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Transverse Sensitivity
Because at least one of the gage grids in any rosette will in every case be subjected to a transverse strain which is equal to or greater than the strain along the grid axis, consideration should always be given to the transverse-sensitivity error when performing rosette data reduction. The magnitude of the error in any particular case depends on the transverse-sensitivity coefficient ( ) of the gage grid, and on the ratio of the principal strains ( / ). In general, when < 1%, the transverse-sensitivity error is small enough to be ignored. However, at larger values of , depending on the required measurement accuracy, correction for transverse sensitivity may be necessary. Detailed procedures, as well as correction equations for all cases and all rosette types, are given in Tech Note TN-509, Transverse Sensitivity Errors .

Thermal Effects
When strain measurements must be made in a variable thermal environment, the thermal output of the strain gage can produce rather large errors, unless the instrumentation can be zero-balanced at the testing temperature, under strain-free conditions. In addition, the gage factor of the strain gage changes slightly with temperature. Tech Note TN-504, Strain Gage Thermal Output & Gage Factor Variation with Temperature , provides a thorough treatment of errors due to thermal effects in strain gages, including specific compensation and correction techniques for minimizing these errors.

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