Use of Strain Gages for Low Temperature Thermal Expansion Measurements

The use of strain gages for low temperature thermal expansion measurements is increasing, due to it's convenience, and relative accuracy. The determination of thermal expansion with strain gages is complicated by "thermal output strain", a phenomena caused by the temperature dependence of the gage. If thermal output strain is properly compensated , strain gages may be used to measure thermal expansion in much the same manner they are used to measure applied strain. An algebraic method to compensate strain gage thermal output over the temperature range 300 K to 4 K is reported here. The results of the thermal expansion tests on two structural alloys and two superconductors are also reported .