Dynamic Analysis And Fatigue Life Prediction Of Mud Pump Power End

Mud pump is an important part of mechanical equipment in the field of mechanical engineering drilling and is widely used in petroleum drilling.Mud pump mainly plays the role of circulating mud,cooling drill bits and transferring debris back to the ground.With the emergence of deep wells and ultra-deep wells and the increase of drilling depth,the requirements for the power and pressure of mud pumps are more and more high,and mud pumps are constantly developing towards the direction of high power and large displacement.At the same time,people pay more and more attention to the service performance and service life of mud pump due to the complex and bad field working conditions of mud pump.Connecting rod and crankshaft are the core components of mud pump power end.Its structural parameters,structural strength and fatigue life determine to a great extent the size and weight of mud pump,bearing capacity and service life.Under the repeated continuous action of cyclic load,the parts of mud pump are prone to fatigue failure,but this failure form has the concealment,until the damage accumulates to a certain degree of qualitative change,causing sudden fracture and destruction.Causing serious consequences and economic losses.In order to prevent accidents,the dynamic analysis and fatigue life prediction of the main parts of mud pump power end are very important.The movement and force of crank and connecting rod mechanism at the power end of mud pump are analyzed by using the knowledge of theoretical mechanics,and the variation and motion law of the force acting on each component in a period are shown intuitively by drawing the graph.The finite element model of mud pump power end is established by using finite element software ANSYS.The main structure of mud pump power end is analyzed statically to find the position where stress concentration is easy to be produced and the maximum stress is calculated.In order to reduce the real working condition of the mud pump power end better,the crank and connecting rod should be regarded as the flexible body,and the rigid-flexible coupling model of the mud pump power end should be created by using the ADAMS dynamic software.The dynamic stress state of connecting rod and crankshaft is analyzed by dynamic simulation of connecting rod and crankshaft.It is easy to produce fatigue damage when the crank of connecting rod is subjected to the repeated action of cyclic alternating stress,and the damage accumulates to a certain extent will lead to the damage of parts.The fatigue life of connecting rod and crank is analyzed and forecasted by MSC.fatigue software.The shortest fatigue life before failure is found,and the minimum total stress cycle times are calculated.The results show that,for the connecting rod,there is a relatively serious stress concentration at the transition corner between the rod body and the big end of the connecting rod,while for the crankshaft,There is a relatively serious stress concentration in the transition corner of the left and right spindle neck,which is the most dangerous part of the connecting rod crankshaft.Although the maximum stress values of the connecting rod and crankshaft are far less than their material yield strength limit,fatigue failure will still occur under the long cyclic load,resulting in the sudden fracture of the parts.With serious consequences and economic losses.The simulation results of the crankshaft and connecting rod are consistent with the actual situation,which lays a foundation for the design and improvement of the connecting rod and the crankshaft.