Crankshaft Stress Analysis Procedures in the Engine Design

Two analysis procedures of the crankshaft stress are introduced. One is the conventional method which is very efficient as a model of simple beam at initial design stage within short time. For this analysis bending and torsion are considered as loadcases that are subjected to cyclic variation. The other is the detail Finite Element Analysis which is taken into account of load conditions due to the complex crankshaft dynamic behaviors. From the analysis, the natural frequencies in torsion and bending of the crankshaft as well as with the associated mode shapes and the maximum moments are calculated. The maximum moments are used in FE analysis as loadcases. The model is completed using solid linear elements with some special elements. The application of the FE method for the crankshaft stress analysis has advantage as it directly supplies the locations and level of maximum stresses, even though this method reqiures exact boundary conditions and spending much time in calculation.