Vibration Fatigue Analysis Of Diesel Engine Exhaust Manifold

Diesel engine exhaust manifold is not the core component of the diesel engine, but it is the direct support of turbocharger. Its reliability is directly affects the normal operation of the turbocharger and even the entire diesel engine, which play a very important role in the performance of the diesel engine.This paper focuses on the study of the exhaust manifold which connect turbocharger and diesel engine. According to the analysis of the failure mode, it is found that the damage is rare in the static load condition, and the fatigue failure is the main failure mode.Through the analysis, it is found that the cause of fatigue failure is mainly due to the alternating impact load. Therefore, the finite element analysis of static strength is far from satisfying the design requirements, which must be studied in many aspects such as the dynamic response and fatigue strength.Firstly, use finite element pre-processing software ANSA to simplify the three-dimensional model of exhaust manifold. And then based on the theory of modal analysis and frequency response analysis, the modal method of frequency response analysis of the exhaust manifold is analyzed. The analysis results is imported into the fatigue analysis software of MSC.FATIGUE. The Drilik method was used to calculate the vibration fatigue life. The average stress was modified by Goodman method, the stress criterion was Mises von, and the design criterion was the survival rate of 50%. Mainly includes the time-frequency transformation of the load spectrum and its correlation processing and the generation of the fatigue characteristic curve. Through the analysis, we known that the vibration load of the turbocharger is the main cause of the fatigue failure of the exhaust manifold, and the maximum fatigue damage of the exhaust manifold is calculated, and the vibration fatigue life is predicted.Finally, The influence factors of vibration fatigue life are analyzed, which provides a theoretical reference for vibration fatigue design of the exhaust manifold. On the one hand, it can reduce the research and development costs, on the other hand, can greatly shorten the product development cycle and improve design efficiency.