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.

当旨在实现高安全标准和低排放以实现环境可持续性时，客车的动态评估是最重要的。这项工作在考虑其模态分析的情况下研究了公共汽车的动态响应，为此开发了简单的动态模型以快速确定最低频率，主要来自悬架灵活性。此外，通过有限元方法 (FEM) 建模计算无法使用简化模型确定的复杂固有振动模式。为了研究轮胎弹性行为，作为车辆和道路之间的关键环节，开发了特定的变形模型，导致刚度矩阵与每个车轮/轴的车辆弹簧悬架的刚度矩阵相结合。本研究旨在提出一套数学公式来详细描述客车的模态行为，这些公式可以适用于具有类似条件的任何其他长车。研究了两个主要因素，即悬架和轮胎变形效应。在用于评估固有频率和相关模式的简化方法和 FEM 模型结果之间验证了可接受的一致性。