Effect of temperature on vibrating wire strain gauges

摘要

Vibrating wire strain gauges attached to buried pipe can exhibit changes in strain readings when subjected to changes in ground temperature. It is essential that the correct interpretation is placed upon the readings. An analysis is given which, it is suggested, will give true pipe strain values from the indicated strain readings. Two solutions are outlined, a graphical analysis which tends to be intuitive and a theoretical analysis which derives a solution from first principles.True strain in the pipe is influenced by thermal effects due to changes in ground temperature, and mechanical effects due to the constraint placed upon the pipe by the surrounding soil. Both analyses consider the thermal and mechanical components of true strain and the theoretical analysis enables these individual components to be determined from the indicated strain readings.