Nonlinear Vibration Analysis and Optimization of a Six DOF Passenger Train with Dynamic Absorber on the Primary Resonance Mode and Using Genetic Algorithm Method

Designing the suspension systems has been investigated as a major challenge to eliminate the undesired effects in the vehicles. Dynamic analysis of a nonlinear six degree of freedom (DOF) suspension is investigated in the present paper. Dynamic equation of motions of the wagon which is consisted of the wagon main body and two bogies were obtained using Lagrange method and then the primary resonance mode frequency response equation under external excitation is derived by solving nonlinear equations through multiple time scale method considering six DOF for wagon vertical movement. A dynamic vibration absorber system is used to passively control and minimizing the primary resonance vibrations of nonlinear system. The frequency response equations of the system were then compared either with or without dynamic absorber. Using a genetic algorithm, which is based on a random driven process, the best performance of the dynamic absorber suspension of the wagon in a six DOF system is investigated. During the process of solving nonlinear equations and optimization, a harmonic input with very small amplitude was assumed as input exerted on one of the wheels.