Dynamic analysis of vehicle propulsion group with nonlinear characteristics of supports and arbitrary motion of the car body

The propulsion group of a vehicle is considered as a rigid body with six degrees of freedom, subjected to arbitrary loading and support action. The propulsion group motion consists of the given car body motion and of the relative motion with respect to the car body. The support elastic characteristics are nonlinear and defined for the principal axes of each support. Viscous damping at the supports, proportional to the square root of the current stiffness of each support, is taken into account. The nonlinear differential equations of motion are derived without any simplification. Then, the Newton integration scheme is implemented and a system of incremental-iterative algebraic equations is formed. The only approximation adopted is neglect of products of the rotation increments in the current iteration. The developed software provides static, dynamic and frequency analysis for general description of nonlinear elastic characteristics of supports, car-body motion, damping and loadings. Some numerical examples, typical for the real working conditions of the propulsion group, are given to illustrate applicability of the developed methodology and software. Dynamic response which includes displacements and rotations, as well as the support reactions, are graphically presented in the paper.