Study On Friction And Wear Analysis And Energy Dissipation Of Elastoplastic Contact On Rough Interface

With the continuous breakthrough of independent innovation in mechanical equipment manufacturing,high-end equipment will face more complex and severe service conditions,and the joint interface performance of mechanical equipment will become a key scientific and technological problem restricting the future development of the equipment.Therefore,faced with the increasingly complex operating condition and higher standard performance requirements,the accurate prediction and control of the contact behavior of the interface is the basis and key to the development of high-end equipment.The tangential action model of mechanical interface is essentially a friction model.Due to many factors affecting the friction performance,the universal contact theory of mechanical interface has not been formed.Moreover,in the study of the dynamic and static characteristics of the interface,there are more qualitative research methods of experimental measurement and less quantitative research methods of theoretical calculation.Thus,the purpose of this paper is to improve the contact theory of interface,establish non experimental fitting friction and wear models,and verify the effectiveness of the theoretical models experimentally.The main contents of this paper are as follows:(1)Based on the real rough topography of the interface,a digital simulation method of the surface profile is proposed.The unified power spectral density in space domain is defined mathematically,and the extension standard of filter sequence and the phase angle range of transfer function in time domain are derived,so as to obtain the digital rough surface which meets the requirements of fractal dimension,profile height distribution and autocorrelation function.On this basis,the dimension and noise reduction of the digital surface are carried out by coordinate transformation and wavelet theory,and the surface profile of different scales are extracted.(2)Considering the elastoplastic deformation and relative sliding of the interface,a multi-factor coupling wear model is established.Based on the return-mapping algorithm,the Newton-Raphson iterative method is used to solve the elastoplastic stress of the contact body.Then,a normal contact model considering a multi-factor coupling is established based on the Johnson’s compatibility equation and the Archard’s wear law.The return-mapping algorithm and the conjugate gradient method are combined to solve the pressure distribution and wear morphology of the interface.The effectiveness of the model is verified by ring-block wear experiments.(3)Based on the measurable surface topography and material properties,a cross scale fretting model without experimental calibration is proposed.The slip index is introduced to quantitatively describe the contact state and operation condition of the interface,and the parallelogram envelope is used to determine the main characterization parameters of fretting.Based on the macro scale phenomenological model and the characteristics of the gross slip condition,an Iwan solution of the micro scale phenomenological model is obtained,and then a cross scale tangential fretting model is derived.Then,the initial tangential stiffness,energy dissipation,slip index and other fretting characteristic parameters of the interface are calculated by using the proposed model.(4)Based on the study of the tangential action of the interface,a quantitative model of multi topographical parameters is proposed.By using Pearson system,the probability density function satisfying the requirements of arbitrary surface topography with good computational performance is derived.On this basis,a dimensionless tangential contact model coupled with multi topography parameters is established.Then,the law of profile height distribution changing with surface roughness is revealed by mathematical method,and the influence of topography parameters such as the plasticity index,skewness and kurtosis on the contact performance of the interface is quantitatively analyzed.(5)Aiming at the concealment and difficulty of the observation of the interface,a high-precision tangential contact experimental platform based on the direct method is developed.The driving device,measuring device and data acquisition device are selected to meet the requirements of the experimental design,and the plane/plane tangential contact experimental platform is built.After the calibration experiment of the platform is completed,the quasi-static experiment and the fretting experiment are used to observe the influence of residual stiffness,new interface,wear,surface topography,excitation conditions and other factors on the contact performance of the interface,so as to verify the effectiveness of the theoretical models.