Finite Element Analysis Of Automobile Engine Crankshaft And Study On Its Casting Process And Mechanical Property Of Ductile Iron

Ductile iron has many excellent performances such as high strength,high toughness,well damping performance,low production costs and so on.So it has been widely applied in automobiles,heavy equipments,railway equipment and other fields.Casting instead of forging and ductile iron instead of steel can save production costs and meet the needs of automobile parts weight loss design.Virtual prototyping simulation and finite element simulation technology applied to product design can save experiental costs and shorten the product research and design periods.In this paper,the virtual prototype simulation and finite element simulation analysis technology were applied synthetically at the early stage of crankshaft structure design,Rapiding crankshaft research and design speed with simulation instead of experimental testing and to ensure the rationality of the crankshaft structure design.Developing high performance casting ductile iron crankshaft to replace the traditional forged steel crankshaft,to save cost and achieve lightweight design goals.In this study C10T engine crankshaft product was used as a investigation object.Firstly,the material properties of the crankshaft were put forward by static strength finite element analysis,and then designed and optimized casting process and alloying elements composition of crankshaft,Developed high performance ductile iron to meet the mechanical properties of crankshaft material requirements.Based on virtual prototype multi-body dynamics simulation and finite element simulation analysis,the results show: The crankshaft is subjected to the greatest stress during ignition outburst of each engine cylinder,The maximum von mises stress values respectively were 100.9MPa,117.3MPa and 98.21 MPa.The results of strength analysis showed that the crankshaft static strength and fatigue strength meet the design requirements.Flow field and temperature field in mold filling and solidification process of crankshaft casting were simulated and analyzed based on Anycasting.The results suggested that the existence of hot spots at the journal and easy to appear shrinkage porosity.By adding indirect cold iron could eliminate hot spots and shrinkage defects,improve casting crankshaft quality and pass rate.High-performance ductile iron was developed by adjusting addition of the alloying elements Cu and Mn.Adding weight percentage of 0.85%~1.15% Cu and 0.2%~0.45% Mn,the tensile strength of ductile iron crankshaft body specimen achieved 820MPa~930MPa,elongation reached 4% or more.which achieved and exceeded the performance standard of QT820-3 and satisfied the mechanical properties requirements of crankshaft.