毕业论文：《白车身模态分析试验方法研究》.docVIP

PAGE 目 录 TOC \o 1-3 \h \z \u 中文摘要 h 1 英文摘要 h 2 1 绪论 h 3 2 试验模态分析 h 5 2.1 模态试验理论 h 5 2.2 试验测试系统组成 h 6 3 模态参数识别方法 h 7 3.1 模态参数识别主要方法 h 7 3.2 最小二乘复频域法 h 9 3.2.1 最小二乘复频域法简介 h 9 3.2.2系统模型的确定 h 9 4 白车身模态试验 h 10 4.1 白车身参数 h 10 4.2 试验结构的支撑方式 h 10 4.3 传感器的选择及布置原则 h 12 4.4 激励系统 h 13 4.4.1 激励方式 h 13 4.4.2 振动激励源的选择和比较 h 14 4.4.3 设备传感器 h 15 4.5 试验测试系统检验 h 16 5 试验测试结果及分析 h 21 5.1 稳态图 h 21 5.2 模态频率与阻尼比 h 23 5.3 模态振型 h 24 5.4 模态试验的有效性 h 26 6 有限元分析结果与试验结果对比 h 30 结论 h 33 谢辞 h 34 参考文献 h 35  白车身模态试验方法研究 摘要：本文的目的在于研究模态分析参数识别不同方法之间的优缺点，重点是PolyMAX法和时域分析法之间的对比，以研究通过何种方法才能获得精确地实验数据。为此本文分别采用多参考最小二乘复频域（PolyMAX）法和时域分析法对结构模态参数进行识别，得到白车身各阶的模态图、模态频率和振型并采用模态置信判据法(MAC)验证试验结果，比较二者之间的优缺点，从而发现PolyMAX能提供比时域法法更多的稳定极点并且有一个清晰地图标，确保一个用户独立和简洁明了的解释，大量简化了鉴别过程。为进一步验证PolyMAX法的准确性，将PolyMAX分析结果与有限元分析相对比，发现两者具有相当高的一致性。因此，本文认为在白车身模态试验中PolyMAX法是最佳的试验模态分析方法。 关键词：白车身　模态试验　分析方法　MIMO PolyMAX Abstract：In this paper ,by comparing the advantages and disadvantages of the main modal analysis methods as frequency domain method ,time domain method ,SISO and MIMO law ,choose the MIMO method to measure the modal of Body-in-white. A 3D geometrical Model is built for testing and based on this the MIMO method (multi-input and multi-output) is applied to measure the modal of Body-in-White in “free-free” boundary conditions. And the modal parameters are estimated with the Least Square Complex Frequency (PolyMAX) method and the domain method. Every modal have been obtained by experiment and the testing result is verified by using Modal Assurance Criteria. The frequency and mode of every modal have been obtained by experiment and the testing result is verified by using Modal Assurance Criteria. Contrasting the experimental results and the finite element analysis results of the body-in-white indicate that at 60Hz or less, the result of modal testing and analysis are generally consistent. It exposed that both in the low-frequency stage e