A scanning laser Doppler vibrometer for modal testing
- Georgia Institute of Technology, Atlanta (USA)
Accelerometers are widely used to sense structural response in modal testing. The mass loading and local effects due to accelerometers are not always negligible. The laser Doppler velocimeter/vibrometer (LDV) is a noncontact optical sensing tool for accurately measuring point velocities. The noncontact nature of the instrument makes it particularly attractive for use on lightweight structures where measurement interaction must be minimized. Real-time scanning LDV's have recently been introduced to measure fluid flow velocity profiles rapidly. In this paper, the development of a real-time scanning LDV for structural applications is described. The instrument can be used to simultaneously measure the velocity response at a series of locations on a vibrating structure. Standard modal analysis techniques can then be applied to extract the usual modal data, e.g., natural frequencies, damping and mode shapes. The special case of beam vibration is considered in this paper though the technique can be readily extended to generic planar measurements. The measurement technique has been validated through modal testing of a simple beam structure. Comparisons between theoretical and LDV measured mode shapes and natural frequencies are presented. 20 refs.
- OSTI ID:
- 6328412
- Journal Information:
- International Journal of Analytical and Experimental Modal Analysis; (USA), Vol. 5; ISSN 0886-9367
- Country of Publication:
- United States
- Language:
- English
Similar Records
Contact Versus Non-Contact Measurement of a Helicopter Main Rotor Composite Blade
A multi-point laser Doppler vibrometer with fiber-based configuration