Based on the theories of flexible multibody system dynamics and lubrication,the coupling model of piston,connecting rod and crankshaft was established.In the model,the absolute node coordinate frame was used to analyze the dynamic characteristics of the flexible multi-body.The average Reynolds equation and the asperity contact theory were used to describe the mixed lubrication and wear characteristics.The finite element method and backward Euler method were used to solve the equations in space and time,respectively.The lubrication,wear and fatigue characteristics of the connecting rod big end bearing of a marine medium-speed engine were calculated and analyzed.The results show that the relative velocity of the journal and bearing bush in the center of the bearing lubrication domain change regularly,and the mixed lubrication state mainly occurs around 90° after the top dead center of the combustion.The wear is concentrated on the edges of both sides of the 50° circumferent region of the upper shell of the connecting rod bearing.The maximum single-cycle wear amount of the flexible model is 1.7×10-6 μm,which is 20.5 times that of the rigid model,and the wear life is 1.1×104 h.The location of fatigue damage is the same as the location of wear,and the fatigue life is 7.8×104 h.
关键词
连杆大端轴承/混合润滑/磨损/疲劳/多柔体系统/有限元法
Key words
connecting rod big end bearing/mixed lubrication/wear/fatigue/flexible multibody system/finite element method
维普
万方数据