Improved Strain Gage Instrumentation Strategies for Rotorcraft Blade Measurements

Abstract:
In this presentation, a new strategy is presented to wire, calibrate, and measure strain gages for rotor blade testing that will provide more information and is robust to individual gage loss. The additional information can be used in several ways. including reducing redundancy, offering rapid identification of damage locations, and in some cases reducing risk allowing tests to continue to collect calibrated data after one or more sensors have failed. This strategy replaces the classical four-gage full Wheatstone bridge with four separately wired quarter bridges that are combined into a full bridge in the data acquisition system using a calculated channel. This strain gaging concept also provides the engineer with data from the four individual stresses, as well as the calibrated full bridge output that has been converted into engineering units.

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