with surface roughness and materials. Hence the damper can actively be controlled by changing the pressing force.The main works and conclusions are the following:The structural of elastic support/dry friction damper is introduced. A test rig is designed and set up to examine the feasibility and effectiveness of elastic support dry friction damper. The experiments include the steady state and the transient condition.The data of steady state and Bode diagram of transient condition show elastic support dry friction damper can reduce the vibration from rotating unbalance. The data of Bode diagram prove the dry friction damper can reduce the peak amplitude of vibration at critical speed.Coulomb dry friction model is used. The differential equations of rotor- elastic support-dry friction damper system are given. The results show that elastic support/dry friction damper can stabilize and reduce the vibration of rotor system. It is shown in theoretical analysis that elastic support dry friction damper can stabilize the free vibration of rotor. A boundary limit of the stabilization provided by the dry friction damper is obtained.In the hysteretic dry friction model, the hysteresis curve is simplified by Fourier method and harmonic balance method. The vibration responses are calculated to single degree of freedom model and two degree of freedom model of rotor- elastic support- dry friction damper system.