Fatigue strength detection method for crankshaft of vehicle internal combustion engine based on dynamics

To accurately determine the load boundary conditions required for the finite element calculation of crankshaft fatigue strength, a dynamic-based fatigue strength detection method for the crankshaft of the automotive internal combustion engine is proposed. Taking a certain type of automotive internal combustion engine as the research object, the multi-body system dynamics model of crank-connecting rod mechanism is established and the dynamic load spectrum of a crankshaft in a working cycle of the internal combustion engine is obtained through dynamic simulation analysis. The load boundary conditions of crankshaft finite element analysis are obtained and the finite element model which can simulate the contact state between crankshaft and bearing is established. The crankshaft fatigue strength is based on the dynamic load spectrum. Degree detection provides load boundary, the fillet sub-model is constructed and the stress distribution of the fillet sub-model under 12-unit displacement loads is obtained by calculating the stress field. The working fatigue safety factor of the crankshaft under dynamic stress is calculated. The analysis results show that the detection error of the proposed method is less than 5% under different noise intensities and the average energy consumption is lower than that of the comparative detection methods, which are 251.37 J and 617.37 J respectively and shows that the proposed method has strong anti-interference and low energy consumption. © 2021. MechAero Foundation for Technical Research & Education Excellence.