Non-linear dynamics of a whole vehicle finite element model using a harmonic balance method

Abstract

The aim of this paper is to apply the Harmonic Balance Method (HBM) to a finite element model of a complete vehicle (body, engine and engine mounts) to calculate the non-linear response of the assembly. The non-linear effects come from the amplitude-dependent stiffness of the engine mounts. First, the HBM is presented. A condensation process on the non-linear degrees-of-freedom is also proposed. This process reduces the original non-linear system by focusing only on the solution of the non-linear equations associated with the system’s non-linear components. Second, the engine mount stiffness dependency with amplitude is measured on a test bench to estimate a polynomial stiffness law. Finally, the numerical analysis is performed to analyse the non-linear response of the whole vehicle using the HBM algorithm with appropriate condensation located only on the non-linear coordinates of the system to minimise computer time.