Crankshaft fatigue research based on modified multiaxial fatigue model
                                                           SUN Songsong1, WAN Maosong1, WANG Hui2
（1.College of Automobile and Traffic Engineering, Nanjing Forestry University, Nanjing 210037, China;2.College of Mechanical Engineering, Nanjing Institute of Technology, Nanjing 211167, China）

Abstract: In order to research the crankshaft bending fatigue property, the McDiarmid multiaxial fatigue model was applied to predict the fatigue limit load of the crankshaft. First the stress state of a crankshaft under a bending load was analyzed and the fatigue style was determined to be the multiaxial fatigue, then the critical plane, the shear and normal stress were obtained based on a coordinate transform method. Finally the fatigue limit load of a crankshaft was predicted by comparing the limit stress of another crankshaft made by the same material and corresponding experimental verifications were conducted. The results indicate that the conventional McDiarmid multiaxial fatigue model may result in some errors between the experimental results and the predictions in such prediction, while the stress ratio modified model can provide higher accuracy and is more suitable to be taken into the actual engineering application.

Key words: crankshaft; multiaxial fatigue; McDiarmid model; critical plane; damage model; model updating