Strategic placement of accelerometers to measure forces by the sum of weighted accelerators
A force identification method using a sum of weighted accelerations (SWA) has recently been demonstrated. Accuracy of the SWA method depends on the number and placement of the accelerometers and the selection of the best set of weighting factors. Procedures have been proposed for determining the number of accelerometers required for a given frequency bandwidth and an experimental-analytical method has been derived to calculate the optimum set of weighting coefficients. A procedural method is described and demonstrated in this paper for determining the placement of gages using results from a free-body modal characterization. Our proposed procedure is to place accelerometers at the nodes of the highest free-body vibrational mode in the frequency bandwidth of interest. All modes below this mode are well represented in the acceleration measurements. The weighting factors can be determined by the previously reported methods or according to a theoretical method introduced in this paper. The present method satisfies the objective of ''zeroing-out'' the contribution of free-body vibration modes in the SWA method of force identification. We illustrate the theory through the analysis of a simple beam, and we then demonstrate the procedure with the laboratory testing of a softly suspended aluminum beam.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5215955
- Report Number(s):
- SAND-87-2567; ON: DE88007495
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
47 OTHER INSTRUMENTATION
ACCELERATION
MEASURING METHODS
WEIGHTING FUNCTIONS
ACCELEROMETERS
POSITIONING
ALUMINIUM
EXPERIMENTAL DATA
MECHANICAL VIBRATIONS
STRUCTURAL BEAMS
DATA
ELEMENTS
FUNCTIONS
INFORMATION
MEASURING INSTRUMENTS
METALS
NUMERICAL DATA
420200* - Engineering- Facilities
Equipment
& Techniques
440300 - Miscellaneous Instruments- (-1989)