基于共振法的简支梁模态实验设计OA

To solve the problem that improper data acquisition or processing methods could affect the quality of resonance method-based modal experiments,a software operating system for point-by-point dynamic plotting of mode shapes was designed based on LabVIEW.In the experiment,signals from ac-celer-ation sensors at measuring points and a reference point were first synchronously acquired.The am-plitude,frequency,and phase of the signals were estimated using a correction method based on the Hanning window spectrum.Then,the in-phase property of the signals was judged according to whether their phase difference was within a certain range.Subsequently,the mode shape diagrams at the measur-ing points were plotted by combining the amplitude ratio and the phase similarity or dis-similarity of the signals.Experimental results show that this scheme eliminates the problems of severe mode shape distortion and measurement inconsistency compared with the testing scheme in which the reference point signal is only used to judge phase similarity or difference,and the vibration amplitude at the mea-suring point serves as the mode shape value.