Study On The Detection And Energy Feature Extraction Method Of Friction Vibrations During Reciprocating Sliding Running-in Wear Process

Running-in is the process of tribological pairs from its original state to operating status,and its quality directly affects the operating condition of tribological pairs.Friction vibration is a physical phenomenon generated by surface asperity contacts of tribological pairs during the running-in wear process,and it is one of the tribosystem characteristics that can provide the tribology and dynamic information of tribological pairs.Therefore,the study of the friction vibration can provide a new solution to research the Tribological Testing Technology and Tribosystem Condition Identification,which is important for both the running-in wear property evaluation of tribological pairs and the tribological design.Studies of the detection and an energy feature extraction method of friction vibration were carried out to research the Tribological Testing Technology of tribological pairs by the friction vibration with the acquired vibration signals during the reciprocating sliding running-in process,and the verification of the detection and energy feature extraction method of friction vibration were conducted with running-in wear experiments under different conditions.The main contents are as follows,1.According to the mechanical description of friction vibration,tangential and normal friction vibration are excited by the same source simultaneously.In this manuscript,the research of the correlation between tangential and normal friction vibration was carried out with reciprocating sliding friction and wear experiments of tribological pairs.Result shows that tangential and normal friction vibration are high cross-correlation signals of the same source.2.According to the correlation between tangential and normal friction vibration,a detection method of friction vibration was established with the application of harmonic wavelet packet transform(HWPT)and cross-correlation theory,and it was analyzed by running-in wear tests.Results show that tangential and normal friction vibration signals that extracted with the HWPT and cross-correlation theory are high cross-correlation signals of the same source and they both show significant regularities.The amplitudes of both tangential and normal friction vibration appear almost the same trend with friction coefficient,which reflect the transformative processes of tribological pairs from the running-in wear to the stable wear.Hence,the friction vibration detection method can be achieved with the combination of HWPT and cross-correlation theory.3.To quantitatively reveal the evolution of the running-in wear process of tribological pairs,the tangential and normal friction vibration was integrated with a vector synthesis algorithm,then an energy feature parameter K that can reflect the phase-space volume of synthesized friction vibration attractor was extracted with phase-spacereconstruction theory and singular value decomposition method,and the variation of the energy feature parameter K was analyzed by the running-in wear test of tribological pairs.The result shows that when triobological pairs are severe,synthesized friction vibration attractor is large in phase-space volume and the energy feature parameter K is large.On the contrary,the phase-space volume of synthesized friction vibration attractor is small and the energy feature parameter K is in low value.Hence,the energy feature parameter K reflects the variation of the phase-space volume of synthesized friction vibration attractor and reveal the evolution of the running-in wear process of tribological pairs quantitatively.4.To verify the detection and energy feature extraction method of friction vibration,running-in wear experiments under different conditions were carried out with the change of load,sliding velocity,original surface roughness and tribological pairs material.Results show that,both the running-in process and the running-in quality of tribological pairs varied with the change of experiment conditions,that is,the running-in wear property is different.Friction vibration reflects the variation of running-in wear property of tribological pairs under different test conditions,(1)the amplitude of synthesized friction vibration signals and energy feature parameter K show the same trend with friction coefficient during the running-in process in each test,which reflect the transformative processes of tribological pairs from the running-in wear to the stable wear,and(2)when the worn surface roughness of tribological pairs after test under different running-in wear conditions gets smaller,the running-in wear property becomes better and the energy feature parameter K gets smaller,on the contrary,the running-in wear property gets worse and the energy feature parameter K becomes larger.Therefore,the energy feature parameter K reflects the change of running-in quality of tribological pairs under different running-in wear conditions.