Abstract: Dynamic stress and fatigue strength of a crankshaft of diesel engine with four cylinders is studied with consideration of the elastic deformation of bush. Special software ADAMS and ANSYS, assisted by self-designed programs, are adopted to solve the problem. The dynamic pressures of oil film in the bearings are obtained by analysis of dynamics and tribology of the crankshaft-bearing system with consideration of bush deformation. Programming language APDL in ANSYS is adopted to compile program for realizing the force boundary condition, then the dynamic stress on crankshaft journal surfaces is calculated. The fatigue strength of crankshaft is calculated by using damage accumulation theory. It is shown that the minimum thickness of oil film decreases and the maximum pressure of oil film increases to a great extent if the elastic deformation of bush is taken into consideration. The dynamic response and stress of crankshaft vary and the fatigue life of crankshaft decreases by 15.6%.

Key words: Crankshaft-bearing system, Damage accumulation theory, Deformation matrix, Dynamic pressure of oil film, Elastic deformation of bush