Study On Friction And Wear Properties Of PEEK And CF/PEEK

Polyether ether ketone(PEEK)and its carbon fiber reinforced composites(CF/PEEK)have been widely used as a wear-resistant material in many fields such as aerospace and automotive because of their outstanding friction and wear properties.In this paper,the friction and wear patterns of PEEK and 30% CF/PEEK injection products were studied based on the high temperature end-face friction and wear test.Combined with ABAQUS software,the wear simulation and prediction were realized.(1)Firstly,the influence of different experimental conditions(pressure×friction speed,PV)on the wear rate of PEEK and 30% CF/PEEK injection molding products was studied based on the high temperature end-face friction wear test.The experimental results show that the wear rate of PEEK increases with the increase of PV in approximately quadratic function,and the wear rate of 30% CF/PEEK decreases with the increase of PV and has a approximately inverse relationship.When PV is greater than 0.4 Pa·m/s,the wear of PEEK begins to exceed 30% CF/PEEK,and the difference increases with the raising of PV.Based on the above rules,a modified Archard wear calculation model of PEEK and 30% CF/PEEK was established by data fitting using MATLAB software.Based on the proposed wear model and combined with the ABAQUS subroutine Umeshmotion,the wear of PEEK products was numerically simulated.The simulation results of the average wear depth in a certain range of PV are in good agreement with the experimental results,but with large PV or at high temperatures the wear prediction will has an obvious deviation.(2)Secondly,in order to establish a wear model considering both the friction condition and the contact temperature,the initial temperature,pressure and friction speed are simultaneously treated as experimental variables for friction and wear experiments.The experimental results show that the wear of PEEK and 30% CF/PEEK increases with the initial temperature.Because the thermal conductivity coefficient of PEEK material is relatively low,the contact surface temperature during the friction process under high PV conditions will be significantly higher than other locations.The existing experimental conditions cannot measure the contact surface temperature.Therefore,the temperature field of the friction process was simulated by ABAQUS software and compared with the experimental temperature,which verified the rationality of temperature field simulation method in this paper.Then the average temperature of the contact surface during the simulation was extracted,together with the experimental PV and the measured wear amount,with which amodified Archard wear calculation model considering the contact surface temperature of PEEK and 30% CF/PEEK was established.(3)Finally,the simulated frictional temperature field was introduced into the ABAQUS software as a predefined field for sequential thermal coupling analysis.At each analysis step,the temperature field,contact pressure and relative slip of the contact surface node were extracted into the modified Archard wear calculation model that takes into account the contact surface temperature,and the corresponding wear depth of the node was calculated.Then,the model was updated.The process was repeated to achieve wear accumulation until the total grinding-process was reached.The simulated wear depth is in good agreement with the experiment,which shows that the wear model and the numerical simulation method proposed in this paper are reasonable and suitable for wear prediction of PEEK and 30% CF/PEEK under complex contact conditions.