Simulation and Analysis of Thermo-Mechanical Coupling Load and Mechanical Dynamic Load for a Piston

Engine pistons are one of the most complex components among all automotive. In this paper, a 1/2 3-D solid model including piston and piston pin of a new designed piston was established by Pro/E software, and the finite element analysis model was also established by using ANSYS software. The thermo-mechanical coupling stress distribution and the deformation were firstly calculated. Considering the nonlinear material properties of piston and piston pin, the Newton-Raphson equilibrium iterative method is applied. In the calculation, the contact forms of forces and the relative movement between piston and piston pin are described with contact pairs and analyzed with the augmented Lagrange method. Calculating results indicates that the maximum stress concentration is at the upper end of piston pin boss inner hole, and is mainly caused by the peak pressure of the fuel gas. Then the finite element mechanical dynamic analysis was conducted Considering the mechanical fatigue testing method, the Newmark time integral algorithm of transient analysis full method are applied to calculate the dynamic responses, and the mechanical fatigue life-span was calculated, which is rather corresponded with the experimental. All these analysis indicate that the design of the piston is reliability.