Abstract
In this paper the finite element (FE) method was used for a numerical analysis of free vibrations of the airport bus structure type Eurobus AE 141 A. FE model and boundary conditions were determined. The eigenvalue problem was solved for two load cases: the bus structure fully loaded with passengers and the one without passengers. Modal analysis was carried out by means of three methods: Lanczos, simultaneous vector iteration (SVI) and Guyan reduction. SVI method was conducted with two options: frequency shift and definition of kinematic degrees of freedom (KDOF). Rigid body vibration modes of the bus were determined by taking into account elastic characteristics of the springs and inertial characteristics of the bus structure. On the other hand, elastic structure vibration modes were determined by the mass and stiffness of the bus structure.