Strain-Gage Selection in Loads Equations Using a Genetic Algorithm
Nelson II, Sigurd A. (1994) Strain-Gage Selection in Loads Equations Using a Genetic Algorithm. Technical Report NASA CR-4597, Research Engineering, NASA Dryden Flight Research Center.
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Abstract
Traditionally, structural loads are measured using strain gages. A loads calibration test must be done before loads can be accurately measured. In one measurement method, a series of point loads is applied to the structure, and loads equations are derived via the least squares curve fitting algorithm using the strain gage responses to the applied point loads. However, many research structures are highly instrumented with strain gages, and the number and selection of gages used in a loads equation can be problematic. This paper presents an improved technique using a genetic algorithm to choose the strain gages used in the loads equations. Also presented are a comparison of the genetic algorithm performance with the current T-value technique and a variant known as the Best Step-down technique. Examples are shown using aerospace vehicle wings of high and low aspect ratio. In addition, a significant limitation in the current methods is revealed. The genetic algorithm arrived at a comparable or superior set of gages with significantly less human effort, and could be applied in instances when the current methods could not.
| EPrint Type: | NASA Contractor Report |
|---|---|
| Keywords: | Columns space, Data channel selection, Gage selection methods, Genetic algorithms, Loads equations, Structural calibration |
| Subjects: | (01 - 09) Aeronautics: (05) Aircraft Design, Testing And Performance (31 - 39) Engineering: (39) Structural Mechanics Aircraft/Project: F-111 Aircraft/Project: Space Shuttle Orbiter |
| ID Code: | 235 |
| Deposited On: | 21 July 2004 |
| Additional Information: | 20 pages. NASA Dryden Technical Monitor: Steve Thornton |
