Experimental Study On The Correlation Between The Contact Resonance Frequency And Friction-induced Noise Frequency

Friction-induced noise is a kind of important environmental noise and has significant influence on our work and life. In recent years, many researchers have paid close attention to the research on friction-induced noise. Since, the friction-induced noise is caused by self-excited vibration and there is no direct information for identification, its generation mechanism remains partially unknown. So far, friction-induced noise can not completely eliminated by technological methods all around the world. Therefore, the study on friction-induced noise still has a high academic value and an important application value.In this paper, a series of experimental tests are carried out to study the correlation between the contact resonance frequency and friction-induced noise frequency. Based on Rhee’s hammering-excited mechanism, the following conclusions are obtained:(1) A series of noise test were carried out using a pin-on-disc friction system. The results show that low level noise occurs in the most of each circular ring scar. On the contrary, squeal noise occurs in a small area of each circular ring scar on the disc and lasts for a short time. The frequencies of two noises are identified by the power spectrum analysis. It is found that squeal noise has a higher frequency than moan does. The squeal noise frequency is close to the contact resonance frequency of the friction system.(2) Moan and squeal signals acquired in the reciprocating sliding system are analyzed using wavelet decomposition. The results show that the frequency components of the moan signal are different from those of the squeal signal. The frequency of the moan signal covers a large frequency band and the frequency of the squeal signal covers a relatively higher frequency band. The singularity analysis of friction-induced noise signal shows that with the increase of decomposition layers, high-frequency components become fewer and its developing trends become ever more obvious. The discontinuity point is nearby the break of frequency and amplitude.(3) A series of experimental tests on the correlation between the contact resonance and friction-induced noise were carried out using two ball-flat friction pairs on a reciprocating sliding tester. The test results indicate that the contact resonance frequency of the friction system is very close to the frequency of friction-induced noise, whose relative errors are almost less than2～5%.(4) In order to find the reason for contact resonance frequency being close to the frequency of friction-induced noise, the scanning electron microscope is used for observing the topography of the worn surfaces. The results indicate that the mechanism may be attributed to the interactive action between the asperities on one friction surface and those on the other friction surface. The interactive action leads to friction force intermittent and pulse characteristics. The friction force in the presence of squeal noise is decomposed by using wavelet. The results show that the dynamic component of friction force with squeal noise mainly covers a higher frequency band, the more high-frequency energy of friction force, the larger incentive effect on friction systems, the friction systems will appear resonance phenomenon and induce squeal noise when high-frequency components of friction force being close to the inherent frequency of friction systems.