Dynamic Modal Analysis of a Passenger Bus: Theoretical and Numerical Studies

Document Type

Journal Article

Publication Date


Subject Area

mode - bus, planning - environmental impact, planning - methods, planning - safety/accidents, infrastructure - vehicle


Deformation, Dynamic models, Finite element method, Mathematical models, Modal analysis, Suspension systems, Tires, Transit buses


The dynamic assessment of a passenger bus is of the highest importance when aiming at high safety standards and low emissions for environmental sustainability. This work studies the dynamic response of a bus considering its modal analysis, for which simple dynamic models were developed for fast determination of the lowest frequencies, mainly arising from the suspension flexibility. In addition, complex natural vibration modes, impossible to determine using simplified models, were calculated via finite element method (FEM) modeling. To study the tire elastic behavior, as the key link between the vehicle and the road, specific deformation models, leading to a stiffness matrix to be combined with that of the vehicle spring suspension at each wheel/axis, were developed. This study aims at proposing a set of mathematical formulations to describe the modal behavior of passenger buses in detail, which could be applicable in any other long vehicle with similar conditions. Two main factors are studied, namely the suspension and the tire deformation effect. An acceptable agreement was verified between the simplified approach and FEM model results for the evaluation of natural frequencies and associated modes.


Permission to publish the abstract has been given by SAGE, copyright remains with them.