Coupling Analysis Of Multi Flexible-Body Dynamics And Hydrodynamic Lubrication Of Crankshatf System

Crankshaft is one of the most important components of theengine, which endures the impact of the alternating load andis in poor condition when working. The performance of thecrankshaft which is decided by the loading conditons anddynamic lubrication conditions of the main bearing directlyinfluences the service life and operational reliability of the engine.Therefore, it has great significance to study the influence ofthe loading situation and dynamic lubrication of the mainbearing on the crankshaft system.A method that combined the finite element method withmulti-body dynamics is applied to set up the multi-bodydynamics model of the crankshaft system, and then it canresearch the dynamic simulation of the crankshaft system.First of all, the multi-body dynamics model of thecrankshaft is created and the simulation is calculated,which are based on the LMS Virtual. Lab Motion. According to the result of the displacement, speed and acceleration of thepiston in the simulation, the accuracy of the model isproved. It uses Hypermesh which is the finite elementmeshing software to mesh the crankshaft and exports theflexible file.BDF, which is used to replace the rigidcrankshaft of the model.the Craig-Bampton modal of the crankshaftwas calculated by Nastran which was driven by the software Motion andis used to establish the rigid-flex coupling dynamic modelof the crankshaft. Comparing the main bearing loads of therigid model and the rigid-flex model of the crankshaftsystem by the simulation result of the dynamic model, thecharacteristics of the main bearing loads can be obtained.Secondly, the simulation of main bearing lubrication was carriedon to the crankshaft system, and then the lubrication conditionof the main bearing is analysed by the result of the minimaloil film thickness, the maximal oil film pressure, thefriction loss power and orbital path in two working cycles,which is extracted from the simulation of the main bearinglubrication. By capturing the continuous pressure distribution of the oil film in different time, it cananalyse the lubrication condition of the oil film when thecrankshaft is tilting. Comparing the change of the bearinglubrication characteristics between the rigid crankshaft andthe flexible crankshaft, it is turned out that it isnecessary to consider the influence of the elasticdeformation of the crankshaft when coupling Simulation of multiflexible-body dynamics and hydrodynamic lubrication of crankshaftsystem.Finally, this paper discusses the influence of differentbearing clearance and lubricating oil pressure on thelubrication performance of the bearing, makes somesuggestions on improving the lubrication performance of themain bearing and provides reference for the engineeringpractice.