CAE Analysis Of Fatigue And Durability Study For The Internal Combustion Engine Piston

Piston is the core component of an internal combustion engine which is often fatigue damage for its poor working conditions. This results in a serious impact on the reliability of the internal combustion engine and becomes a weak link in its further development. To solve these problems, on the basis of heat transfer theory and fatigue theory, this paper studies the piston from three aspects which is including thermal-mechanical coupling analysis, reliability design and fatigue life prediction. And this will help to study the structural design and reliability of piston.This paper studies piston mainly from the following aspects and all of these will be based on ANSYS which is one of the finite element analysis software.(1)First, empirical or semi-empirical formula is used to calculate the thermal boundary conditions of piston and piston temperature field is simulated through ANSYS software. Then, the calculated and measured values of piston temperature are compared. With this method, the measured temperature is used to modify the thermal boundary conditions of the piston. Finally, the piston temperature field in calibration conditions is obtained.(2)Thermal stress and strain field, mechanical stress and strain field and thermo-mechanical coupling stress and strain field are got through CAE analysis. The key factors which have an effect on the reliability of piston are obtained. And the effects of diameter of pin seat, height of firepower shore and axial position of cooling oil cavity are analyzed. All of these are the basis of reliability design and fatigue life prediction.(3)The orthogonal experimental design method is used in this paper. The diameter of pin seat, the height of firepower shore and the axial position of cooling oil cavity are selected as controlling factors of design variables, and three values of the various factors are set to the level. The orthogonal table arranged in 9 groups experimental program is used to optimize the design. On the basis of experimental results of the nine groups, the poor value, the F statistic and the orthogonal variance table are calculated to study the effect of various factors. And ultimately, the optimization method which can enhance the reliability of the piston fatigue is obtained.(4)The simulation results of optimized piston will be import to specialization fatigue life analysis software nCode DesignLife with the fatigue load information and the material fatigue properties to simulate the fatigue life of piston and to analyze the results of the fatigue life prediction.