SCANNING LASER DOPPLER TECHNIQUES FOR VIBRATION TESTING

The feasibility of using a scanning LDV to measure the mode shape of a vibrating structure has been shown. The technique of simultaneously gathering vibration velocity information from multiple locations along the scan has been demonstrated. This makes it possible to obtain the velocity simultaneously from multiple points using a single-sensor system. A new data-processing technique extracts Cheby-shev approximations to the velocity profile. The scanning LDV provides a measuring tool that is noncontacting and adds no mass to the structure. The mode-shape data from measurements using the scanning LDV exhibit good agreement with theoretical predictions. Additional work is necessary to exploit the benefits of this development and to apply it to other important practical problems like separation of interacting modes and nonharmonic or random vibrations.