In preparation for the challenges presented by future spacecraft systems, we explore state-of-the-art testing technologies and compare the results to demonstrated, proven methods. A non-contact Polytec PSV-400 scanning laser vibrometer (SLV) is used to characterize the frequency response of a 2 meter reflector in a typical modal test configuration. Complementary measurements are made simultaneously using a conventional accelerometer-based system, and the results are compared to determine the effectiveness of the non-contact tool. The SLV has two distinct advantages that make it an attractive alternative for studying the structural dynamic response of lightweight, high-precision, aerospace structures—increased bandwidth (0.01 Hz-80kHz) and resolution at the nanometer scale. These features are available without modifying the structure, and they do not require labor-intensive preparation of the test article. Typical setup time is less than 1 hour. However, the one-dimensional (1D) SLV system is limited to measurement of the out-of-plane response of a surface one discrete point at a time, and it relies on software to render the global response. This differs fundamentally from a dedicated accelerometer system that may collect tri-axial information at hundreds of points simultaneously. Several different system configurations were tested, and the results, as well as lessons learned, will be presented.
Scanning Laser Vibrometer: Evaluation of an Alternative Modal Survey Tool
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Sarah Brennan, Reem Hejal, Mike Ryan, Stepan Simonian, Chad Stimson, David Velasco; Scanning Laser Vibrometer: Evaluation of an Alternative Modal Survey Tool. Journal of the IEST 1 October 2007; 50 (2): 14–37. doi: https://doi.org/10.17764/jiet.50.2.g8ur61027601mg72
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