Fatigue Reliability Analysis And Fatigue Life Prediction Of High Pressure Jet Mud Pump

The crankshaft and connecting rod are the most important parts of pump power end,its structural parameters determines the size and weight of the whole mud pump, itsstructural strength determines the overall carrying capacity of the mud pump, the fatiguelife determines the entire pump’s fatiguelife. Crankshaft and connecting rod prone tofatigue failure under repeatedly alternating load at work. Because there is no obviousmacroscopic plastic deformation due to fatigue damage, abrupt fatigue fracture oftenhappens when the damage reaches a critical state, it can cause a catastrophic accidentand huge economic losses. Therefore the analysis of fatigue strength and fatigue life ofcrankshaft and connecting rod plays important roles in preventing fatigue fractureaccident and improving working life of mud pump.In this paper, force curve of crankshaft and connecting rod has been obtainedduring imbibition and flowing back cycle, through force analysis of mud pump powerend using rigid body plane kinematics theory, and three-dimensional geometric modelof crankshaft and connecting rod has been established by using software PROE, and thestatics, modal and dynamics of flexible multi-body analysis has been carried out,dangerous areas of crankshaft and connecting rod have been found out, the stress-timecurve through dynamics simulation has been achieved. On this basis, the fatiguereliability analysis of crankshaft and connecting rod has been carried out using fatiguereliability design theory, fatigue life analysis has been pointed out by using SoftwareMSC.Fatigue. Finally measures of improving fatigue life of crankshaft and connectingrod have been discussed according to its design process and fatigue fracture accidentthat happened in the engineering practice.Simulation result shows that there are more serious stress concentration at the filletof the connecting rod big end and body, crankshaft main journal fillet, and stress atstress concentration is much smaller than the yield strength of the material, so it cansatisfy the requirement of static strength design, but under repeatedly alternating stress,the stress concentration areas prone to fatigue failure, where crankshaft and connectingrod fatigue reliability and fatigue life is the lowest, which determines the overall fatiguereliability and fatigue life of the crankshaft and connecting rod.simulation result is in good agreement with common fracture area of crankshaftand connecting rod in the engineering practice, and the correctness of simulation resultare proved, which provides the basis for further design and improvement of crankshaft and connecting rod.