Dynamic study of a simplified mechanical system with presence of dry friction

In aero engines, amplitudes of blade vibrations are frequently reduced by c entrifugal flyweights, called friction peak limiters, which exert a dry fri ction force under the blade platforms. To understand the physical phenomena which cause reduction of vibration amplitudes, a system comprising two deg rees of freedom, but generally representative of a real system, is studied. It is shown that system response can be found by analyzing the sliding and the stuck state. It appears therefore that the most important phenomenon c ontrolling movement is the change of boundary conditions. In addition, the effect of other parameters is analyzed. The effect of a large difference be tween the fundamental frequencies is demonstrated as well as the influence of the dynamic friction coefficient for lengthening the plateau of the effi ciency curve. All these results can be used to improve numerical methods of resolution. (C) 1999 Academic Press.