Fretting Characteristics Analysis Of Connecting Rod Bushing Of Engine Based On ANSYS Thermo-mechanical Coupling

Connecting rod bushing is always connected with connecting rod by interference fit. When engine works, fretting usually happens between the contact surface of the interference fit. Fretting can cause the decrease of amounts of interference and rotation of connecting rod bushing; Besides, oil hole position could also change because of fretting, leading to bad lubrication and even the lock of piston pin. On the base of the actual engine operating situation, this paper utilized the finite element technique to research fretting characters of interference fit of connecting rod bushing, which has great significance and application value.Taking advantage of 3-D design software, this paper established the CAD model of the connecting rod bushing’s assembly, and then the finite element model was established by importing the model into FEA software ANSYS and mesh. And then realized the thermo-mechanical coupling based on the thermodynamics and the actual load of temperature and mechanical. And contact analysis was realized by setting appropriate contact parameters. Equivalent stress and contact pressure were got from the thermo-mechanical couple model when only considering the interference situation. The accuracy of the FEA model was proved by the comparation with the theoretical value. And when comparing with the results of FEA model without consideration of temperature, it’s found that temperature can cause higher equivalent stress and contact pressure.By fixing other parameters and changing one parameter, the influence of connecting rod angles, amounts of interference, friction coefficient and temperature on the fretting characters was analyzed. And contact pressure, friction stress, fretting amplitude and frictional work were got from the analysis. It’s found that the fretting is most serious when connecting rod angles is zero. Along with the increase of amounts of interference, fretting amplitude shows reducing trend, but friction stress, contact pressure and frictional work show increasing trends; With the increase of the friction coefficient, bushing contact pressure only changes a little which can be ignored, friction stress and frictional work increased, but fretting amplitude decreased. With the increase of the temperature, contact pressure, friction coefficient and frictional work shows a little increased trend, and fretting amplitude decreased. According to the analysis, some measures were offered to reduce the fretting.