| Mud pump is an essential equipment of oil drilling units,which is characterized by wild medium transported,high pressure and high efficiency.During the drilling operations,mud pumps are towards lager cylinder bore,lager power,longer stroke and higher pump pressure with the deepening of drilling depth.As a significant equipment of oil production,the performance of mud pump has an important impact on oil production.Therefore,it is of great significance to improve the research and design level of homemade five-cylinder mud pump and to enhance the performance and quality of domestic equipment.The crankshaft system at the dynamic end of mud pump,whose structure and fatigue strength could directly influenced reliability,service life and the safety of production of mud pump,is the most critical part of mud pump.While mud pump working,the crankshaft is subject to a cyclic alternation load which occur stress concentrations,leading to fatigue failure,resulting in production safety accident and large economic loss.So this paper optimized the structure of crankshaft by co-simulation of AMESim and LMS virtual Lab Motion to reduce the maximum stress force and to improve its service life and safety.A five-cylinder mud pump with high power and displacement was researched in this paper.The principle of dynamic and motion of mechanical system,computer programming and co-simulation technology is applied to analysis the crankshaft,the specific research contents and achievements including the following aspects:(1)Firstly,the general scheme of mud pump was determined and its top-level skeleton model was built by Creo,using the top-down methodology.Then the overall model was created upon the top-level skeleton model.The parameters of mud pump was designed in Mathcad and was transferred by seamless connection between Mathcad and Creo,which could rapidly transform designed parameters into geometry dimensions of virtual model.(2)A mechanical analysis was made,and deduced the computational formulas of inside and outside force,section stress and the popular methods for checking the strength and rigidity.(3)The crankshaft system,cylinders,valves and other components were established in AMESim simulation model,which composed into a 1D model of mud pump.The hydraulic pressure on piston and the fluctuation characteristics of working flow and pressure of mud pump was gained by simulation analysis and compared with the theoretical value,verifying the accuracy of the mud pump model built in AMESim.(4)Based on the co-simulation of LMS Virtual.Lab Motion and AMESim,rigid-flexible coupling kinematics and dynamics simulation was carried out to obtain the kinematics characteristics of all components,the motion property of piston,dynamic features of force on crank pin and main journal and the stress distribution conditions of crankshaft.(5)According to the stress distribution conditions of crankshaft,a fillet with stepped appearance was designed to reduce stress on crank pin.Aimed at the lowest stress on the fillet,an optimized model with design factors of R1,R2,and H was established on the basis of RSW(Response Surface Methodology).The solving result showed that the stress on the fillet lowered 20.64 percent with the optimum solution. |
