Standard Test Methods for Performance Characteristics of Metallic Bonded Resistance Strain Gages

Importancia y uso:

4.1 Strain gages are the most widely used devices for the determination of materials, properties and for analyzing stresses in structures. However, performance characteristics of strain gages are affected by both the materials from which they are made and their geometric design. These test methods detail the minimum information that must accompany strain gages if they are to be used with acceptable accuracy of measurement.

4.2 Most performance characteristics of strain gages require mechanical testing that is destructive. Since test strain gages cannot be used again, it is necessary to treat data statistically and then apply values to the remaining population from the same lot or batch. Failure to acknowledge the resulting uncertainties can have serious repercussions. Resistance measurement is non-destructive and can be made for each strain gage.

4.3 Properly designed and manufactured strain gages, whose performance characteristics have been accurately determined and with appropriate uncertainties applied, represent powerful measurement tools. They can determine small dimensional changes in structures with excellent accuracy, far beyond that of other known devices. It is important to recognize, however, that individual strain gages cannot be calibrated. If calibration and traceability to a standard are required, strain gages should not be employed.

4.4 To be used, strain gages must be bonded to a structure. Good results depend heavily on the materials used to clean the bonding surface, to bond the strain gage, and to provide a protective coating. Skill of the installer is another major factor in success. Finally, instrumentation systems must be carefully designed to assure that they do not unduly degrade the performance of the strain gages. In many cases, it is impossible to achieve this goal. If so, allowance must be made when considering accuracy of data. Test conditions can, in some instances, be so severe that error signals from strain gage systems far exceed those from the structural deformations to be measured. Great care must be exercised in documenting magnitudes of error signals so that realistic values can be placed on associated uncertainties.

Subcomité:

E28.01

Referida por:

E2208-02R18E01, D3039_D3039M-17, D7249_D7249M-20, C1862-17, E1450-24, E1237-20, D3410_D3410M-16E01, D6416_D6416M-16R24, D4255_D4255M-20E01, D8067_D8067M-17, E0083-23, E0083-23, E0083-23, D5450_D5450M-22, E1012-19, E1012-19, E1012-19, E0009-19, D7958_D7958M-17, D5467_D5467M-97R17, D7291_D7291M-22, D5449_D5449M-22, D5448_D5448M-22, D5379_D5379M-19E01, E1012-19, D8510_D8510M-23, D6856_D6856M-23, D7248_D7248M-23, D3039_D3039M-17, D8387_D8387M-23, D7078_D7078M-20E01, E0009-19, D8337_D8337M-21, E2533-21, E0837-20, C1773-21, C1869-18R23

Volúmen:

03.01

Número ICS:

19.060 (Mechanical testing)