Optimization of excitation and measurement location in experimental modal test
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摘要: 有限元模型和试验结果的相关性分析的关键问题之一是确定最优激励点.给出了利用有限元模型和基于模态参与理论的新准则选择模态试验最佳激励点的方法,该新准则被称为模态参与变异系数准则.结合印制电路板案例,分别利用新准则和模态参与理论选择了最优激励点和次优激励点,通过对比论证了提出的新准则的准确性.此外,利用了系统等效缩减/扩展方法,用模态置信准则和共位模态置信准则来揭示不恰当的测试点带来的误差.结合印制电路板案例分析了测试点的选择对相关性分析结果的影响.案例表明,选择更好的测试点能够得到更好的相关性分析结果.Abstract: Determining the best excitation point is one of the key problems in correlation analysis. To choose the best excitation point, finite element model and a new criterion based on Mode Participation which was named coefficient of variance of mode participation criterion (CVMPC) were studied and presented. PCB case studies were presented to validate the new criterion. In the case study, the best excitation point and second best point were selected by using both CVMPC and Mode Participation method, comparison was made to show better results presented by CVMPC. The system equivalent reduction expansion process (SEREP), modal assurance criteria (MAC) and coordinate modal assurance criteria (CoMAC) were used to show the error introduced by inappropriate selection of measurement points. PCB case studies were presented to show effects of measurement points selection on correlation analysis. The case studies suggest that better results yielded by more selective picking of measurement points.
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