Studies On Fretting Contact Numerical Analysis Based On Conjugate Gradient Method And Fast Fourier Transform

Fretting contact has been a very important part in tribology and has been already got the attention of the scholars at home and abroad.Fretting contact is widespread in many industries such as machinery industry,bridge industry and automobile industry.The investigation of fretting contact and fretting wear play an important role in improving the component operating conditions and prolong the service life.In this dissertation,the fretting contact theory has been presented.The fretting contact with rough surface and fretting wear with coatings are investigated by combining Conjugate Gradient Method(CGM)and fast Fourier transform(FFT).The parallel method is used to recompose the fretting contact program.Via the investigation,a certain theoretical reference can be proposed in fretting contact and wear phenomenon during the practical projects.Firstly,the homogenous fretting contact model with rough surface in this thesis,and the pressure,tangential stress and the distribution of slip and stick zone of single asperity,sinusoidal wave and roughness are analyzed.The results indicate that the amplitude of the surface has an impact on tangential load-displacement curve and the energy dissipation during the contact.The tangential displacement caused by the same tangential load and the energy dissipation will increase with the surface amplitude.Secondly,the fretting wear model with coatings is established on the basis of investigation of fretting contact.The important parameters such as wear morphology and load-displacement curve are studied during different wear process and this research is divided into smooth surface and sinusoidal surface.The results indicate that the fretting wear will generate on the slip zone which has relative slip rather than stick zone.In sinusoidal surface contact,each single asperity has its own local slip zone and local stick zone,and the fretting wear will generate in each single asperity.The stress on local slip zone has the same discipline as smooth surface.In order to decrease the running time of fretting contact computing program,the parallel method is used in this paper to accelerate.By means of parallel recomposing to FFT module,running time of fretting contact program can be decreased efficiently.The running time of fretting contact program will decrease with the thread number increasing and the thread number equal to 3 will be the best solution for the FFT and fretting contact calculations.