Abstract: In this paper, HyperMesh software is used to establish a simulation model for the body in white of a commercial vehicle, study its natural frequency and vibration mode under free state, and carry out the modal test verification of the body in white. The test data are compared with the simulation analysis results. The frequency error of the finite element analysis and the frequency of the test results is within 5% except for the first order, which indicates that the finite element model is relatively accurate and the calculation results are reliable, The simulation results can well reflect the vibration characteristics of the actual structure. The overall modal frequency of the body in white is far from the second order unbalanced excitation frequency, which is less likely to cause vehicle resonance. The estimated vehicle comfort and vehicle fatigue life meet the requirements. The evaluation of structural characteristics by means of simulation can save the cost of development and test, shorten the development cycle and provide a theoretical basis for design.

Key words: Commercial vehicle; Body in white; HyperMesh; Modality study; Finite element analysis

摘要： 文章利用 HyperMesh 软件对某商用车白车身建立仿真模型，研究其在自由状态下的固 有频率及振型，并进行了白车身模态试验验证，将试验数据与仿真分析结果进行对比，有限 元分析的频率与试验结果频率除第一阶外，其他各阶整体主要模态的频率误差在 5%以内，说 明有限元模型比较准确，计算结果可信，仿真结果能够很好地反映实际结构的振动特性，此 白车身整体模态频率与二阶不平衡激励频率相差较远，引起整车共振可能性较小，预估整车 舒适性及车身疲劳寿命满足要求。通过仿真手段评估结构特性，可节省开发试验费用，缩短 开发周期，为设计提供理论依据。

关键词: 商用车；白车身；HyperMesh；模态研究；有限元分析